Consumer medicine information

Atropine Injection BP

Atropine sulfate monohydrate

BRAND INFORMATION

Brand name

Bridgewest Atropine Injection BP

Active ingredient

Atropine sulfate monohydrate

Schedule

S4

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Atropine Injection BP.

SUMMARY CMI

Atropine Injection BP

Consumer Medicine Information (CMI) summary

The full CMI on the next page has more details. If you are worried about using this medicine, speak to your doctor or pharmacist.

1. Why am I given Atropine Injection?

Atropine Injection contains the active ingredient atropine sulfate monohydrate. Atropine Injection is given before anaesthesia to decrease mucus secretions, such as saliva. During anaesthesia and surgery, atropine is used to help keep the heart beat normal. Atropine Injection is also used to block or reverse the adverse effects caused by some medicines and certain types of pesticides.

For more information, see Section 1. Why am I given Atropine Injection? in the full CMI.

2. What should I know before receiving Atropine Injection?

Do not use if you have ever had an allergic reaction to atropine, or any of the anticholinergic medicines such as hyoscyamine and belladonna.

Talk to your doctor if you have any other medical conditions, take any other medicines, or are pregnant or plan to become pregnant or are breastfeeding.

For more information, see Section 2. What should I know before receiving Atropine Injection? in the full CMI.

3. What if I am taking other medicines?

Some medicines may interfere with Atropine Injection and affect how it works.

A list of these medicines is in Section 3. What if I am taking other medicines? in the full CMI.

4. How is Atropine Injection given?

Atropine Injection will be given to you by a doctor or nurse as an injection under the skin, into the muscle or directly into the blood stream.

More information can be found in Section 4. How is Atropine Injection given? in the full CMI.

5. What should I know after receiving Atropine Injection?

Driving or using machines
  • Be careful before you drive or use any machines or tools until you know how Atropine Injection affects you. Atropine Injection may cause drowsiness or blurred vision in some people

For more information, see Section 5. What should I know after receiving Atropine Injection? in the full CMI.

6. Are there any side effects?

Common side effects are blurred vision, dilation of pupils, difficulty in urinating, constipation, fever, flushing, dryness of skin, headache, dizziness, drowsiness and/or weakness, nervousness, restlessness, confusion, unusual excitement shaking and/or tremor, nausea, vomiting, fast and/or irregular heartbeat, loss of taste, dryness of the mouth, nose and throat, thirst.

For more information, including what to do if you have any side effects, see Section 6. Are there any side effects? in the full CMI.



FULL CMI

Atropine Injection BP

Active ingredient(s): atropine sulfate monohydrate


Consumer Medicine Information (CMI)

This leaflet provides important information about using Atropine Injection. You should also speak to your doctor or pharmacist if you would like further information or if you have any concerns or questions about receiving Atropine Injection.

Where to find information in this leaflet:

1. Why am I given Atropine Injection?
2. What should I know before receiving Atropine Injection?
3. What if I am taking other medicines?
4. How is Atropine Injection given?
5. What should I know after receiving Atropine Injection?
6. Are there any side effects?
7. Product details

1. Why am I given Atropine Injection?

Atropine Injection contains the active ingredient atropine sulfate monohydrate. Atropine sulfate monohydrate belongs to a group of medicines called antimuscarinic agents.

Atropine Injection is given before anaesthesia to decrease mucus secretions, such as saliva. During anaesthesia and surgery, atropine is used to help keep the heart beat normal. Atropine Injection is also used to block or reverse the adverse effects caused by some medicines and certain types of pesticides.

2. What should I know before receiving Atropine Injection?

Warnings

You must not be given Atropine Injection if:

  • you are allergic to atropine, or have had an unusual reaction to atropine or any of the anticholinergic medicines such as hyoscyamine and belladonna.
    Always check the ingredients to make sure you can use this medicine.
  • you have or have had any medical conditions, especially the following:
    - severe and chronic inflammation of the large intestine and rectum
    - gastrointestinal blockage and/or diseases
    - enlarged prostate
    - urinary tract blockage and/or bladder problems
    - fever, or if you are exposed to very high temperatures
    - glaucoma and/or family history of glaucoma
    - myasthenia gravis (severe muscle weakness)
    - acute bleeding, especially if you have heart problems
    - heart disease
    - high blood pressure due to pregnancy
    - overactive thyroid.

If you are not sure whether any of these apply to you, check with your doctor.

Check with your doctor if you:

  • have or have had any medical conditions, especially the following:
    - brain damage and/or mental confusion
    - lung diseases
    - liver and/or kidney diseases
    - hormone problems
    - high blood pressure
    - fast heart beat
    - hiatus hernia
    - heart diseases
    - stomach and intestinal problems
    - gastric ulcer, diarrhoea or gastrointestinal infection.
  • take any medicines for any other condition.

During treatment, you may be at risk of developing certain side effects. It is important you understand these risks and how to monitor for them. See additional information under Section 6. Are there any side effects?

Pregnancy and breastfeeding

Tell your doctor if you are pregnant or plan to become pregnant or are breast-feeding. Your doctor can discuss with you the risks and benefits involved.

3. What if I am taking other medicines?

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

Some medicines and atropine sulfate monohydrate may interfere with each other. These include:

  • medicines to treat irregular heartbeat e.g. disopyramide and quinidine
  • blood "thinning" medicines e.g., heparin, warfarin
  • medicines to treat Parkinson's disease
  • metoclopramide, a medicine to treat nausea and vomiting
  • cisapride, a medicine used in certain stomach problems
  • anticholinergic medicines to prevent travel sickness, relieve stomach cramps or spasms
  • antispasmodics
  • bethanechol, a medicine used in bladder function disorders
  • antihistamines
  • medicines to treat depression such as tricyclic antidepressants
  • medicines used to treat certain mental and emotional conditions
  • ketoconazole, a medicine to treat fungal infections
  • narcotic analgesics to treat severe pain
  • medicines used for glaucoma e.g. pilocarpine, carbachol
  • medicines to treat Alzheimer's disease e.g. rivastigmine and donepezil
  • muscle relaxants used during an operation.

If you are to receive Atropine Injection as a premedication, your doctor will advise if you should continue to take your regular medicines.

Check with your doctor if you are not sure about what medicines, vitamins or supplements you are taking and if these affect Atropine Injection.

4. How is Atropine Injection given?

How much is given

Your doctor will decide what dose and how often you will receive Atropine Injection. The dosage you will be given will depend on your condition, what it is being used for and other factors, such as your age, and whether or not other medicines are being given at the same time.

How is it given

Atropine Injection will be given to you by a doctor or nurse as an injection under the skin, into the muscle or directly into the blood stream.

If you are given too much

This rarely happens as Atropine Injection will be given to you in hospital under the care of a highly trained doctor.

In the unlikely event that you are given too much (an overdose), you may experience some of the effects listed under Section 6. Are there any side effects?

The signs of overdose are dilation of the pupils, difficulty in swallowing, hot dry skin, thirst, dizziness, flushing and inability to pass urine. Rapid breathing, increased heart rate, tremor, fatigue, loss of muscle control, confusion, hallucinations, paranoid, hyperactivity and occasional seizures or convulsions may also occur.

Your doctor has information on how to recognise and treat an overdose. Ask your doctor if you have any concerns.

5. What should I know after receiving Atropine Injection?

Things you should do

Tell your doctor or nurse if you do not feel well after you have been given Atropine Injection.

Driving or using machines

Be careful before you drive or use any machines or tools until you know how Atropine Injection affects you.

Atropine Injection may cause drowsiness or blurred vision in some people.

Looking after your medicine

Atropine Injection is usually stored in the hospital, clinic or at the pharmacy.

Your doctor, pharmacist or nurse is responsible for storing Atropine Injection in a cool dry place, where the temperature stays below 25°C and disposing of any unused product correctly.

6. Are there any side effects?

All medicines can have side effects. If you do experience any side effects, most of them are minor and temporary. However, some side effects may need medical attention.

See the information below and, if you need to, ask your doctor or pharmacist if you have any further questions about side effects.

Possible side effectsWhat to do
  • blurred vision and/or discomfort in the eyes especially if your eyes are more sensitive to light than normal, dilation of pupils
  • difficulty in urinating
  • constipation
  • fever
  • flushing, dryness of skin
  • skin rash, hives
  • headache, dizziness, drowsiness and/or weakness
  • nervousness, restlessness, confusion, unusual excitement shaking and/or tremor
  • nausea, vomiting
  • fast and/or irregular heart beat
  • loss of taste
  • dryness of the mouth, nose and throat, thirst
Tell your doctor or nurse if you notice any of these side effects or they worry you.

Tell your doctor or nurse if you notice anything else that may be making you feel unwell.

Other side effects not listed here may occur in some people.

Reporting side effects

After you have received medical advice for any side effects you experience, you can report side effects to the Therapeutic Goods Administration online at www.tga.gov.au/reporting-problems. By reporting side effects, you can help provide more information on the safety of this medicine.

7. Product details

This medicine is only available with a doctor's prescription.

What Atropine Injection contains

Active ingredient
(main ingredient)
  • atropine sulfate monohydrate (600 micrograms in 1 mL or 1200 micrograms in 1 mL)
Other ingredients
(inactive ingredients)
  • sodium chloride
  • water for Injections
It does not contain preservatives.

Tell your doctor if you are allergic to any of these ingredients.

What Atropine Injection looks like

Atropine Injection is a clear, colourless solution in a plastic ampoule.

Atropine Injection BP 600 micrograms in 1 mL is available in packs of 10 or 50 ampoules (Aust R 11302)

Atropine Injection BP 1200 microgram in 1 mL is available in packs of 50 ampoules (Aust R 11303)

* Not all presentations and pack sizes may be marketed.

Who manufactures and distributes Atropine Injection

Bridgewest Perth Pharma Pty Ltd
15 Brodie Hall Drive
Bently WA 6102
Telephone: 1800 161 156
[email protected]

This leaflet was prepared in September 2023.

Published by MIMS November 2023

BRAND INFORMATION

Brand name

Bridgewest Atropine Injection BP

Active ingredient

Atropine sulfate monohydrate

Schedule

S4

 

1 Name of Medicine

Atropine sulfate monohydrate.

2 Qualitative and Quantitative Composition

Atropine Injection BP is a sterile, isotonic, preservative free solution containing 600 micrograms of atropine sulfate monohydrate in 1 mL or 1200 micrograms of atropine sulfate monohydrate in 1 mL.

3 Pharmaceutical Form

Solution for injection.
Clear, colourless solution.

4 Clinical Particulars

4.1 Therapeutic Indications

Preanaesthetic medication to reduce salivary secretions and bronchial secretions.
To prevent cholinergic cardiac effects such as cardiac arrhythmias, hypotension and bradycardia.
Management of patients with acute myocardial infarction and sinus bradycardia who have associated hypotension and increased ventricular irritability.
Concurrent administration with anticholinesterase agents (e.g. neostigmine, physostigmine) to block the adverse muscarinic effects of these agents following surgery to terminate curarisation.
For poisoning by organophosphate pesticides, atropine may be used concomitantly with a cholinesterase reactivator such as pralidoxime to reverse muscarinic effects.

4.2 Dose and Method of Administration

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Do not administer unless solution is clear and seal is intact.
Atropine Injection may be given by subcutaneous (SC), intramuscular (IM), or direct intravenous (IV) injection.
Atropine Injection should not be added to any IV infusion solutions for administration. Atropine Injection contains no microbial agent. It should be used in one patient on one occasion only and any residue discarded.

Cardiopulmonary resuscitation.

The usual adult dose is 0.4-1 mg IV, which may be repeated at 5 minute intervals until the desired heart rate is achieved. The total dose should not exceed 2 mg.
The usual paediatric dose is 0.02 mg/kg (maximum single dose 0.5 mg) IV, which may be repeated at 5 minute intervals until the desired heart rate is achieved. The total dose should not exceed 1 mg.

Premedication.

300-600 microgram atropine injection may be given IM or SC 30 to 60 minutes prior to induction of anaesthesia, usually in conjunction with a narcotic. Alternatively 300-600 microgram IV may be given immediately before induction of anaesthesia.
Suitable premedication doses to be given SC 30 to 60 minutes prior to surgery in infants and children are:
infants < 3 kg: 100 microgram;
7 to 9 kg: 200 microgram;
12 to 16 kg: 300 microgram;
20 to 27 kg: 400 microgram;
32 kg: 500 microgram;
41 kg: 600 microgram.

Reversal of competitive neuromuscular block.

May be given by slow IV injection in conjunction with an anticholinesterase agent (e.g. neostigmine, physostigmine). Six hundred microgram (600 microgram) - 1.2 mg atropine for each 0.5 - 2.5 mg neostigmine methylsulfate in adults and 0.02 mg/kg atropine for each 0.04 mg/kg neostigmine methylsulfate in children.

Organophosphate poisoning.

1-2 mg atropine may be given IV. Additional 2 mg doses may be administered IM or IV every 5 to 60 minutes until muscarinic signs and symptoms subside, and repeated if these reappear. For severe cases, 2-6 mg may be administered IV, with subsequent additional doses of 2-6 mg being administered IM or IV every 5 to 60 minutes until muscarinic signs and symptoms subside.
Doses up to 50 mg may be required within the first 24 hours. With severe cases atropine therapy should be withdrawn gradually to avoid sudden recurrence of symptoms (e.g. pulmonary oedema). A cholinesterase reactivator (e.g. pralidoxime) is administered concomitantly.
The dose for children is 0.05 mg/kg IM or IV repeated at 10 to 30 minute intervals until muscarinic signs and symptoms subside. This is to be repeated if these reappear.

4.3 Contraindications

Known hypersensitivity to atropine or other anticholinergic agents.
Severe ulcerative colitis.
Toxic megacolon complicating ulcerative colitis.
Gastrointestinal obstruction, e.g. pyloroduodenal stenosis, achalasia, cardiospasm, paralytic ileus, intestinal atony.
Closed angle glaucoma.
Obstructive uropathy, e.g. bladder neck obstruction caused by prostatic hypertrophy.
Myasthenia gravis.
Tachycardia secondary to cardiac insufficiency or thyrotoxicosis.
Acute haemorrhage with unstable cardiovascular status.
Febrile patients or patients exposed to elevated ambient temperature, due to the risk of provoking hyperpyrexia and heat prostration.
Prostatic enlargement.
Pregnancy induced hypertension.

4.4 Special Warnings and Precautions for Use

Atropine should be used with caution in all patients and especially those over 40 years old as they may be more susceptible to its adverse effects.
Atropine should be used with caution in patients with hyperthyroidism, hepatic or renal disease, hypertension, severe heart disease, ulcerative colitis, ileus, chronic pulmonary disease, or autonomic neuropathy, prostatic hypertrophy, oesophageal reflux or hiatus hernia.

Cardiovascular status.

Atropine should be used with caution in conditions characterised by tachycardia, such as cardiac insufficiency or failure (see Section 4.3 Contraindications), acute myocardial infarction or ischaemia and in cardiac surgery where it may further accelerate the heart rate. Tachycardia may result from vagal inhibition and induce angina pectoris in patients with coronary heart disease. When the recurrent use of atropine is essential in patients with coronary artery disease, the total dose should not exceed 2 mg (see Section 4.2 Dose and Method of Administration) to avoid the detrimental effects of atropine-induced tachycardia on myocardial oxygen demand.
Atropine has been associated with the development of arrhythmias in adult and paediatric patients. Accelerated heart rate and intraventricular conduction delays have been associated with the development of ventricular fibrillation.

Mental confusion.

Atropine may cause mental confusion, especially in elderly or brain damaged patients.

Debilitated patient.

Caution is required in administering atropine to debilitated patients, especially with chronic pulmonary disease, since reduced bronchial secretions may cause inspissation and bronchial viscid plugs formation.

Gastrointestinal.

Since atropine decreases gastrointestinal motility, it should be used with caution in patients with gastric ulcer, oesophageal reflux, known or suspected gastrointestinal infections, e.g. Clostridium difficile associated diarrhoea and colitis (antibiotic associated pseudomembranous colitis), incomplete intestinal obstruction or ulcerative colitis. Atropine should also be used with caution in patients with diarrhoea, since diarrhoea may be an early symptom of incomplete intestinal obstruction, especially in patients with ileostomy or colostomy.
Atropine may convert partial organic pyloric stenosis into complete obstruction.

Glaucoma.

Systemic administration of conventional doses of atropine may precipitate acute glaucoma in susceptible individuals.

Use in the elderly.

Atropine should be used with caution in geriatric patients since they may be more susceptible to its adverse effects. Elderly patients may react with excitement, agitation, drowsiness or confusion to even small doses of atropine. Changes in dosage should be gradual. Memory may become severely impaired in geriatric patients, especially those who already have memory problems, with the continued use of anticholinergics since these drugs block the actions of acetylcholine, which is responsible for many functions of the brain, including memory functions.
In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

Paediatric use.

Atropine should be used with caution in infants and small children since they may be more susceptible to its adverse effects. It should be used with caution in patients with Down's syndrome and children with spastic paralysis or brain damage as they may be hypersensitive to the effects of atropine.

Effects on laboratory tests.

No data available.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Atropine may cause increased anticholinergic activity when administered concomitantly with other anticholinergic drugs such as phenothiazines, antispasmodics, antiparkinsonian drugs, antiarrhythmics with anticholinergic activity, e.g. disopyramide and quinidine, some antihistamines, tricyclic antidepressants or butyrophenones.
The absorption of other drugs may be affected by the reduction in gastric motility caused by atropine.
Atropine antagonises the actions of a number of compounds, including synthetic choline esters, e.g. bethanechol and carbachol, anticholinesterase drugs, e.g. physostigmine, neostigmine and pyridostigmine, and cholinomimetic alkaloids e.g. pilocarpine.

Ketoconazole.

Anticholinergics may increase gastrointestinal pH, possibly resulting in a marked reduction in ketoconazole absorption during concurrent use with anticholinergics; patients should be advised to take these medications at least 2 hours after ketoconazole.

Cisapride and metoclopramide.

Concurrent use with anticholinergics may antagonise the gastrointestinal motility of cisapride and metoclopramide.

Opioid (narcotic) analgesics.

Concurrent use with anticholinergics may result in increased risk of severe constipation, which may lead to paralytic ileus and/or urinary retention.

Haloperidol.

Antipsychotic effectiveness of haloperidol may be decreased in schizophrenic patients.

Cholinesterase inhibitors.

In view of the pharmacodynamic effects of atropine, atropine may interfere with the activity of cholinesterase inhibitors such as rivastigmine, donepezil.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

Studies have not been done in either animals or humans to evaluate the potential of atropine to impair fertility.
(Category A)
Atropine has been used in a large number of pregnant women and women of childbearing age without an increase in the frequency of malformations or other direct or indirect harmful effects on the foetus having been observed. However, proven safety of atropine in pregnancy has not been established. As with all drugs, caution is essential in the use of atropine in pregnant women. Atropine crosses the placental barrier and may cause tachycardia in the foetus.
Atropine inhibits lactation. It is reported to distribute into breast milk in small quantities. Since some infants can be sensitive to atropine, and atropine may cause antimuscarinic effects in the infant, use of atropine during breastfeeding is not recommended.

4.7 Effects on Ability to Drive and Use Machines

Since antimuscarinics may cause drowsiness or blurred vision, patients should be warned not to engage in activities requiring mental alertness and/or visual acuity (e.g. driving a car or operating machinery).

4.8 Adverse Effects (Undesirable Effects)

Most side effects are directly related to the antimuscarinic actions of atropine. Adverse effects following single or repeated doses are most often the result of excessive dosage.

More common reactions.

Cardiovascular.

Tachycardia and palpitations. Atropine blocks vagal impulses with consequent increase in heart rate with possible atrial arrhythmias, atrioventricular dissociation, multiple ventricular ectopics and angina.

Central nervous system.

Xerostomia, thirst, dryness of the mouth. These are due to the reduction of salivary, bronchial and sweat secretions and are dose related.

Gastrointestinal.

Constipation due to the inhibition of parasympathetic control of the GI tract.

Genitourinary.

Urinary difficulty and retention due to inhibition of parasympathetic control of the bladder.

Ocular.

Dilatation of the pupils (mydriasis) with loss of accommodation (cycloplegia), blurred vision, photophobia can occur with increasing doses of atropine.

Dermatological.

Flushing, dryness of the skin.

Less common reactions.

Cardiovascular.

The development of angina in patients with known cardiac problems has been reported.

Central nervous system.

Tremor, headache, nervousness, drowsiness, weakness, insomnia, fatigue, ataxia, hyperpyrexia, dizziness, confusion and/or excitement.
Anhidrosis also may occur and can produce heat intolerance in patients living in a hot environment.

Gastrointestinal.

Nausea, vomiting, retrosternal pain due to increased gastric reflux.

Dermatological.

Hypersensitivity reactions may manifest as conjunctivitis or skin rash which, in some instances, progresses to exfoliation and various dermal manifestations.

Ocular.

Increased ocular tension.

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

There is considerable patient variability in the susceptibility to atropine. Atropine overdosage is characterised by both peripheral and central symptoms. Toxic doses cause dilated pupils, difficulty in swallowing, hot dry skin, thirst, dizziness, vasodilation, urinary retention, tachycardia, rapid respiration, hyperpyrexia, and central nervous system stimulation marked by restlessness, tremor, fatigue, ataxia, confusion, excitement, paranoid psychotic reactions, delirium, hallucinations and occasionally seizures or convulsions. A rash may appear on the face or upper trunk. In severe toxicity, CNS stimulation may give way to CNS depression, coma, circulatory and respiratory failure and death. following paralysis and coma. In addition to tachycardia, cardiac manifestations may include ECG abnormalities (e.g. ventricular arrhythmias, extrasystoles) resulting from enhanced re-entrant excitation secondary to reduced conduction velocity. Widening of the QRS complex, prolongation of the QT interval and ST segment depression may also be seen.

Treatment.

Symptomatic and supportive therapy should be provided. Close monitoring, including ECG monitoring, is recommended. Fluid therapy and other standard treatments for shock should be administered. Hyperthermia should be treated with cold packs, mechanical cooling devices or sponging with tepid water. Maintenance of adequate airway is essential, with respiratory assistance if necessary. Urinary catheterisation may be required if the patient is comatose. If photophobia occurs, the patient may be kept in a dark room.
The use of physostigmine as an antidote for atropine poisoning is controversial due to the potential for physostigmine to produce severe adverse effects, e.g. seizures, asystole. The use of physostigmine should be reserved for treatment of patients with extreme delirium or agitation, patients with repetitive seizures, patients with severe sinus tachycardia or supraventricular tachycardia or unresponsive extreme hyperthermia in patients who fail to respond to alternative therapy. Physostigmine should not be used to treat cardiac conduction defects or ventricular tachyarrhythmias. IV propranolol may be useful for treatment of supraventricular tachyarrhythmias unresponsive to physostigmine or where physostigmine is contraindicated.
Relative contraindications to the use of physostigmine include asthma, gangrene, cardiovascular disease and mechanical obstruction of the gastrointestinal or genitourinary tract. In such patients physostigmine should only be used where a life threatening emergency occurs.
Diazepam may be administered to control excitement, delirium or other symptoms of acute psychosis. Phenothiazines should be avoided since these may exacerbate antimuscarinic effects.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Class: Anticholinergic agent.

Mechanism of action.

Atropine is often classified as an anticholinergic drug but is more accurately described as an antimuscarinic agent since it competitively inhibits the muscarinic actions of acetylcholine and has both peripheral and central actions. It reduces secretions, especially salivary and bronchial secretions, and also reduces perspiration. It has little effect on intestinal, biliary or pancreatic secretions since these secretions are principally controlled by hormonal rather than vagal mechanisms.
Atropine has activity both on structures innervated by postganglionic cholinergic nerves and on smooth muscles which respond to endogenous acetylcholine but are not so innervated. As with other antimuscarinic agents, the major action of atropine is a competitive or surmountable antagonism which can be overcome by increasing the concentration of acetylcholine at receptor sites of the effector organ (e.g. by using anticholinesterase agents which inhibit the enzymatic destruction of acetylcholine). The receptors antagonised by atropine in therapeutic doses are primarily the peripheral structures that are stimulated or inhibited by muscarine (i.e. exocrine glands and smooth and cardiac muscle). Responses to postganglionic cholinergic nerve solution may also be inhibited by atropine but this occurs less readily than with responses to injected (exogenous) choline esters.
Atropine induced parasympathetic inhibition may be preceded by a transient phase of stimulation, especially on the heart where small doses first slow the rate before characteristic tachycardia develops due to paralysis of vagal control. Atropine exerts a more potent and prolonged effect on the heart, intestine and bronchial muscle than hyoscine, but its action on the iris, ciliary body and certain secretory glands is weaker than that of hyoscine. Atropine has an antispasmodic action on smooth muscle and diminishes gastric and intestinal motility.
Atropine has central nervous system (CNS) activity. Average doses (400 microgram-1 mg) produce stimulation of the medulla and higher cerebral centres, causing mild vagal excitation. The increased respiratory rate and sometimes, increased depth of respiration produced by atropine are more probably the result of bronchiolar dilation. Accordingly, atropine is an unreliable respiratory stimulant and large or repeated doses may depress respiration.
Adequate doses of atropine abolish various types of reflex vagal cardiac slowing or asystole. The drug also prevents or abolishes bradycardia or asystole produced by injection of choline esters, anticholinesterase agents or other parasympathetic drugs, and cardiac arrest produced by stimulation of the vagus. Larger doses cause prominent central excitation, blocking the vagus nerve resulting in restlessness, irritability, disorientation, hallucinations or delirium.
Atropine Injection in therapeutic doses counteracts the peripheral dilatation and abrupt decrease in blood pressure produced by choline esters. However, when given by itself, atropine does not exert a striking or uniform effect on blood vessels or blood pressure. Systemic doses slightly raise systolic and lower diastolic pressures and can produce significant postural hypotension. Such doses also slightly increase cardiac output and decrease central venous pressure. Occasionally, therapeutic doses dilate the cutaneous blood vessels, particularly in the "blush" area (atropine flush), and may cause atropine "fever" due to suppression of sweat gland activity in infants and small children.

Clinical trials.

No data available.

5.2 Pharmacokinetic Properties

Absorption.

Atropine is well absorbed following intramuscular administration, and peak plasma concentrations are reached within 30 minutes accompanied by an increase in heart rate which reaches a maximum at 15 to 50 minutes. The duration of effect on the heart rate is reported to be up to five hours. Inhibition of salivation occurs within 30 minutes, peaks within 1-2 hours and persists for 4 hours following intramuscular administration. Increased heart rate occurs within 5-40 minutes and peaks within 20 minutes to 1 hour after intramuscular administration. With intravenous administration, increased heart rate effect peaks within 2-4 minutes. Low doses of the drug cause a paradoxical decrease in heart rate. Following intravenous infusion, serum levels of atropine drop rapidly within the first ten minutes and then decrease more gradually. One hour after either intramuscular or intravenous injection, atropine levels are very similar.

Distribution.

Atropine is well distributed throughout the body. It crosses the blood brain barrier and also the placental barrier and is distributed into milk in small quantities. It has a large apparent volume of distribution (2 to 4 L/kg) and shows a high interindividual variability in serum protein binding.

Metabolism.

Atropine is metabolised in the liver to several metabolites and excreted mainly in the urine. Approximately 30-50% of a dose is excreted in the urine unchanged. Small amounts of atropine may also be eliminated in expired air as carbon dioxide and in faeces.

Excretion.

Atropine has a plasma half-life of 2-3 hours. Following intramuscular administration elimination appears biphasic with an initial phase of about 2 hours and a half-life in the terminal phase of 12.5 hours or longer. In children, the plasma half-life is approximately 6.5 hours.

5.3 Preclinical Safety Data

Genotoxicity.

Studies have not been undertaken in either animals or humans to evaluate the mutagenic potential of atropine.

Carcinogenicity.

Studies have not been undertaken in either animals or humans to evaluate the potential of atropine.

6 Pharmaceutical Particulars

6.1 List of Excipients

Sodium chloride, water for injections.

6.2 Incompatibilities

Atropine Injection has been shown to be incompatible with solutions containing adrenaline hydrochloride, amylobarbitone sodium, pentobarbitone sodium, promazine hydrochloride, ampicillin sodium, chloramphenicol sodium succinate, chlortetracycline hydrochloride, heparin sodium, metaraminol tartrate, methicillin sodium, nitrofurantoin, novobiocin, oxacillin sodium, sodium bicarbonate, sulfadiazine sodium, sulfafurazole diethanolamine, tetracycline hydrochloride, thiopentone sodium, vitamin B complex with ascorbic acid and warfarin sodium. This list is not exhaustive.

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. Single use only. Discard unused portion.

6.5 Nature and Contents of Container

Atropine Injection BP is supplied as 1 mL LDPE ampoules in packs of 50 or 10 (AUST R 11302 only) ampoules.
Not all pack sizes may be marketed.

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

Atropine sulfate monohydrate is bis (1R,3r,5S) -3-[(RS) -(3-hydroxy-2- phenylpropionyl)oxy]-8-methyl-8- azabicyclo[3.2.1]octane sulfate. It appears as colourless crystals or a white crystalline powder. It is very soluble in water, freely soluble in alcohol and practically insoluble in ether.

Chemical structure.


Molecular formula: (C17H23NO3)2,H2SO4,H2O.
Molecular weight: 695.

CAS number.

5908-99-6.

7 Medicine Schedule (Poisons Standard)

Prescription Only Medicine - S4.

Summary Table of Changes