Consumer medicine information

DBL Promethazine Hydrochloride Injection BP

Promethazine hydrochloride

BRAND INFORMATION

Brand name

DBL Promethazine Hydrochloride Injection BP

Active ingredient

Promethazine hydrochloride

Schedule

What is in this leaflet

This leaflet answers some common questions about DBL™ Promethazine Hydrochloride Injection BP (Promethazine). It does not contain all the available information.

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

All medicines have risks and benefits. Your doctor has weighed the risks of you being given DBL™ Promethazine Hydrochloride Injection BP against the benefits they expect it will have for you.

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

Keep this leaflet in a safe place. You may need to read it again.

What DBL™ Promethazine Hydrochloride Injection BP is used for

This medicine is used to treat

allergic reactions,
to relieve nausea, vomiting and dizziness
as a sedative (to help people go to sleep and control their anxiety) before and after surgery, and during labour.

This medicine belongs to a group of antihistamines called phenothiazines (fen-oh-THY-ah-zines). It works by preventing the effects of histamine in the body.

Ask your doctor if you have any questions about why this medicine has been prescribed for you. Your doctor may have prescribed it for another reason.

This medicine is not addictive.

It is available only with a doctor's prescription.

Before you are given DBL™ Promethazine Hydrochloride Injection BP

When you must not be given it

You must not be given promethazine if you have an allergy to:

any medicine containing promethazine hydrochloride
any other phenothiazine-derivative antihistamines
any of the ingredients listed at the end of this leaflet, such as sulfites.

Some of the symptoms of an allergic reaction may include shortness of breath, wheezing or difficulty breathing; swelling of the face, lips or tongue or other parts of the body; rash, itching or hives on the skin.

This medicine must not be given to children under the age of 2 years. Safety and effectiveness in children under the age of 2 years, have not been established.

You must not use this medicine after the expiry date printed on the pack or if the packaging is torn or shows signs of tampering. If it has expired or is damaged return it to your pharmacist for disposal.

If you are not sure whether you should be given this medicine, talk to your doctor.

Before you are given it

Tell your doctor if you have any allergies to any other medicines, foods, preservatives or dyes.

Tell your doctor if you have or have had any of the following medical conditions:

asthma or breathing difficulties
bone-marrow depression
enlarged prostate
epilepsy
heart or blood pressure disease
irregular heart beat
glaucoma, an eye condition
liver problems
ulcer of the stomach or duodenum
kidney or bladder problems

Tell your doctor if you are pregnant or plan to become pregnant. DBL™ Promethazine Hydrochloride Injection BP is not recommended for use during later stages of pregnancy. If there is a need to consider promethazine during pregnancy, your doctor will discuss with you the benefits and risks of being given it.

Tell your doctor or pharmacist if you are breast-feeding or plan to breast-feed. Promethazine passes into breast milk and there is a possibility that your baby may be affected. Your doctor or pharmacist will discuss the possible risks and benefits of being given promethazine while you are breast-feeding.

If you have not told your doctor about any of the above, tell him/her before you are given promethazine.

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including medicines that you get without a prescription from your pharmacy, supermarket or health food shop.

Some medicines and promethazine may interfere with each other. These include:

anticholinergic medicines, including medicines for stomach spasm
anticonvulsants or medicines for epilepsy/fits/seizures
beta blockers such as propranolol, medicines used to lower blood pressure
bromocriptine, a medicine used to treat Parkinson's disease, acromegaly or to prevent lactation
central nervous system depressants (medicines that cause drowsiness or sleepiness) such as sedatives, tranquillisers, barbiturates, antihistamines, general anaesthetics and alcohol
levodopa (medicine for Parkinson's disease)
metrizamide, a contrast agent, injected into the spinal cord before an x-ray
monoamine oxidase (MAO) inhibitors (medicine for depression)
phenothiazines (medicine for thought disorder)
quinidine, a medicine for rapid or irregular heartbeat
medicines to treat cold and flu
appetite suppressants
tricyclic antidepressants (medicine for depression)

These medicines may be affected by promethazine or may affect how well it works. You may need different amounts of your medicine, or you may need to take different medicines.

Your doctor or pharmacist has more information on medicines to be careful with or avoid while being treated with this medicine.

Use in children

In general, children are more sensitive to the effects of antihistamines, and DBL™ Promethazine Hydrochloride Injection BP should be administered with caution. Serious side effects, such as convulsions, are more likely to occur in younger patients and would be of greater risk to infants than to older children or adults. Also, nightmares or unusual excitement, nervousness, restlessness, or irritability may be more likely to occur in children.

The use of this medicine is not recommended in children who have a history of difficulty in breathing while sleeping or a family history of sudden infant death syndrome (SIDS), or in children under 2 years of age.

Children or adolescents who show signs of Reye's syndrome should not be given this medicine. Uncontrolled movements that may occur with Promethazine may be mistakenly confused with symptoms of Reye's syndrome.

How DBL™ Promethazine Hydrochloride Injection BP is given

How much is given

Your doctor will decide what dose you will receive. This depends on your condition and other factors, such as your weight.

How it is given

Promethazine is given as

a deep injection into a large muscle or
as a slow injection into a vein.

It must only be given by a doctor or nurse.

If you receive too much (overdose)

As DBL™ Promethazine Hydrochloride Injection BP is given to you under the supervision of your doctor, it is unlikely that you will receive an overdose. However, if you experience severe side effects tell your doctor immediately, or contact the Poisons Information Centre for advice. (In Australia, call 13 11 26; in New Zealand call 0800 764 766.) or go to Accident and Emergency at the nearest hospital, You may need urgent medical attention.

Symptoms of an overdose may include the side effects listed in the 'Side Effects' section but are usually of a more severe nature.

Ask your doctor or pharmacist if you have any concerns.

While you are being given DBL™ Promethazine Hydrochloride Injection BP

Things you must do

If you are about to start taking any new medicine, tell your doctor and pharmacist that you are being given DBL™ Promethazine Hydrochloride Injection BP.

Tell any other doctors, dentists, and pharmacists who treat you that you are being given this medicine.

If you are going to have surgery, tell the surgeon or anaesthetist that you are being given this medicine. It may affect other medicines used during surgery.

If you are about to have any blood tests, tell your doctor that you are being given this medicine. It may interfere with the results of some tests including pregnancy, glucose and skin allergen tests.

Things you must not do

Do not give this medicine to anyone else, even if they have the same condition as you.

Do not use this medicine to treat any other complaints unless your doctor tells you to.

Things to be careful of

Be careful driving or operating machinery until you know how promethazine affects you. This medicine may cause drowsiness, dizziness or sleepiness in some people. If you have any of these symptoms, do not drive, operate machinery or do anything else that could be dangerous. Children should be careful when riding bicycles or climbing trees.

Be careful when drinking alcohol while being given this medicine. If you drink alcohol, dizziness or drowsiness may be worse.

Use a sunscreen on exposed skin or remain covered if you go outdoors after being given promethazine. This medicine may cause you to sunburn more easily.

Side Effects

Tell your doctor or nurse as soon as possible if you do not feel well while you are being given promethazine. This medicine helps most people, but it may have unwanted side effects in a few people. All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical attention if you get some of the side effects.

If you are over 65 years of age you may have an increased chance of getting side effects.

Do not be alarmed by the following lists of side effects. You may not experience any of them.

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

Tell your doctor, nurse or pharmacist if you notice any of the following and they worry you:

nausea and vomiting
constipation or diarrhea
loss of appetite
sore throat and fever
unusual bleeding or bruising
unusual tiredness or weakness
clumsiness or unsteadiness
severe drowsiness
severe dryness or mouth nose or throat
feeling faint
hallucinations
restlessness
shuffling walk
trembling and shaking of hands
difficulty in sleeping
skin itch

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

tremors or convulsions
blurred vision
confusion
difficult or painful urination
fast or slow heartbeat
trouble breathing
skin rash
muscle spasms in the neck and back,
jerky movements of the head and face
flushing or redness of face
unusual excitement, nervousness, restlessness or irritability
ringing or buzzing in ears
severe pain in the stomach with bloating, gut cramps and vomiting

These may be serious side effects. You may need urgent medical attention.

Tell your doctor, nurse or pharmacist if you notice anything that is making you feel unwell. Other side effects not listed above may also occur in some people. Some side effects may only be found when your doctor does tests from time to time to check your progress.

After being given DBL™ Promethazine Hydrochloride Injection BP

Storage

DBL™ Promethazine Hydrochloride Injection BP will be stored in the pharmacy or on the ward. The injection is kept in a cool dry place, protected from light, where the temperature stays below 25°C.

Product description

What it looks like

DBL™ Promethazine Hydrochloride Injection BP is a clear, colourless solution.

Ingredients

DBL™ Promethazine Hydrochloride Injection BP contains 50 mg/ 2 mL of promethazine hydrochloride as the active ingredient.

It also contains:

disodium edetate
acetic acid
sodium acetate
sodium metabisulfite
water for injections.

This medicine does not contain gluten, lactose, sucrose, tartrazine or any other azo dyes.

Sponsor

DBL™ Promethazine Hydrochloride Injection BP is supplied by:

Australian Sponsor:

Pfizer Australia Pty Ltd
Sydney NSW
Toll Free Number: 1800 675 229
www.pfizer.com.au

AUST R 16255

This leaflet was updated in April 2019

Published by MIMS July 2019

BRAND INFORMATION

Brand name

DBL Promethazine Hydrochloride Injection BP

Active ingredient

Promethazine hydrochloride

Schedule

1 Name of Medicine

Promethazine hydrochloride.

2 Qualitative and Quantitative Composition

Each mL of the solution contains 25.0 mg promethazine hydrochloride, 0.10 mg disodium edetate, 1.30 microlitre glacial acetic acid, 27.2 mg sodium acetate and 1.32 mg sodium metabisulfite in water for injections.

Excipient(s) with known effect.

Sodium metabisulfite.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Solution for injection.
DBL Promethazine Hydrochloride Injection BP is a clear, colourless solution of pH 5.0 to 6.0.

4 Clinical Particulars

4.1 Therapeutic Indications

DBL Promethazine Hydrochloride Injection BP is indicated for the following conditions:
Treatment of allergic reactions such as: uncomplicated allergic conditions of the immediate type, e.g. pruritus, urticaria and angioedema, when oral therapy is impossible or contraindicated.
Treatment and prevention of vomiting including: motion sickness; drug induced nausea; prevention and control of nausea and vomiting associated with certain types of anaesthesia and surgery, such as procedures with a high incidence of post-operative vomiting (e.g. gynaecological surgery, strabismus or middle ear surgery, and electroconvulsive therapy); in patients with a past history of motion sickness or post-operative vomiting; and in patients in whom avoidance of vomiting is crucial (e.g. neurosurgery and eye surgery).
Promethazine has sedative effects and it is also used in: pre-operative, post-operative and obstetric (during labour) sedation.

4.2 Dose and Method of Administration

Dosage.

Allergic conditions.

Adults.

25 mg to 50 mg by deep intramuscular injection or slow intravenous injection; may be repeated within two hours if necessary. Maximum dose up to 150 mg daily.
Antiemetic. Antiemetics should not be used in vomiting of unknown etiology in children and adolescents (see Section 4.4 Special Warnings and Precautions for Use).
In established nausea or vomiting due to causes other than motion sickness.

Adults.

12.5 to 25 mg, by intramuscular or intravenous injection, every four hours as needed.

Children.

5 to 12 yrs old - 12.5 mg by intramuscular injection.
Sedative/hypnotic.

Adults.

25 to 50 mg by intramuscular or intravenous injection.

Children.

When oral route is not possible;
2 to 5 yrs old - 7.5 to 10 mg by intramuscular injection.
6 to 10 yrs old - 10 to 12.5 mg by intramuscular injection.
Pre-operative and post-operative sedation.

Adults.

25 to 50 mg by intramuscular or intravenous injection, usually with pethidine and atropine.
Obstetric sedation. Early stages of labour: 50 mg, by intramuscular injection. Established labour: 25 to 75 mg, by intramuscular or intravenous injection, with an appropriately reduced dose of an opioid analgesic. May be repeated once or twice at four hourly intervals during the course of the labour, if necessary. Total dose should not exceed 100 mg in 24 hours.

Method of administration.

All routes of administration can cause damage to tissues (see Section 4.3 Contraindications; Section 4.4 Special Warnings and Precautions for Use).
Deep Intramuscular Injection is the preferred route of administration of DBL Promethazine Hydrochloride Injection BP.
Promethazine should only be administered intravenously if the benefits outweigh the risks in an individual patient. This may include emergency situations or situations where IM injections are contraindicated (see Section 4.4 Special Warnings and Precautions for Use). Extreme care must be taken to avoid extravasation or intra-arterial injection. Injections should be stopped immediately if a patient complains of pain during injection (see Section 4.4 Special Warnings and Precautions for Use).
If venous administration is required, a large vein should be used. Administration via a venous site in the hand or wrist should be avoided if possible due to an increased risk of tissue injury.
When given intravenously, DBL Promethazine Hydrochloride Injection BP 50 mg/2 mL should be diluted 1 in 10 with water for injections or preferably given through the tubing of a freely flowing IV infusion. It should be injected slowly at a rate of administration not greater than 25 mg/minute (i.e. 10 mL/minute of dilute solution).
Rapid intravenous infusion may cause a transient fall in blood pressure and may increase the risk of severe tissue injuries. Promethazine should not be given intra-arterially or subcutaneously (see Section 4.3 Contraindications).

4.3 Contraindications

Promethazine is contraindicated for use in paediatric patients less than two years of age because of the potential for fatal respiratory depression. Post marketing cases of respiratory depression including fatalities have been reported with the use of promethazine in paediatric patients less than two years of age. A wide range of weight-based doses of promethazine have resulted in respiratory depression in these patients (see Section 4.4 Special Warnings and Precautions for Use).
Promethazine is contraindicated in patients who have exhibited hypersensitivity to the drug or other phenothiazine derivatives.
Promethazine is also contraindicated in the following patients: comatose; after administration of large doses of other CNS depressants (e.g. alcohol, general anaesthetics, opioid analgesics, tranquillisers, etc.).
Intra-arterially administration of DBL Promethazine Hydrochloride Injection BP is contraindicated due to the likelihood of severe arteriospasm and the possibility of resultant gangrene.
Subcutaneous administration of DBL Promethazine Hydrochloride Injection BP is contraindicated, as the solution is an irritant and may produce necrotic lesions.

4.4 Special Warnings and Precautions for Use

This product should not be used in children under 2 years of age due to the potential for fatal respiratory depression (see Section 4.3 Contraindications).
Antiemetics are not recommended for treatment of uncomplicated vomiting in paediatric patients, and their use should be limited to prolonged vomiting of known etiology.
As a result of its anticholinergic actions, promethazine should be used with caution in patients with narrow-angle glaucoma, prostatic hypertrophy, stenosing peptic ulcer, pyloroduodenal obstruction, and bladder neck obstruction. It should also be used with caution in patients with bone marrow depression, jaundice, impaired liver function, epilepsy, asthmatic attack, or cardiovascular disorders.
Promethazine may mask the adverse effects of ototoxic medications, e.g. tinnitus, dizziness. Concurrent use of promethazine and other hypotension producing medications may produce additive hypotensive effects. Concurrent use of promethazine with other hepatotoxic medications may increase the potential for hepatotoxicity, and patients should be carefully monitored.
Promethazine's antiemetic action may mask the symptoms of acute appendicitis or overdose of other drugs.
QT interval prolongation has been reported with phenothiazines.
The concomitant administration of alcohol, sedative-hypnotics, general anaesthetics, opioids, tranquillisers or other CNS depressants may have an additive sedative effect. Patients should be warned accordingly.
DBL Promethazine Hydrochloride Injection BP contains sodium metabisulfite, which may cause allergic type reactions, including anaphylactic symptoms and life threatening or less severe asthmatic episodes, in certain susceptible people.

Intravenous use.

Promethazine is highly caustic to the intima of blood vessels and surrounding tissues. Intravenous administration can cause severe tissue injury including gangrene, which may require surgical intervention including fasciotomy, skin graft, and/or amputation. Severe tissue injury may result from perivascular extravasation, unintentional intra-arterial injection, and intraneuronal or perineuronal infiltration. Prescribes should be aware of early sign of tissue injury including burning or pain at the injection site, phlebitis, swelling and blistering. Injections should be stopped immediately if any of these symptoms occur.
If venous administration is required, a large vein should be used. Administration via a venous site in the hand or wrist should be avoided if possible due to an increased risk of tissue injury.

Use in the elderly.

No data available.

Paediatric use.

Caution should be exercised when administering promethazine to paediatric patients two years of age or older, because the potential for fatal respiratory depression, including central and obstructive apnoea and reduced arousal. Respiratory depression and apnoea, sometimes fatal, are associated with promethazine even if individualised weight-based dosing is used. It is recommended that the lowest effective dose of promethazine be used in paediatric patients 2 years of age and older and concomitant administration of other drugs with respiratory depressant effects be avoided.
Use of promethazine should be avoided in acutely ill or dehydrated children, since these patients have an increased susceptibility to dystonias. Use of the drug should also be avoided in children and adolescents with signs and symptoms which suggest Reye's syndrome, since the potential extrapyramidal effects produced by the drug may obscure the diagnosis of, or be confused with the CNS signs and symptoms of this condition or other hepatic diseases. Excessively large doses in children may cause hallucinations, convulsions and sudden death. Children may experience paradoxical excitation with promethazine.

Effects on laboratory tests.

Promethazine may interfere with diagnostic pregnancy tests based on immunological reactions between HCG and anti-HCG, and may cause an increase in glucose tolerance. Promethazine may produce false negative results in skin tests using allergen extracts. It is recommended that antihistamines are discontinued at least 72 hours before testing begins.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Anticholinergics.

Anticholinergic effects may be potentiated when these medications are used concurrently with promethazine. Patients should be advised to report occurrence of gastrointestinal problems promptly, since paralytic ileus may occur with concurrent therapy.

Anticonvulsants.

As promethazine may lower the convulsion threshold, dosage adjustment of anticonvulsant medication may be required.

Antihypertensive agents.

Concurrent use of promethazine with beta blockers, especially propranolol, may result in increased plasma concentrations of each agent because of inhibition of metabolism. This may result in additive hypotensive effects, irreversible retinopathy, cardiac arrhythmias and tardive dyskinesia.
The neuronal uptake of guanethidine may be inhibited when used with promethazine, causing a decrease in the antihypertensive effect.

Bromocriptine.

Increase serum prolactin concentrations, thereby interfering with the effects of bromocriptine. Dosage adjustments of bromocriptine may be necessary.

CNS depressants.

Promethazine may potentiate the sedative action of other CNS depressants such as barbiturates, antihistamines, tranquillisers, opioids, general anaesthetics, or alcohol.

Levodopa.

The antiparkinsonian effects of levodopa may be inhibited when used concurrently with promethazine because of blockade of dopamine receptors in the brain.

Metrizamide.

Concurrent use of intrathecal metrizamide with promethazine may lower the seizure threshold. Promethazine should be discontinued at least 48 hours before, and not resumed for at least 24 hours following myelography.

Monoamine oxidase (MAO) inhibitors.

Concurrent use of MAO inhibitors with promethazine may prolong and intensify the anticholinergic and CNS depressant effects, and may increase the risk of hypotension and extrapyramidal reactions.

Phenothiazine derivatives.

Concurrent use of other phenothiazine derivatives may increase the severity and frequency of extrapyramidal effects.

Quinidine.

Concurrent use of promethazine with quinidine may result in additive cardiac effects.

Sympathomimetic agents.

The alpha adrenoceptor agonist effects of adrenaline may be blocked when it is used concurrently with promethazine, possibly resulting in severe hypotension and tachycardia. The alpha adrenoceptor blocking activity of promethazine may also decrease the pressor response to ephedrine, metaraminol and methoxamine; decrease the stimulant effects of amphetamines; and antagonise the anorectic effect of the centrally acting appetite suppressants.

Tricyclic antidepressants.

Concurrent use of tricyclic antidepressants may intensify the anticholinergic effects and increase the risk of hypotension and extrapyramidal effects.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

No data available.
(Category C¹)
When given in high doses during late pregnancy, phenothiazines have caused prolonged extrapyramidal disturbances in the child.
¹Category C: Drugs which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible.
The exact amount of promethazine excreted into breast milk is unknown, but amounts are usually small. Promethazine should be used with caution in nursing women. The infant should be observed for side effects, especially sedation.

4.7 Effects on Ability to Drive and Use Machines

Promethazine may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks such as driving a vehicle or operating machinery.

4.8 Adverse Effects (Undesirable Effects)

CNS.

Sedation is the most prominent CNS effect of promethazine. Extrapyramidal reactions may occur with high doses and usually subside with dosage reduction. Other reported reactions include dizziness, lassitude, tinnitus, confusion, disorientation, incoordination, fatigue, blurred vision, euphoria, diplopia, nervousness, irritability, tremors, convulsions, oculogyric crises, excitation, catatonic-like states, and hysteria.

Cardiovascular.

Tachycardia, bradycardia, faintness, dizziness, transient minor increases in blood pressure, and hypotension have been reported following the use of DBL Promethazine Hydrochloride Injection BP. Venous thrombosis at the injection site has been reported.

Gastrointestinal.

Nausea and vomiting have been reported, usually in association with surgical procedures and combination drug therapy. Loss of appetite, epigastric distress, constipation and diarrhoea have also been reported.

Allergic.

Urticaria, dermatitis, pruritus, asthma, photosensitivity, and angioneurotic oedema have been reported.

Other reported reactions.

Leukopenia and agranulocytosis, usually when promethazine has been used in association with other known toxic agents; anaphylaxis; thrombocytopenic purpura; obstructive jaundice; tissue necrosis following subcutaneous injection; nasal stuffiness; and dry mouth.

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at www.tga.gov.au/reporting-problems.

4.9 Overdose

Symptoms.

Symptoms of overdose range from mild depression of the CNS and cardiovascular system (drowsiness, bradycardia, tachycardia, and transient increases in blood pressure) to profound hypotension, respiratory depression, and unconsciousness. Paradoxical CNS stimulation (hallucinations, seizures, nightmares and trouble in sleeping) may be evident, especially in children and the elderly. Anticholinergic symptoms (severe dryness of mouth, nose or throat, flushing or redness of face, trouble in breathing), and extrapyramidal effects (muscle spasms, especially of the neck and back, restlessness, tic-like movements of head and face, trembling of hands) may occur.

Treatment.

Treatment of promethazine overdosage is similar to that of other phenothiazine derivatives. Symptomatic supportive therapy is indicated and general physiologic measures such as maintenance of adequate ventilation should be instituted if necessary. Analeptics may cause convulsions and should not be used. Convulsions may be controlled with diazepam or barbiturates. Anticholinergic antiparkinsonism agents may be used to treat severe extrapyramidal reactions. Severe hypotension may respond to administration of noradrenaline or phenylephrine, but should not be treated with adrenaline because it may lower the blood pressure further.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

Promethazine is a phenothiazine derivative with potent antihistaminic and sedative-hypnotic effects. It also has antiemetic, antivertigo, anti-motion sickness, anticholinergic effects and local anaesthetic actions.
Antihistamines competitively and reversibly antagonise the effects of histamine at the H₁-receptor sites on effector cells which are responsible for vasodilatation, increased capillary permeability, flare and itch reactions in the skin, and to some extent for contraction of smooth muscle in the bronchi and gastrointestinal tract.
The precise mechanism of the CNS effects of promethazine is unknown. The sedative effects may involve antagonism at central histamine, serotonin and acetylcholine receptors, or central alpha adrenergic stimulation. However, paradoxical CNS stimulation may occur, especially in children, and at high doses may be attributable to antimuscarinic activity. The antiemetic, anti-motion sickness and antivertigo effects of promethazine are possibly a result of central anticholinergic actions on the vestibular apparatus and the integrative vomiting centre and medullary chemoreceptive trigger zone of the midbrain.
The anticholinergic (antimuscarinic) actions of promethazine provide a drying effect on the oral and nasal mucosa.

Clinical trials.

No data available.

5.2 Pharmacokinetic Properties

Promethazine is well absorbed from parenteral sites and the onset of antihistaminic properties occurs about 20 minutes after intramuscular injection and 3 to 5 minutes after intravenous injection. It has a prolonged antihistamine action, which may persist for 12 hours or more. The duration of sedative effects may range from 2 to 8 hours depending on the dose and route of administration.
Promethazine is widely distributed within body tissues. Promethazine crosses the blood-brain barrier, and the placenta and is excreted in breast milk. It is metabolised by the liver and excreted slowly in the urine and faeces mainly as inactive promethazine sulphoxide and glucuronides; elimination half lives of 7 to 14 hours have been reported.

5.3 Preclinical Safety Data

Genotoxicity.

No data available.

Carcinogenicity.

No data available.

6 Pharmaceutical Particulars

6.1 List of Excipients

Disodium edetate, glacial acetic acid, sodium acetate, sodium metabisulfite, water for injections.

6.2 Incompatibilities

Solutions of promethazine hydrochloride are incompatible with alkaline substances which precipitate the insoluble promethazine base. Promethazine has been reported to be incompatible with solutions containing the following compounds: aminophylline, benzylpenicillin salts, cefepime hydrochloride, cefotetan disodium, cephazolin, chloramphenicol sodium succinate, chloroquine phosphate, chlorothiazide sodium, dexamethasone sodium phosphate, dextran, dimenhydrinate, flucloxacillin sodium, foscarnet, frusemide, heparin sodium, hydrocortisone sodium succinate, ketorolac tromethamine, meglumine diatrizoate, meglumine iodipamide, methicillin sodium, methohexitone sodium, methotrexate sodium, morphine sulfate, nalbuphine hydrochloride (some formulations only), nitrofurantoin, penicillin G, pentobarbitone sodium, phenobarbitone sodium, phenytoin sodium, piperacillin, sodium bicarbonate, sodium diatrizoate, sodium iothalamate, sulphafurazole, thiopentone sodium.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Store below 25°C. Protect from light.

6.5 Nature and Contents of Container

DBL Promethazine Hydrochloride Injection BP is available as follows:

Strength.

50 mg/2 mL.

Pack.

5 x 2 mL coloured glass ampoules.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of in accordance with local requirements.

6.7 Physicochemical Properties

Molecular formula: C₁₇H₂₀N₂S.HCl. Molecular weight. 320.9.

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DBL Promethazine Hydrochloride Injection BP

Promethazine hydrochloride

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