Atropine sulfate is a naturally occurring tertiary amine antimuscarinic agent, derived from the deadly nightshade plant (Atropa belladonna). It is a competitive antagonist of acetylcholine at postganglionic muscarinic receptors in the parasympathetic nervous system. The 0.6mg strength is a standard pre-anesthetic dose used to inhibit salivation and bronchial secretions, prevent bradycardia, and block vagal reflexes. In the Indian context, it is a critical, low-cost drug used extensively in anesthesia, emergency medicine (organophosphate poisoning), and ophthalmology.
Adult: Pre-anesthetic: 0.4-0.6 mg IM/IV/SC 30-60 min pre-op. Bradycardia (ACLS): 0.5-1 mg IV every 3-5 min, max 3 mg. Organophosphate poisoning: Initial 2-4 mg IV, then 2 mg every 5-60 min until atropinization (dry skin, tachycardia, mydriasis). Maintenance infusion often required.
Note: For IV use: Administer undiluted or diluted in 10ml normal saline. Give slowly over at least 1 minute. For IM/SC: Inject into a large muscle mass. For pre-op, give 30-60 min before induction. In organophosphate poisoning, administer until full atropinization is achieved and maintained.
Atropine competitively blocks the neurotransmitter acetylcholine at muscarinic receptors (M1, M2, M3, M4, M5) of postganglionic cholinergic nerves in the parasympathetic autonomic nervous system and in the central nervous system. This blockade inhibits the effects of parasympathetic (vagal) stimulation.
Pregnancy: Category C: Use only if clearly needed. Crosses placenta. May cause fetal tachycardia. Avoid in third trimester (may affect fetal heart rate monitoring).
Driving: May cause blurred vision, dizziness, or drowsiness. Patients should not drive or operate machinery until their vision is clear and they know how the drug affects them.
| Other Anticholinergics (e.g., antihistamines, TCAs, antipsychotics) | Additive anticholinergic side effects (dry mouth, constipation, confusion, urinary retention). | Major |
| Potassium Chloride (wax-matrix tablets) | Increased risk of GI mucosal lesions due to reduced motility. | Moderate |
| Digoxin | Increased serum digoxin levels due to reduced GI motility, risk of toxicity. | Moderate |
| Amantadine | Enhanced CNS toxicity and anticholinergic effects. | Moderate |
| Metoclopramide | Mutual antagonism of effects on GI motility. | Moderate |
| Ketoconazole, Antacids | Reduced absorption of these drugs due to altered GI pH and motility. | Moderate |
Same composition (Atropine (0.6mg)), different brands: