atropine sulfate monohydrate: clinical use

Prescribing considerations

• Administer under medical supervision and tailor use to clinical response and tolerability.
• Do not allow administration to delay external pacing in unstable high-grade atrioventricular block.
• Use additional caution in older people and in renal or hepatic impairment.
• Consider tachyarrhythmia, heart failure, coronary disease, hyperthyroidism, fever, gastrointestinal hypomotility and reduced bronchial secretions.
• In myasthenia gravis, avoid unless accompanying an anticholinesterase where clinically appropriate.

Contraindications and cautions

• Hypersensitivity to atropine or an excipient
• Closed-angle glaucoma
• Risk of urinary retention due to prostatic or urethral disease
• Achalasia, paralytic ileus or toxic megacolon
• These contraindications may not apply during life-threatening bradyarrhythmia or poisoning.

Monitoring

• Heart rate, rhythm, blood pressure and clinical response
• Mental state, temperature and ability to sweat
• Airway status and consequences of reduced bronchial secretions
• Urinary retention and gastrointestinal hypomotility
• Antimuscarinic toxicity, particularly in older people or with interacting medicines

Clinical pharmacology

Atropine is a tertiary-amine competitive muscarinic antagonist with peripheral and central effects. It increases sinus rate and sinoatrial or atrioventricular conduction, reduces exocrine and respiratory secretions, decreases gastrointestinal motility and inhibits bladder contraction. It crosses the blood–brain and placental barriers, is partly metabolised in the liver and is eliminated in urine unchanged and as metabolites.

Formulation and product differences

• Clear, colourless intravenous solution in a sterile pre-filled syringe without a needle.
• Licensed for adults only; its graduations are unsuitable for accurate paediatric measurement.
• Single-use, contains sodium and must not be mixed with other medicines.

Injection

Route: Parenteral

Strengths: 0.5 mg/5 mL, 1 mg/5 mL, 3 mg/10 mL