ATROPT 1% eye drops

MIMS Revision Date: 01 September 2025

1 Name of Medicine

Atropine sulfate monohydrate.

2 Qualitative and Quantitative Composition

Atropt 1% eye drops contain atropine sulfate monohydrate (1%) in a sterile ophthalmic solution.
List of excipients with known effect. Benzalkonium chloride.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Atropt 1% eye drops are a clear or almost clear, odourless, slightly viscous, colourless liquid which foams on shaking.

4 Clinical Particulars

4.1 Therapeutic Indications

Atropt 1% eye drops are indicated where it is necessary to dilate the pupil and paralyse accommodation.

4.2 Dose and Method of Administration

Instil one drop into the eye as required for treatment. To minimise the risk of systemic absorption, gentle pressure should be applied to the tear duct for one minute after application.

4.3 Contraindications

Atropt 1% eye drops are contraindicated in the presence of angle closure glaucoma or where angle closure glaucoma is suspected. If used in glaucoma susceptible patients, an estimation of the depth of the angle of the anterior chamber should be performed prior to the initiation of therapy.
Hypersensitivity to any of the ingredients of Atropt 1% eye drops.

4.4 Special Warnings and Precautions for Use

Patients treated prior to ophthalmic examination should be escorted to and from the surgery.
Risk benefit should be considered when the following medical problems exist: keratoconus (atropine may produce fixed dilated pupil), synechiae between the iris and lens.
Use in the elderly. Geriatric patients are more susceptible to the effects of atropine, thus increasing the potential for systemic side effects.
Paediatric use. Atropt 1% must not be used in children less than 2 years old as it contains boron which may impair fertility in the future.
Atropine sulfate monohydrate should not be used in children who have previously had severe systemic reaction to atropine. An increased susceptibility to atropine has been reported in infants and young children and in children with blonde hair, blue eyes, Down's syndrome, spastic paralysis, or brain damage; therefore atropine should be used with great caution in these patients.
Effects on laboratory tests. No data available.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Anticholinergics. If significant systemic absorption of ophthalmic atropine occurs, concurrent use of other anticholinergics or medications with anticholinergic activity may result in potentiated anticholinergic effects.
Antiglaucoma agents. (Cholinergic, long acting, ophthalmic). Concurrent use with atropine may antagonise the antiglaucoma and miotic actions of ophthalmic long acting cholinergic antiglaucoma agents such as echothiophate. Concurrent use with atropine may also antagonise the anti-accommodative convergence effects of these medications when they are used for the treatment of strabismus.
Antimyasthenics, potassium citrate, potassium supplements. If significant systemic absorption of ophthalmic atropine occurs, concurrent use may increase the chance of toxicity and/or side effects of these systemic medications because of the anticholinergic induced slowing of gastrointestinal motility.
Carbachol, physostigmine or pilocarpine. Concurrent use with atropine may interfere with the antiglaucoma action of carbachol, physostigmine or pilocarpine. Also, concurrent use may counteract the mydriatic effect of atropine; this counteraction may be used to therapeutic advantage.
CNS depression producing medications. If significant absorption of systemic atropine occurs, concurrent use of medications having CNS effects, such as antiemetic agents, phenothiazines, or barbiturates, may result in opisthotonos, convulsions, coma, and extrapyramidal symptoms.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility. No data available. Excipients containing boron such as boric acid or borate compounds have been shown to cause reduced fertility and effects on embryofoetal development in animal studies and this appears to be dose related. The relevance of this to humans is uncertain.
Use in pregnancy. (Category A)
Atropine sulfate monohydrate may be systemically absorbed after ocular administration, however significant effects on the foetus have not been reported.
Use in lactation. Systemically absorbed atropine sulfate monohydrate is distributed into breast milk in very small amounts. It may cause adverse effects, such as rapid pulse, fever, or dry skin, in nursing infants of mothers using ophthalmic atropine.

4.7 Effects on Ability to Drive and Use Machines

The pupil dilation will last for up to 12 days. This can make driving or using machinery difficult and possibly hazardous. Patients should be advised not to drive or operate hazardous machinery until vision is clear.

4.8 Adverse Effects (Undesirable Effects)

The following adverse reactions have been reported.
Ophthalmic. Blurred vision, local irritation, follicular conjunctivitis, vascular congestion, oedema, exudate, contact dermatitis, eczematous dermatitis.
Systemic. Systemic atropine toxicity may be manifest as flushing and dryness of the skin, blurred vision, rapid and irregular pulse, fever, abdominal distension in infants, mental aberration and loss of neuromuscular coordination. Severe systemic reactions to atropine are characterised by hypotension with progressive respiratory depression. Ophthalmic atropine has been associated with cardiac arrhythmias (e.g. atrial fibrillation) in a few patients.
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

Signs of overdosage are similar to those described as systemic effects (see Section 4.8 Adverse Effects (Undesirable Effects)). Treatment is symptomatic and supportive.
For systemic effects, 0.2 to 1 mg (0.2 mg in children) physostigmine should be administered intravenously, as a dilution containing 1 mg in 5 mL of normal saline. The solution should be injected over a period of not less than 2 minutes. Dosage may be repeated every 5 minutes up to a total dose of 2 mg in children and 6 mg in adults in each 30 minute period. Physostigmine is contraindicated in hypertensive reactions. ECG monitoring is recommended during physostigmine administration.
Excitement may be controlled by diazepam or a short acting barbiturate.
It is recommended that 1 mg of atropine be available for immediate injection if the physostigmine causes bradycardia, convulsion, or bronchoconstriction.
Supportive therapy may require oxygen and assisted respiration; cool water baths for fever, especially in children; and catheterisation for urinary retention. In infants and small children, the body surface should be kept moist.
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. Atropine is a belladonna alkaloid. Atropine sulfate monohydrate acts in the eye to block the action of acetylcholine, relaxing the cholinergically innervated sphincter muscle of the iris. This results in dilation of the pupil (mydriasis). The cholinergic stimulation of the accommodative ciliary muscle of the lens is also blocked. This results in paralysis of accommodation (cycloplegia).
Atropine sulfate monohydrate has a slower onset and more prolonged effects than most other anticholinergics. Maximum mydriatic effect occurs in around 30 to 40 minutes. Maximum cycloplegia takes several hours. Mydriasis usually lasts 7 to 12 days and cycloplegia persists for 14 days or longer. Onset of effects and duration may be prolonged in heavily pigmented eyes.
Clinical trials. No data available.

5.2 Pharmacokinetic Properties

Absorption. Atropine is readily absorbed from the gastrointestinal tract; it is also readily absorbed from mucous membranes, the eye, and to some extent through intact skin.
Distribution. It is rapidly cleared from the blood and is distributed throughout the body. It crosses the blood brain barrier.
Metabolism. It is incompletely metabolised in the liver.
Excretion. It is excreted in the urine as unchanged drug and metabolites. A half-life of 4 hours has been reported.

5.3 Preclinical Safety Data

Genotoxicity. Studies have not been performed in either animals or humans to evaluate the potential mutagenic effects of atropine.
Carcinogenicity. Studies have not been performed in either animals or humans to evaluate the potential carcinogenic effects of atropine.

6 Pharmaceutical Particulars

6.1 List of Excipients

Disodium edetate, benzalkonium chloride, hypromellose, boric acid and water for injections.

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

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.
Discard 4 weeks after opening.

6.5 Nature and Contents of Container

15 mL PE-dropper bottles fitted with a PP tamper evident eye drop cap.

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 exists as odourless, colourless crystals or white crystalline powder. It effloresces in dry air. It is soluble in water (1 in 0.5), in boiling water (1 in 2.5), in alcohol (1 in 5), in glycerol (1 in 2.5), and is practically insoluble in chloroform and ether. A 2% solution in water has a pH of 4.5 to 6.2. Solutions may be sterilised by autoclave. Atropine sulfate monohydrate should be protected from light.
Chemical structure. Atropine sulfate monohydrate is both a mydriatic and cycloplegic has the following chemical structure:

It has a molecular formula of (C₁₇H₂₃NO₃)₂.H₂SO₄.H₂O and a molecular weight of 694.8.
CAS number. CAS - 55-48-1 (anhydrous); CAS - 5908-99-6 (monohydrate).

7 Medicine Schedule (Poisons Standard)

Prescription only medicine: S4.

Date of First Approval

14 October 1991

Date of Revision

29 July 2025

Summary Table of Changes