Consumer medicine information

Naropin

Ropivacaine hydrochloride

BRAND INFORMATION

Brand name

Naropin Injection

Active ingredient

Ropivacaine hydrochloride

Schedule

S4

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Naropin.

What is in this leaflet

This leaflet answers some of the common questions people ask about NAROPIN®. It does not contain all the information that is known about NAROPIN.

It does not take the place of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor will have weighed the risks of you using NAROPIN against the benefits they expect it will have for you.

If you have any concerns about taking this medicine, ask your doctor or pharmacist.

Keep this leaflet.

You may need to read it again.

What NAROPIN is for

NAROPIN is a local anaesthetic (an-a-set-ik). It is injected into the body where it makes the nerves unable to pass messages to the brain. Depending on the amount used, NAROPIN will either totally stop pain or will cause a partial loss of feeling.

NAROPIN is used as an anaesthetic to stop the pain of surgery and/or to make childbirth less painful. NAROPIN is also used after surgery to treat post-operative pain.

Your doctor will have explained why you are being treated with NAROPIN and told you what dose you will be given.

Follow all directions given to you by your doctor carefully.

They may differ from the information contained in this leaflet.

Your doctor may prescribe this medicine for another use. Ask your doctor if you want more information.

NAROPIN is not addictive.

Before you are given NAROPIN

When you must not use it

NAROPIN must not be used if:

  1. you have any allergies to
  • any ingredient listed at the end of this leaflet
  • any other local anaesthetics
  1. you have problems controlling your low blood pressure
  2. you have inflammation and/or an infection at the site of injection

Before you start to use it

  • You must tell your doctor if:
  1. you have any allergies to other substances
  2. you have any of these medical conditions
  • problems with your blood pressure or circulation
  • blood poisoning
  • problems with the clotting of your blood
  • acidosis, or too much acid in the blood
  • nerve problems
  • liver, kidney or heart problems
  • disease of the brain or spine, including meningitis, polio, cancer or infections.
  • muscle disease or weakness (e.g. myasthenia gravis)
  1. you are pregnant, are breast feeding or intend to breast-feed.

Your doctor will discuss the possible risks and benefits of using NAROPIN during pregnancy and breast-feeding.

It may not be safe for you to be given NAROPIN if you have any of these conditions.

NAROPIN will only be used if the solution is clear, the package is undamaged and the use by (expiry) date marked on the pack has not been passed.

Taking other medicines

You must tell your doctor if you are taking any other medicines, including

  • medicines that control your heart beat
  • medicines used to thin the blood, including aspirin
  • low molecular weight heparin or other medicines used to prevent blood clots
  • fluvoxamine, a medicine used to treat depression.
  • enoxacin, a medicine used to treat bacterial infections.
  • ketoconazole, a medicine used to treat fungal infections
  • cimetidine, a medicine used to treat stomach ulcers or heartburn
  • medicines for depression
  • medicines that you buy at the pharmacy, supermarket or health food shop.

These medicines may affect the way NAROPIN works.

Your doctor or pharmacist can tell you what to do if you are taking any of these medicines.

If you have not told your doctor about any of these things, tell them before you are given any NAROPIN.

Using NAROPIN

How it will be given

NAROPIN will be injected by your doctor into the skin, near a single nerve, or into an area which contains a large number of nerves. Naropin may also be directed into a surgical incision after surgery by a tube.

This will result in an area of numbness at or near the site of administration, or in an area that may seem unrelated to the site of administration. The latter will be the case if you are given an EPIDURAL injection (an injection around the spinal cord).

NAROPIN should not be injected directly into the blood.

The dosage you will be given will depend on your body size, age and the type of pain relief required. Your doctor will have had a lot of experience using NAROPIN or other local anaesthetics and will choose the best dose for you. They will be willing to discuss this decision with you.

Overdose

The doctor giving you NAROPIN will be experienced in the use of local anaesthetics, so it unlikely that you will be given too much.

However, if you are particularly sensitive to NAROPIN, or the dose is accidentally injected directly into your blood, you may develop problems with your sight, hearing, and get a numb feeling in or around the mouth, feel dizzy or stiff, or have twitchy muscles.

In rare cases, these effects may be followed by drowsiness and fits. In extreme cases you may have problems with your breathing or your heart and you may become unconscious.

While you are being given it

Things to be careful of

Be careful driving or operating machinery after you have been given NAROPIN.

You may be drowsy and your reflexes may be slow.

Do not drink alcohol while you are being given NAROPIN.

If you drink alcohol while you are being given NAROPIN your blood pressure may drop making you feel dizzy and faint.

Please talk to your doctor or pharmacist about these possibilities if you think they may bother you.

Side effects

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking NAROPIN.

NAROPIN will help relieve pain in most people, but it may have unwanted side-effects. All medicines can have side effects. Sometimes they are serious, most of the time they are not.

You may need medical treatment if you get some of the side effects.

Ask your doctor or pharmacist to answer any questions you may have.

Tell your doctor if you notice any of the following and they worry you:

  • nausea (feeling sick)
  • vomiting
  • headache
  • dizziness
  • irregular or slow heart beat
  • fever
  • a tingling feeling ("pins and needles")
  • shivering
  • difficulty passing urine

These are all mild side effects of NAROPIN.

Tell your doctor or a nurse immediately if you notice any of the following:

  • stiff or twitching muscles
  • painful joints
  • difficulty breathing
  • extreme dizziness
  • slow heart beat
  • pain in the chest
  • fits

On rare occasions you may lose consciousness.

These are all serious side effects. You may need urgent medical attention

Serious side effects are rare.

Tell your doctor if you notice anything else that is making you feel unwell.

Some people may get other side effects while taking NAROPIN.

After using it

Storage

NAROPIN will be stored by your doctor or pharmacist under the recommended storage conditions.

It should be kept in a cool dry place where the temperature stays below 30°C.

Disposal

Any NAROPIN which is not used, and which is left in the container, will be disposed of in a safe manner by your doctor, nurse or pharmacist.

Product description

NAROPIN is a clear colourless solution for injection or infusion.

The active ingredient is ropivacaine hydrochloride, plus

  • sodium chloride
  • hydrochloric acid or
  • sodium hydroxide for pH adjustment
  • water for injections.

Naropin®0.2% (2.0 mg/mL), 0.75% (7.5 mg/mL) and 1% (10.0 mg/mL) are available in 10 mL and 20 mL polypropylene ampoules (Polyamp®DuoFit®)

Naropin®0.2% (2.0 mg/mL) is also available in 100mL and 200mL polypropylene infusion bags (Polybag®)

BRAND INFORMATION

Brand name

Naropin Injection

Active ingredient

Ropivacaine hydrochloride

Schedule

S4

 

Name of the medicine

Ropivacaine hydrochloride.

Excipients.

Water for Injections BP, sodium hydroxide or hydrochloric acid to adjust pH to between 4.0 and 6.0; preservative free.

Description

Chemical name: (S)-(-)-propyl-piperidine-2-carboxylic acid (2,6-dimethyl-phenyl)-amide hydrochloride monohydrate. Molecular formula: C17H26N2O.HCl.H2O. MW: 328.89. CAS: 84057-95-4 (free base). Ropivacaine hydrochloride is a white crystalline powder and has a water solubility of about 50 mg/mL. Ropivacaine hydrochloride was developed as the pure S-(-)-isomer and has an enantiomeric purity of > 99%. It has a pKa of 8.1 (at 25°C). The pH of a saturated solution of ropivacaine hydrochloride is 4.5 and that of a 1% (w/v) aqueous solution is 5.0.
Naropin solution for injection is a sterile, isotonic, isobaric, aqueous solution of ropivacaine HCl in Water for Injections BP. The pH of the solution is adjusted with sodium hydroxide or hydrochloric acid to remain between 4.0-6.0 during the approved shelf-life. The nominal osmolality of Naropin 0.2% (2 mg/mL) is 288 mOsmol/kg. The solution is preservative free.
The presentations of Naropin injection solutions are intended for single use only. Any solution remaining from an opened container should be discarded.

Pharmacology

Ropivacaine has both anaesthetic and analgesic effects. At higher doses it produces surgical anaesthesia with motor block, while at lower doses it produces a sensory block (including analgesia) with little motor block.
The duration and intensity of ropivacaine sensory block is not improved by the addition of adrenaline.
Ropivacaine, like other local anaesthetics, causes reversible blockade of impulse propagation along nerve fibres by preventing the inward movement of sodium ions through the cell membrane of the nerve fibres. It is the first long acting amide local anaesthetic developed as a pure enantiomer. There is no evidence of in vivo racemisation of ropivacaine.

Pharmacodynamics and tolerability.

The local anaesthetic effect of ropivacaine and its R-(+) enantiomer was evaluated for sciatic block, spinal anaesthesia and infiltration anaesthesia over a wide concentration range (0.25 to 1.0%) in a number of animal species and a concentration (dose) response relationship was ascertained. These studies supported the selection of the enantiomerically pure drug ropivacaine, and are consistent with the observations with other local anaesthetics that the S-(-) form is less toxic and/or has a longer duration of action than the R-(+) form.
In vitro testing of ropivacaine conduction anaesthesia indicates that ropivacaine is comparable to or slightly more potent than bupivacaine in blocking sensory fibres, and is less active in blocking motor fibres.
The anaesthetic effects of ropivacaine were evaluated in peripheral (sciatic nerve and brachial plexus) and central (spinal and epidural) neural blocks, as well as in infiltration and topical anaesthesia, in a large number of studies using multiple animal species including mouse, rat, guinea pig, dog, sheep and Rhesus monkey.
The peripheral neural block studies indicate that a concentration of ropivacaine of 0.5 to 1.0% consistently produces effective sensory and motor block. Neither increasing the concentration above 0.75% nor adding adrenaline significantly improved the duration of motor block or anaesthesia with ropivacaine.
For central neural blockade, in all species studied, it appeared that onset times of epidural anaesthesia with ropivacaine and bupivacaine were similar. The concentration required to consistently produce complete motor blockade with epidural anaesthesia appeared to be 0.75 to 1.0% for ropivacaine. The duration of sensory block appeared to be comparable for equal concentrations of ropivacaine and bupivacaine.
Tests of infiltration anaesthesia in guinea pigs showed that ropivacaine was markedly superior to bupivacaine in producing sustained cutaneous anaesthesia at all concentrations. The duration of anaesthesia produced with the least effective ropivacaine concentration (0.25%) far exceeded that produced by the highest bupivacaine concentration (0.75%).
For analgesia, the potency of ropivacaine is similar to that of bupivacaine. For motor block, the potency was found to be around 80% of bupivacaine.
Ropivacaine and bupivacaine are equipotent in producing seizures in rats and dogs. In both pregnant and nonpregnant sheep, ropivacaine was less toxic than bupivacaine.
Comparisons with the short acting local anaesthetic lignocaine show that the doses needed to produce seizures are two (in sheep) to four (in rats and dogs) times the dose of ropivacaine. In studies in sheep, ropivacaine appears to have less central nervous system and cardiovascular toxicity than bupivacaine, and pregnancy does not appear to enhance sensitivity in either the central nervous system or in cardiac membranes as has been reported in some studies with bupivacaine.
In vitro heart studies indicate that the effects of ropivacaine on conduction and contractility are less compared to bupivacaine. The risk of ventricular tachycardia is less with ropivacaine than bupivacaine. Atrial and ventricular pacing were more successful during exposure to high concentrations of ropivacaine compared to bupivacaine. The in vitro electrophysiological studies are consistent with the findings in the in vitro heart preparation.
Cardiovascular effects measured in vivo in animal studies showed that ropivacaine is consistently well tolerated and that ropivacaine is less likely than bupivacaine to produce ventricular arrhythmias. Resuscitative measures were highly successful in dogs given large overdoses of ropivacaine (9.8 mg/kg intravenously). In most preclinical studies of the cardiovascular effects, comparisons were also made with lignocaine. In general, all results were consistent with the observation that a given dose of lignocaine was less toxic than an equivalent dose of ropivacaine or bupivacaine.
In man, ropivacaine is less toxic regarding the CNS and cardiovascular systems than bupivacaine. In two tolerability studies in volunteers given IV infusions, CNS symptoms appeared at higher doses and higher free plasma concentrations of ropivacaine compared to bupivacaine. The ropivacaine dose response and concentration response curves for CNS symptoms, e.g. muscular twitching and dysarthria, were consistently shifted to the right compared with those of bupivacaine. A threshold for CNS toxicity was apparent at a free plasma concentration of ropivacaine 0.34 mg/L and bupivacaine 0.13 mg/L. Ropivacaine caused a smaller increase in the QRS width and less pronounced reduction in diastolic and systolic function of the left ventricle as compared to bupivacaine.
2,6-pipecoloxylidide (PPX) is an active metabolite. The threshold for systemic CNS toxic unbound plasma concentrations of PPX in rats is about twelve times higher than that of unbound ropivacaine.
Factors which may increase the relative systemic toxicity of local anaesthetics are acidosis and severe hepatic dysfunction.
Ropivacaine, like bupivacaine and other local anaesthetics, produces vasoconstriction at lower concentrations and vasodilation at higher concentrations. These findings appear to be consistent both in vivo and in vitro.

Pharmacodynamic interactions.

In preclinical studies in rats, ropivacaine interacts with agents used in conjunction with regional anaesthesia, such as benzodiazepines, thiopental, enflurane, pancuronium, suxamethonium and fentanyl, in a manner similar to that produced by the commonly used local anaesthetics bupivacaine and lignocaine. In rats, pretreatment with ropivacaine potentiated the sedative effect of morphine compared to placebo.
Pharmacodynamic drug interactions of local anaesthetics probably depend more on the physiological effects of the block, such as hypotension and bradycardia, than on circulating blood levels of the local anaesthetic.

Pharmacokinetics.

The plasma concentration of ropivacaine depends upon the dose, the route of administration and the vascularity of the injection site. Ropivacaine has linear pharmacokinetics and the maximum plasma concentration is proportional to the dose.
Ropivacaine shows complete and biphasic absorption from the epidural space with half-lives of the two phases in the order of 14 minutes and four hours. The slow absorption is the rate limiting factor in the elimination of ropivacaine, which explains why the apparent elimination half-life is longer after epidural than after intravenous administration. Ropivacaine shows a biphasic absorption from the caudal epidural space also in children.
The pharmacokinetic profile of ropivacaine in adults following experimental intravenous administration is summarised as follows. Plasma clearance: 440 mL/minute; unbound plasma clearance: 8 L/minute; renal clearance: 1 mL/minute; volume of distribution at steady state: 47 L; unbound volume of distribution at steady state: 819 L; terminal half-life: 1.8 hours; unbound fraction: 0.06; hepatic extraction ratio: 0.4; major metabolite: 3-hydroxyropivacaine.
Ropivacaine is mainly bound to α1-acid glycoprotein in plasma with an unbound pharmacologically active fraction of about 6%. An increase in total plasma concentrations during continuous postoperative epidural infusion and interscalene infusion has been observed. This increase is related to a postoperative increase of α1-acid glycoprotein. Variations in unbound concentration of ropivacaine have been much less than in total plasma concentration.
Ropivacaine is extensively metabolised, predominantly by aromatic hydroxylation. In total, 86% of the dose is excreted in the urine after intravenous administration, of which only about 1% is unchanged drug. Approximately 9% is excreted in faeces.
Both the dealkylation (N-depropylated or PPX) and the hydroxylation pathways in the metabolism of ropivacaine are detoxification reactions. PPX is considered to have approximately one-twelfth of the pharmacological activity of ropivacaine. The hydroxylated metabolites of ropivacaine have some local anaesthetic activity (ropivacaine > 3-hydroxyropivacaine > 4-hydroxyropivacaine). The hydroxylated metabolites are rapidly conjugated in human plasma and are very unlikely to have any pharmacological or toxicological activities.
The major metabolite is 3-hydroxyropivacaine. This metabolite accounts for about 37% of urinary excretion, mainly as a glucuronide conjugate. The only metabolite which reaches detectable concentrations in plasma is 3-hydroxyropivacaine (conjugated and unconjugated). Urinary excretion of 4-hydroxyropivacaine, the N-dealkylated metabolite and the 4-hydroxydealkylated metabolite accounts for 1 to 3% of a given dose.
The NADPH-dependent metabolism of ropivacaine to 3-hydroxyropivacaine is catalysed by CYP1A2. The formation of minor metabolites in vivo is catalysed by CYP3A4. The apparent Km (affinity constant) for 3-hydroxyropivacaine is 16 micromol and about 400 micromol for the other metabolites. Of the two members in the CYP1A family, CYP1A1 is expressed only after exposure to inducers, while CYP1A2 accounts for about 10% of total P450 in the liver. (See Interactions with other medicines, Metabolic interactions.)
A similar pattern of metabolites has been found in children above 1 year.
Impaired renal function has little or no influence on ropivacaine pharmacokinetics. The renal clearance of PPX is significantly correlated with creatinine clearance. A lack of correlation between total exposure, expressed as AUC, with creatinine clearance indicates that the total clearance of PPX includes a nonrenal elimination in addition to renal excretion. Some patients with impaired renal function may show an increased exposure to PPX resulting from a low nonrenal clearance. The potential for toxicity in these patients is dependent on the total dose, dose route and duration of exposure to ropivacaine.

Paediatrics.

The pharmacokinetics of ropivacaine were characterised in a pooled population PK analysis on data in 192 children between 0 and 12 years from six studies (three on caudals, two on epidural infusions and one on ilioinguinal block). Unbound ropivacaine and PPX clearance and ropivacaine unbound volume of distribution initially, depend on both bodyweight and age up to 3 years, after which they depend largely on bodyweight. The maturation of unbound ropivacaine clearance appears to be complete by the age of 3 years, that of PPX by the age of 1 year and unbound ropivacaine volume of distribution by the age of 2 years. The PPX unbound volume of distribution only depends on bodyweight.
Unbound ropivacaine clearance increases from 2.4 and 3.6 L/hour/kg in the newborn and the 1 month neonate to about 8 to 16 L/hour/kg for ages above 6 months, values within the range of those in adults. Total ropivacaine clearance values/kg bodyweight increase from about 0.10 and 0.15 L/hour/kg in the newborn and the 1 month neonate to about 0.3 to 0.6 L/hour/kg beyond the age of 6 months. Unbound ropivacaine volume of distribution/kg bodyweight increases from 22 and 26 L/kg in the newborn and the 1 month neonate to 42 to 66 L/kg above 6 months. Total ropivacaine volume of distribution/kg bodyweight increases from 0.9 and 1.0 L/kg for the newborn and the 1 month neonate to 1.7 to 2.6 L/kg beyond the age of 6 months. The terminal half-life of ropivacaine is longer, six to five hours in the newborn and the 1 month neonate compared to about three hours in older children. The terminal half-life of PPX is also longer, from 43 and 26 hours in the newborn and the 1 month old neonate to about 15 hours in older children.
At 6 months, the breakpoint for change in the recommended dose rate for continuous epidural infusion, unbound ropivacaine clearance has reached 34% and unbound PPX 71% of its mature value. The systemic exposure is higher in neonates and also somewhat higher in infants between 1 and 6 months compared to older children, which is related to the immaturity of their liver function. However, this is partly compensated for by the recommended 50% lower dose rate for continuous infusion in infants below 6 months.
Simulations on the sum of unbound plasma concentrations of ropivacaine and PPX, based on the PK parameters and their variance in the population analysis, indicate that for a single caudal block the recommended dose must be increased by a factor of 2.7 in the youngest group and a factor of 7.4 in the 1 to 10 year group in order for the upper prediction 90% confidence interval limit to touch the threshold for adult systemic toxicity. Corresponding factors for the continuous epidural infusion are 1.8 and 3.8, respectively.
When comparing descriptive data in a trial of caudal/ epidural infusions in ten full term neonates aged 0 to 30 days, to that in 18 older patients aged 31 to 180 days, total and unbound ropivacaine was higher and showed higher interindividual variability, unbound apparent clearance lower and ropivacaine binding to plasma proteins (α1-acid glycoprotein) was lower. There was a greater relative excretion of ropivacaine in urine. Plasma concentrations of total and unbound PPX were similar but PPX had a longer half-life. The sum of unbound concentrations of ropivacaine and one twelfth of PPX was higher in neonates 0 to 7 days. While the highest level reached was 0.24 mg/L, this may have been still rising when observations ceased at 72 hours (only four observations). The systemic CNS toxicity threshold in adults is 0.34 mg/L in a mature nervous system (see Pharmacodynamics and tolerability). It is not known how immaturity of the CNS affects toxic thresholds.
Fetuses exposed to ropivacaine during labour or caesarean section can be regarded, after they have been born, as neonates with a peak plasma concentration at the time of delivery. The maximum unbound plasma ropivacaine concentrations in the newborn as reflected in the umbilical vein at delivery, 0.03 to 0.11 mg/L, are in the same range as those seen after single caudal block in neonates and support the documentation of ropivacaine in neonates. Table 1 shows neonatal exposure based on umbilical venous plasma concentrations at delivery after epidural block for caesarean section with ropivacaine 115 to 150 mg or continuous lumbar epidural infusion with 25 mg/hour in labour.

Pharmacokinetics during pregnancy at term.

In pregnancy at term, ropivacaine clearance is somewhat lower and its unbound clearance about half of that seen after epidural administration to nonpregnant patients. Accordingly, total Cmax and unbound Cmax are higher in pregnancy. The unbound plasma concentrations in the umbilical vein at delivery were similar to those in the mother and showed a fairly rapid equilibrium. There was no obvious correlation between neonatal neurologic and adaptive capacity scores and unbound or total plasma concentrations in the newborns.

Epidural injection.

Two parallel groups of ten patients each, scheduled for epidural analgesia to relieve pain during labour, received ropivacaine or bupivacaine as a 50 mg bolus followed on request by a 25 mg top-up dose.
The unbound concentration of ropivacaine was higher than that of bupivacaine at 20 minutes, 0.04 (0.013) mg/L and 0.02 (0.008) mg/L as well as at four hours after the initial dose, 0.03 (0.006) mg/L and 0.02 (0.013) mg/L. The mean unbound fraction of ropivacaine was higher, 0.07, than that of bupivacaine, 0.04.

Epidural infusion.

Patients scheduled for epidural analgesia as pain relief during labour received a continuous lumbar epidural infusion of ropivacaine 12.5 mg/hour or 25 mg/hour, or bupivacaine 25 mg/hour, after an initial dose of ropivacaine 12.5 mg or 25 mg, or bupivacaine 25 mg. Treatment with ropivacaine 12.5 mg/hour was terminated after six patients had been withdrawn due to insufficient analgesia. The results in the two groups of ten patients, each given ropivacaine or bupivacaine 25 mg/hour (2.5 mg/mL) are described below. The rate of infusion (dose) was not changed during the course of the study.
The median duration of the infusion was 6.6 hours with ropivacaine and 7.7 hours with bupivacaine, corresponding to total mean doses of 179 and 227 mg.
The maternal unbound fraction was higher after ropivacaine than after bupivacaine. The unbound plasma clearance of ropivacaine was 3.35 (1.36) L/minute, about half that of bupivacaine, 6.40 (2.47) L/minute. The mean (SD) umbilical venous unbound fraction was 0.17 (0.09) with ropivacaine and 0.12 (0.05) with bupivacaine. The unbound UV/MV ratios did not seem to increase with the duration of the infusion, indicating rapid equilibration.
Umbilical arterial (UA) and umbilical venous (UV) unbound concentrations after continuous lumbar epidural infusion of ropivacaine and bupivacaine 25 mg/hour in labour are presented in Table 2.

Clinical Trials

Adults.

Two open label, randomised uncontrolled clinical studies were performed to document the efficacy and safety of Naropin 2 mg/mL in continuous peripheral nerve block for postoperative management up to 48 hours. In total 163 patients were studied, 136 received femoral block and 27 interscalene block. Continuous peripheral nerve blocks with Naropin provided effective postoperative pain relief in both studies. Patient satisfaction was reported to be high.
Four open label, randomised studies were performed to investigate the efficacy and safety of Naropin 0.5% (5 mg/mL) and other strengths for intrathecal administration in surgical anaesthesia. A total 224 patients were studied, of which 217 patients were valid for safety and 212 for efficacy. In two studies, patients underwent minor orthopaedic, gynaecological or urological surgery suited for spinal anaesthesia. In the other two studies, patients underwent a unilateral hip replacement. Naropin 15 to 20 mg administered intrathecally was effective and the anaesthetic quality was rated high by surgeons, anaesthetists and patients. The incidence and severity of adverse events reported were not related to dose.

Paediatrics.

A total of five studies, involving 246 patients aged 0 to 12 years, were performed to evaluate the use of Naropin 2 mg/mL (0.2%) for caudal block (three studies) and continuous epidural infusion (two studies). In the studies on caudal block, the given volumes of the ropivacaine solutions were 1 mL/kg. In one of these studies in paediatric patients between 4 and 12 years of age, three different dosages of Naropin (1, 2 and 3 mg/kg, 0.1, 0.2 and 0.3%) were compared. Adequate efficacy with minimal motorblock was found for the 2 mg/kg dose. In another study on caudal block in neonates and infants between 0 and 12 months of age, the analgesic efficacy was similar to the efficacy in paediatric patients above 1 year of age, given the same dose/kg (2 mg/kg), when assessed as the proportion of patients with postoperative pain, time to first pain and time to treatment with supplementary analgesics.
In two studies in patients 1 day to 12 years old an epidural bolus was followed by a continuous infusion for up to 72 hours. The epidural bolus volume ranged between 0.5 and 1 mL/kg of ropivacaine 2 mg/mL (0.2%), with lower volumes given for thoracic than for lumbar injections. The infusion rate was ropivacaine 2 mg/mL (0.2%) 0.2 mg/kg/hour in neonates and infants below 6 months of age and 0.4 mg/kg/hour in patients above 6 months of age. More than 80% of the patients had no/ mild pain, or were asleep, at any time point. There was no difference in pain score between the 0 to 6 months group (ropivacaine 0.2 mg/kg/hour infusion) and the 6 to 12 months group (ropivacaine 0.4 mg/kg/hour infusion). The median time to supplementary analgesia was 3.3 hours in patients older than 1 year, whereas in younger patients less than 40% had been given supplementary analgesia after 72 hours. Motor block was observed in 32% of the patients above 1 year of age but in none of the infants below 1 year of age. Ropivacaine was well tolerated in all paediatric age groups.

Indications

Surgical anaesthesia.

Adults and children over 12 years of age.

Epidural block for surgery including caesarean section; intrathecal anaesthesia; field block (minor nerve block and infiltration); major nerve block.

Analgesia.

Adults and children over 12 years of age.

Continuous epidural infusion or intermittent bolus epidural administration for analgesia in postoperative or labour pain; field block (minor nerve block and infiltration); continuous peripheral nerve block infusion or intermittent injections for postoperative pain management; continuous wound infusion for postoperative pain management (adults only).

Children aged 0 to 12 years.

Caudal epidural block in neonates (> 37 weeks gestation and over 2,500 g weight), infants and children up to and including 12 years; continuous epidural infusion in infants (> 30 days and over 2,500 g weight) and children up to and including 12 years; peripheral nerve block in children aged 1 up to and including 12 years.
For perioperative and postoperative pain management.
There are no safety or efficacy data to support the use of Naropin for analgesia for longer than 72 hours. (Data for peripheral nerve block administered as a continuous peripheral infusion or intermittent injections and for continuous wound infusion support the use for up to 48 hours only.)

Contraindications

Allergy or hypersensitivity to amide type local anaesthetics. Detection of suspected hypersensitivity by skin testing is of limited value.
Intravenous administration.
Local anaesthetics are contraindicated for epidural and spinal anaesthesia in patients with uncorrected hypotension.
Local anaesthetic techniques must not be used when there is inflammation and/or sepsis in the region of the proposed injection and/or in the presence of septicaemia.
Intravenous regional anaesthesia (Bier's block), as unintentional passage of local anaesthetic into the systemic circulation, despite the use of a tourniquet, may cause systemic toxic reactions.
The use of Naropin is not recommended for obstetric paracervical block.
General contraindications related to epidural anaesthesia, regardless of the local anaesthetic used, should be taken into account.

Precautions

When any local anaesthetic agent is used, resuscitative equipment and drugs, including oxygen, should be immediately available in order to manage possible adverse reactions involving the cardiovascular, respiratory or central nervous systems. Because of the possibility of hypotension and bradycardia following major blocks, an intravenous cannula should be inserted before the local anaesthetic is injected.
Injection should always be made slowly with frequent aspirations to avoid inadvertent intravascular injection which can produce toxic effects.
Although intra-articular continuous infusions of local anaesthetics following arthroscopic and other surgical procedures is an unapproved use, there have been postmarketing reports of chondrolysis in patients receiving such infusions. The majority of reported cases of chondrolysis have involved the shoulder joint; cases of glenohumeral chondrolysis have been described in paediatric and adult patients following intra-articular continuous infusions of local anaesthetics with and without adrenaline for periods of 48 to 72 hours. There is insufficient information to determine whether shorter infusion periods are not associated with these findings. The time of onset of symptoms, such as joint pain, stiffness and loss of motion can be variable, but may begin as early as the second month after surgery. Currently, there is no effective treatment for chondrolysis; patients who experienced chondrolysis have required additional diagnostic and therapeutic procedures and some required arthroplasty or shoulder replacement. Therefore, naropin should not be used for postoperative intra-articular continuous infusion.

Low molecular weight heparins and heparinoids (spinal/ epidural haematomas).

When neuraxial anaesthesia (epidural/ spinal anaesthesia) is employed, patients anticoagulated or scheduled to be anticoagulated with low molecular weight heparins or heparinoids are at risk of developing an epidural or spinal haematoma which can result in long-term or permanent paralysis. The risk of these events is increased by the use of indwelling epidural catheters, traumatic or repeated epidural/ spinal puncture, and the concomitant use of drugs affecting haemostasis such as NSAIDs, platelet inhibitors or other anticoagulants. Patients should be frequently monitored for signs and symptoms of neurological impairment.
The safety and efficacy of Naropin depend on proper dosage, correct technique and adequate precautions. Standard textbooks should be consulted regarding specific techniques and precautions for various regional anaesthetic procedures.
The lowest dosage that results in efficacious anaesthesia should be used (see Dosage and Administration).
Elderly, young or debilitated patients, including those with partial or complete heart conduction block, advanced liver disease or severe renal dysfunction, should be given reduced doses commensurate with their age and physical condition.
Children aged between 0 and 12 years should be given doses commensurate with their weight and clinical status.
Ropivacaine is eliminated primarily by hepatic metabolism and changes in hepatic function may have significant consequences. Ropivacaine has an intermediate to low clearance which depends on its unbound fraction and intrinsic metabolic clearance. Naropin should therefore be used with caution in patients with severe hepatic disease.
Normally there is no need to modify the dose in patients with impaired renal function when used for single dose or short-term treatment. Acidosis and reduced plasma protein concentration, frequently seen in patients with chronic renal dysfunction, may increase the risk of systemic toxicity (see Dosage and Administration).
The possibility of hypotension and bradycardia following epidural and intrathecal blockade should be anticipated and precautions taken, including the prior establishment of an intravenous line and the availability of vasopressor drugs, vagolytic drugs and oxygen.
Certain local anaesthetic procedures, such as injection in the head and neck region, including retrobulbar, dental and stellate ganglion blocks, may be associated with a higher frequency of serious adverse reactions, regardless of the local anaesthetic used. The side effects may be similar to the systemic toxicity seen with unintentional intravascular injections of larger doses.
Naropin should be used with caution in patients with known drug sensitivities.
Careful and constant monitoring of cardiovascular and respiratory vital signs and the patient's state of consciousness should be accomplished after each local anaesthetic injection. It should be kept in mind that at such times restlessness, anxiety, tinnitus, dizziness, blurred vision, tremors, depression or drowsiness may be early warning signs of CNS toxicity.
Local anaesthetics should be given with great caution (if at all) to patients with pre-existing abnormal neurological pathology, e.g. myasthenia gravis. Use with extreme caution in epidural, caudal and spinal anaesthesia when there are serious diseases of the CNS or of the spinal cord, e.g. meningitis, spinal fluid block, cranial or spinal haemorrhage, tumours, poliomyelitis, syphilis, tuberculosis or metastatic lesions of the spinal cord.
Major peripheral nerve blocks may involve the administration of a large volume of local anaesthetic in highly vascularised areas, often close to large vessels where there is an increased risk of intravascular injection and/or rapid systemic absorption. This can lead to high plasma concentrations.
If Naropin is administered simultaneously by two or more different routes, the total dose and hence the risk of systemic toxicity should be considered.
Patients treated with class III antiarrhythmic drugs (e.g. amiodarone) should be under close surveillance. ECG monitoring should also be considered, since cardiac effects may be additive.
There have been reports of cardiac arrest during the use of Naropin for epidural anaesthesia or peripheral nerve blockade, especially after unintentional accidental intravascular administration in elderly patients and in patients with concomitant heart disease. In some instances, resuscitation has been difficult. Should cardiac arrest occur, prolonged resuscitative efforts may be required to improve the possibility of a successful outcome.
Neonates need special attention due to immaturity of some organs and functions. This is especially important during continuous epidural infusion. If epidural infusions are to be used in neonates, ropivacaine doses must be individually titrated by a specialist in paediatric anaesthesia. Regular monitoring for systemic toxicity (e.g. by signs of CNS toxicity, ECG, SpO2) is always required for neonates. Monitoring should be continued after completion of infusion due to decreased rates of elimination of ropivacaine in neonates. Dose recommendations have not been established in premature neonates but organ immaturity would be expected to result in even slower elimination.
Naropin is possibly porphyrinogenic and should only be prescribed to patients with acute porphyria when no safer alternative is available. Appropriate precautions should be taken in the case of vulnerable patients.

Genotoxicity.

Ropivacaine hydrochloride was negative in the Ames salmonella/ mammalian microsome mutagenicity test, human lymphocyte chromosome aberration test, mouse micronucleus test, E. coli differential DNA repair test, E. coli host mediated DNA repair test in mice, and the somatic mutation and recombination test in Drosophila melanogaster (fruit fly) and weakly mutagenic in the mouse lymphoma test. The clinical use of ropivacaine is unlikely to pose any risk of genotoxicity.

Carcinogenicity.

Long term animal assays of carcinogenic potential have not been performed.

Effects on fertility.

No adverse effects on fertility and reproductive performance were seen in rats over two generations following daily subcutaneous administration of ropivacaine from prior to mating through weaning, with estimated systemic exposure (plasma AUC) twice the clinical exposure following a 200 mg epidural dose. Increased pup loss in the first three days postpartum was attributed to reduced maternal care.

Effects on ability to drive and use machines.

Depending on the dose, local anaesthetics may have a mild effect on mental function and coordination, even in the absence of overt CNS toxicity, and may temporarily impair locomotion and alertness. Patients should be warned of this possibility and advised not to drive a motor vehicle or operate machinery if affected.

Use in pregnancy.

(Category B1)
There was no evidence of teratogenicity following daily subcutaneous administration of ropivacaine to rats and rabbits during the period of organogenesis, with estimated systemic exposure (plasma AUC) twice the clinical exposure following a 200 mg epidural dose. In rats treated similarly with ropivacaine daily from late gestation to weaning, there were no treatment related effects on late fetal development, parturition, lactation, neonatal viability, or offspring growth. In rats treated from late gestation to weaning, maternal toxicity was elicited at a lower dose and lower unbound plasma concentration with bupivacaine than with ropivacaine.
There are no clinical studies in preterm pregnant women on the effects of Naropin on the developing fetus. Naropin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
The epidural use of Naropin in obstetrics is well documented and adverse effects have been reported. (See Adverse Effects, Fetal, neonatal and infant adverse events.)
Intrathecal administration has not been documented for caesarean section.

Use in lactation.

Subcutaneous administration of ropivacaine to rats from late gestation to weaning, with estimated systemic exposure (plasma AUC) twice the clinical exposure following a 200 mg epidural dose, did not affect late fetal development, parturition, lactation, neonatal viability or offspring growth. Ropivacaine and/or its metabolites are excreted into milk in rats, but excretion into human milk has not been investigated.

Interactions

Local anaesthetics and antiarrhythmic drugs.

Naropin should be used with caution in patients receiving other local anaesthetics or agents structurally related to amide type local anaesthetics, since the toxic effects are additive. Specific interaction studies with Naropin and class III antiarrhythmic drugs (e.g. amiodarone) have not been performed, but caution is advised (see Precautions).

Adrenaline.

The duration and intensity of ropivacaine sensory block is not improved by the addition of adrenaline.

Alkaline solutions.

The solubility of ropivacaine is limited at pH values above 6. This must be taken into consideration if adding an alkaline solution since precipitation might occur at higher pH values.

Cytochrome P450 interactions.

(See Pharmacokinetics.) Ropivacaine is metabolised by the enzymes CYP1A2 and CYP3A4. Interactions with inducers of these enzymes are not expected to be clinically relevant, however, there is a potential for metabolic interaction when Naropin is used in combination with a potent enzyme inhibitor.

CYP1A2 inhibitors.

Fluvoxamine.

Oral fluvoxamine treatment caused a 70% decrease in ropivacaine clearance and a threefold higher AUC in healthy volunteers. Single administrations of Naropin should be used with care in patients who are concomitantly receiving a potent CYP1A2 inhibitor. Repeated administration or long-term infusion should be avoided in such patients.
A theoretical possibility of metabolic drug interactions with potent inhibitors of CYP1A2, such as enoxacin, may exist.

CYP3A4 inhibitors.

Ketoconazole.

Coadministration with ketoconazole, a potent inhibitor of CYP3A4, has been shown to cause a marginal (15%) decrease in ropivacaine clearance in healthy volunteers.

Theoretical interactions.

Cimetidine, an inhibitor of CYP2E1, did not inhibit the formation of 3-hydroxyropivacaine but inhibited some formation of minor metabolites in vitro.

Metabolic interactions.

With the low to intermediate hepatic extraction ratio of ropivacaine (mean 0.4), a fall in the liver blood flow is not expected to have a significant influence on ropivacaine clearance (see Precautions, Impaired hepatic function).

Clinical relevance of interactions.

In the clinical experience with Naropin, patients usually received Naropin in combination with several other therapies. The safety evaluation of Naropin is, therefore, based upon its use in combination with various concomitant treatments. The review of safety data in these studies shows that Naropin has a safety profile comparable to other amide local anaesthetics used for regional anaesthesia.
These data did not indicate any specific drug interactions that would require special study for the use of Naropin as a single dose or for treatment for less than 24 hours. Furthermore, drugs metabolised by CYP1A2, e.g. paracetamol, have also been used in combination with Naropin in the clinical program without clinical evidence of metabolic interactions. (See Pharmacokinetics.)

Adverse Effects

Adverse events reported in association with Naropin are similar in character to those observed with other local anaesthetics of the amide type.
Adverse reactions may be due to high plasma levels as a result of excessive dosage, rapid absorption, delayed elimination or metabolism, or inadvertent intravascular injection. They should be distinguished from the physiological effects of the nerve block itself, e.g. a decrease in blood pressure and bradycardia during epidural and intrathecal anaesthesia and events caused by needle puncture (e.g. spinal haematoma, postdural puncture, headache, meningitis and epidural abscess).
Pronounced acidosis, hyperkalaemia or hypoxia in the patient may increase the risk and severity of toxic reactions.
The effects of systemic overdose and unintentional intravascular injection may involve the central nervous system and/or the cardiovascular system (see Overdosage). Inadvertent subarachnoid injection may lead to CNS depression, respiratory arrest and cardiovascular collapse.

Very common events (> 10%).

Cardiovascular.

Hypotensionc.

Gastrointestinal.

Nausea.

Common events (> 1%).

A large number of adverse events have been reported during clinical development, the majority related to the expected effects of the block and to the clinical situation rather than reactions to the drug. Thus hypotension and nausea have been registered in 39% and 25%, respectively, of the patients treated in clinical studies.
The following adverse events are considered to be of clinical importance regardless of causal relationship.

Cardiovascular.

Bradycardiaa, hypertension and tachycardia.

Nervous system.

Paraesthesia, temperature elevation, rigors (chills), headachea and dizziness.

Gastrointestinal.

Vomitinga,d.

Other.

Urinary retentiona, back pain, insomnia, chest pain, pain and oliguria.

Uncommon events (≤ 1%).

Acute systemic toxicity.

More serious but less common reactions that reflect acute systemic toxicityb include dysarthria, muscular rigidity, muscle twitching, unconsciousness, convulsions, hypoxia, hypercapnia, apnoea, severe hypotension, bradycardia, arrhythmias and cardiac arrest. Indirect cardiovascular effects (hypotension, bradycardia) may occur after epidural administration, depending on the extent of the concomitant sympathetic block.
Convulsions, grand mal convulsions and seizures have been observed following unintended intravascular injection of Naropin.
Due to the low doses used for intrathecal anaesthesia, the potential for systemic toxic reactions is expected to be low.

Psychiatric.

Anxiety.

Nervous system.

Hypoaesthesiaa.

Vascular.

Syncopea.

Respiratory, thoracic and mediastinal.

Dyspnoeaa.

General disorders and administration site conditions.

Hypothermiaa.

Rare (≤ 0.1%).

Cardiac disorders.

Cardiac arrest, cardiac arrhythmias.

General disorders and administration site conditions.

Allergic reactions (anaphylactoid reactions, angioneurotic oedema and urticaria).
a These reactions are more frequent after spinal anaesthesia.
b These symptoms usually occur because of inadvertent intravascular injection, overdose or rapid absorption.
c Hypotension is less frequent in children (> 1%).
d Vomiting is more frequent in children (> 10%).

Class related adverse drug reactions.

This section includes complications related to anaesthetic technique regardless of the local anaesthetic used.

Neurological complications.

Neuropathy and spinal cord dysfunctions, e.g. anterior spinal artery syndrome, arachnoiditis, cauda equina syndrome, have been associated with intrathecal and epidural anaesthesia.

Total spinal block.

Total spinal block may occur if an epidural dose is inadvertently administered intrathecally, or if a too large intrathecal dose is administered.

Fetal, neonatal and infant adverse events.

Clinical trials have been conducted in over 400 pregnant women using Naropin. These studies recorded all adverse events experienced by the baby in utero, peripartum or postpartum, regardless of causality to Naropin, other medications or other factors.

Common events (> 1%).

Cardiovascular.

Fetal distress, fetal tachycardia and fetal bradycardia.

Gastrointestinal.

Neonatal vomiting.

Respiratory.

Neonatal respiratory disorders and neonatal tachypnoea.

Other.

Neonatal fever and neonatal jaundice.

Uncommon events (< 1%).

Metabolic.

Fetal acidosis and neonatal hypoglycaemia.

Other.

Hypotonia, neonatal sepsis and low Apgar score.

Dosage and Administration

Naropin should only be used by or under the supervision of clinicians experienced in regional anaesthesia.
The presentations of Naropin injection solutions are intended for single use only. Any solution remaining from an opened container should be discarded.
The lowest dosage that results in effective anaesthesia should be used and should be based on the status of the patient and the type of regional anaesthesia intended. In general, surgical anaesthesia requires the use of higher concentrations and doses than those required for analgesia.

Adults and children above 12 years of age.

Table 3 is a guide to dosage. The clinicians's experience and knowledge of the patient's physical status are of importance when deciding the dose.
The appropriate concentration and volume for each procedure should be selected. The 1% (10 mg/mL) formulation is recommended for epidural anaesthesia in which a profound motor block is essential for surgery. There is no information available regarding the use of concentrations above 0.75% (7.5 mg/mL) for caesarean section. For further details of procedures please see current standard textbooks.

Note.

Careful aspiration before and during injection is recommended to avoid intravascular injection.

Test dose.

For epidural anaesthesia, or when a large dose is to be injected, a 3 to 5 mL test dose of a local anaesthetic solution, preferably containing adrenaline 5 microgram/mL (e.g. 3 mL of Xylocaine 2.0% with adrenaline 1:200,000) should be administered. Verbal contact and repeated monitoring of heart rate and blood pressure should be maintained for five minutes following the test dose after which, in the absence of signs of subarachnoid, intravascular or intrathecal injection, the main dose may be administered.
An inadvertent intravascular injection may be recognised by a temporary increase in heart rate, and an accidental intrathecal injection by signs of a spinal block.
Prior to and during administration of the total dose, aspiration should be repeated. The main dose should be injected slowly at a rate of 25 to 50 mg/minute, while closely observing the patient's vital functions and maintaining verbal contact. If toxic symptoms or signs occur, the injection should be stopped immediately.
Intrathecal injections should be made after the subarachnoid space has been identified and clear cerebrospinal fluid (CSF) is seen to escape from the spinal needle, or is detected by aspiration.

Analgesia.

When calculating the dosage for postoperative analgesia, the use of intraoperative local anaesthetic(s) should be taken into account. For treatment of postoperative pain, the following technique can be recommended.
Epidural analgesia is maintained with a Naropin 0.2% (2 mg/mL) infusion. Infusion rates of 6 to 14 mL (12 to 28 mg)/hour provide adequate analgesia with only slight and nonprogressive motor block in most cases of moderate to severe postoperative pain.
With this technique a significant reduction in the need for opioids has been observed.
Clinical experience supports the use of Naropin 0.2% (2 mg/mL) epidural infusions for up to 72 hours. Data for peripheral nerve block administered as a continuous peripheral infusion or intermittent injections support the use for up to 48 hours only at dosages of 10 to 20 mg/hour (5 to 10 mL/hour).
When prolonged epidural blocks are used, either by continuous infusion or repeated bolus administration, the risks of reaching a toxic plasma concentration or inducing local neural injury must be considered. Cumulative doses of up to ropivacaine 800 mg for surgery and postoperative analgesia administered over 24 hours were well tolerated in adults, as were postoperative continuous epidural infusions at rates up to 28 mg/hour for 72 hours.
When prolonged peripheral nerve blocks are applied, either through continuous infusion or through repeated injections, the risk of reaching a toxic plasma concentration or inducing local neural injury must be considered.
In clinical studies, femoral nerve block was established with Naropin 0.75% (7.5 mg/mL) 300 mg and interscalene block with Naropin 0.75% (7.5 mg/mL) 225 mg, respectively, before surgery. Analgesia was then maintained with Naropin 0.2% (2 mg/mL). Infusion rates or intermittent injections of 10 to 20 mg/hour for 48 hours provided adequate analgesia and were well tolerated.

Use in children.


The doses in Table 4 should be regarded as guidelines for use in paediatrics. Individual variations occur. In children with a high bodyweight a gradual reduction of the dosage is often necessary and should be based on the ideal bodyweight. The volume for single caudal epidural block and the volume for epidural bolus doses should not exceed 25 mL in any patient. Standard textbooks should be consulted for factors affecting specific block techniques and for individual patient requirements.
Careful aspiration before and during injection is recommended to prevent intravascular injection. The patient's vital functions should be observed closely during the injection. If toxic symptoms occur, the injection should be stopped immediately.
A single caudal epidural injection of Naropin 0.2% (2 mg/mL) produces adequate postoperative analgesia below T12 in the majority of patients when a dose of 2 mg/kg is used in a volume of 1 mL/kg. In children above 4 years of age, doses up to 3 mg/kg have been used safely by the caudal route. The safety and efficacy of doses above 3 mg/kg have not been demonstrated and therefore cannot be recommended. The volume of the caudal epidural injection may be adjusted to achieve a different distribution to sensory block, as recommended in standard textbooks.
A single injection of Naropin 0.5% (5 mg/mL) at a dose of 2 mg/kg produces safe and effective analgesia when used for peripheral nerve block in children.
Fractionation of the calculated local anaesthetic dose is recommended, whatever the route of administration.
Use of Naropin in concentrations above 0.5% (5 mg/mL) has not been documented for children.
Intrathecal administration has not been documented for use in children.
The use of Naropin in premature children has not been documented.

Use in debilitated or elderly patients.

Debilitated or elderly patients, including those with partial or complete heart conduction block, advanced hepatic disease or severe renal dysfunction, should be given a reduced dosage commensurate with their physical condition. Clinical studies with this group of patients have not been performed (see Precautions).

Overdosage

Acute emergencies associated with the use of local anaesthetics are generally related to high plasma levels or to unintended subarachnoid injection of the local anaesthetic solution (see Adverse Effects and Precautions).
Accidental intravascular injections of local anaesthetics may cause immediate toxic effects. Toxic effects may also arise from exceptionally rapid absorption from highly vascularised areas. In the event of overdose, peak plasma concentrations may not be reached for one to two hours, depending on the site of injection, and signs of toxicity may thus be delayed. Systemic toxic reactions may involve the central nervous system and the cardiovascular system.
In children, as in adults, early signs of local anaesthetic toxicity may be difficult to detect in cases where the block is given during deep sedation or general anaesthesia.
After intrathecal administration, systemic toxicity is expected to be low, due to the low dose administered. However, an excessive dose administered into the intrathecal space may give rise to total spinal block.
Contact the Poisons Information Centre for advice on management of overdose.

Symptoms.

Central nervous system toxicity.

CNS toxicity is a graded response with symptoms and signs of escalating severity. Initially symptoms such as visual or hearing disturbances, perioral numbness, dizziness, lightheadedness, tingling and paraesthesia are seen. Dysarthria, muscular rigidity and muscular twitching are more serious and may precede the onset of generalised convulsions.
Unconsciousness and grand mal convulsions may follow, and can last from a few seconds to several minutes. Hypoxia and hypercapnia occur rapidly during convulsions due to the increased muscular activity, together with disruption to respiration and possible loss of functional airways. In severe cases apnoea may occur. Respiratory and metabolic acidosis, hyperkalaemia, hypocalcaemia and hypoxia increase and extend the toxic effects of local anaesthetics.
Recovery follows the redistribution of the local anaesthetic drug from the central nervous system and subsequent metabolism and excretion. Recovery should be rapid unless large amounts of the drug have been injected.

Cardiovascular toxicity.

Cardiovascular toxicity indicates a more severe situation. Hypotension, bradycardia, arrhythmia and even cardiac arrest may occur as a result of high systemic concentrations of local anaesthetics. In volunteers the intravenous infusion of Naropin resulted in signs of depression of conductivity and contractility.
Cardiovascular toxic effects are generally preceded by signs of toxicity in the central nervous system, unless the patient is receiving a general anaesthetic or is heavily sedated with drugs such as benzodiazepines or barbiturates. However, in rare cases, cardiac arrest has occurred without prodromal CNS effects.

Treatment.

If signs of acute systemic toxicity or total spinal block occur, injection of the local anaesthetic should be stopped immediately.
Treatment consists of ensuring adequate ventilation and arresting convulsions. Assisted or controlled ventilation should be maintained with oxygen, if required.
If convulsions occur and do not spontaneously stop within 15 to 20 seconds, an anticonvulsant should be given intravenously, e.g. diazepam 5 to 10 mg intravenously or, where indicated, sodium thiopentone (5 mg/kg). If convulsions interfere with breathing and/or are not rapidly controlled by specific anticonvulsant medication, suxamethonium (1 to 2 mg/kg) may be used to paralyse the patient. Artificial ventilation must then be instituted.
If cardiovascular depression is evident (hypotension, bradycardia), appropriate treatment with intravenous fluids, vasopressor and/or inotropic agents should be considered. Children aged between 0 and 12 years should be given doses commensurate with their age, weight and clinical status.
If ventricular fibrillation, cardiac arrest or circulatory arrest occur, cardiopulmonary resuscitation must be instituted and maintained. Optimal oxygenation, ventilation and circulatory support, as well as treatment of acidosis, are of vital importance.
Should cardiac arrest occur, prolonged resuscitative efforts may be required to improve the possibility of a successful outcome.

Compatibility and admixtures.

Naropin solution for infusion in plastic infusion bags (Polybag) is chemically and physically compatible with fentanyl citrate, morphine sulfate and clonidine hydrochloride.
The additive concentrations for Naropin 0.1 to 0.2% (1 to 2 mg/mL) are as follows: fentanyl citrate 1.0 to 10.0 microgram/mL; morphine sulfate 20.0 to 100.0 microgram/mL and clonidine hydrochloride 5.0 to 50.0 microgram/mL.
Chemical and physical stability of these mixtures have been demonstrated for 30 days at up to 30°C. To reduce microbiological hazard, these admixtures should be used immediately. If not used immediately, store at 2 to 8°C for not more than 24 hours.

Presentation

Injection (sterile, isotonic, isobaric, aqueous, preservative free solution), 0.2% (2 mg/mL): 10 mL, 20 mL, 100 mL, 200 mL; 0.5%* (5 mg/mL): 10 mL, 20 mL; 0.75% (7.5 mg/mL): 10 mL, 20 mL; 1% (10 mg/mL): 10 mL, 20 mL.
Naropin Polybag (100 and 200 mL) and Polyamp DuoFit (10 and 20 mL) presentations are in an AstraZeneca Theatre Pack.
*Not currently marketed in Australia.

Storage

Naropin Polyamp presentations must be stored below 30°C. Do not freeze.
Naropin Polybag presentations must be stored below 30°C. Do not freeze.
Polybag and Polyamp must not be re-autoclaved.

Poison Schedule

S4.