Atropine binds to and inhibit muscarinic acetylcholine receptors, producing a wide range of anticholinergic effects. Atropine is an anticholinergic agent which competitively blocks the muscarinic receptors in peripheral tissues such as the heart, intestines, bronchial muscles, iris and secretory glands. Some central stimulation may occur. Atropine abolishes bradycardia and reduces heart block due to vagal activity. Smooth muscles in the bronchi and gut are relaxed while glandular secretions are reduced. It also has mydriatic and cycloplegic effect.

Atropine is indicated for Non ulcer dyspepsia, Irritable bowel syndrome, Diverticular disease, Bradycardia, Organophosphorus poisoning, Premedication in anesthesia, Poisoning or overdosage with compound having muscarinic actions, Ophthalmic Inflammatory eye disorders, Eye refraction.

Adult:

• IV: Bradycardia: 500 mcg every 3-5 mins. Total: 3 mg.
• IV/IM: Organophosphorus poisoning: 2 mg every 10-30 mins until muscarinic effects disappear or atropine toxicity appears.
• IM/SC: Premedication in anesthesia: 300-600 mcg 30-60 mins before anesthesia.
• IV/IM/SC: Poisoning or overdosage with compound having muscarinic actions: 0.6-1 mg, repeat 2 hrly.
• Ophthalmic: Inflammatory eye disorders: As 0.5-1% solution: 1-2 drops 4 times/day.
• Ophthalmic: refraction: 1% solution 1 drop twice daily for 1-2 days before procedure.
• Oral: Non ulcer dyspepsia, Irritable bowel syndrome, Diverticular disease: 0.6-1.2 mg as a single dose at bedtime.

Usual Pediatric Dose for Anesthesia:

• 7 to 16 pounds: 0.1 mg, IV, IM, or subcutaneously
• 17 to 24 pounds: 0.15 mg, IV, IM, or subcutaneously
• 24 to 40 pounds: 0.2 mg, IV, IM, or subcutaneously
• 40 to 65 pounds: 0.3 mg, IV, IM, or subcutaneously
• 65 to 90 pounds: 0.4 mg, IV, IM, or subcutaneously
• Over 90 pounds: 0.4 to 0.6 mg, IV, IM, or subcutaneously

Glaucoma, chronic respiratory disease, sick sinus syndrome, thyrotoxicosis, cardiac failure, pyloric stenosis, prostatic hypertrophy.

Injection: Dry mouth, dysphagia, constipation, flushing and dryness of skin, tachycardia, palpitations, arrhythmias, mydriasis, photophobia, cycloplegia, raised intraocular pressure. Toxic doses cause tachycardia, hyperpyrexia, restlessness, confusion, excitement, hallucinations, delirium and may progress to circulatory failure and resp depression.

Eye drops or ointment: Systemic toxicity esp in children, on prolonged use may lead to irritation, hyperaemia, oedema and conjunctivitis. Increased intraocular pressure.

Overdose Effects

May cause hyperthermia, hypertension, increased respiratory rate, nausea and vomiting. May also lead to CNS stimulation. Severe intoxication may lead to CNS depression, coma, respiratory failure and death.

Reflux oesophagitis; elderly; infants and children; Pregnancy.

Pregnancy & Lactation

Pregnancy Category C. Animal reproduction studies have not been conducted with atropine. It also is not known whether atropine can cause fetal harm when given to a pregnant woman or can affect reproduction capacity. Atropine should be given to a pregnant woman only if clearly needed.