Atropine Sulfate

What it is and how it works

Mechanism of Action Atropine is an antimuscarinic agent since it antagonizes the muscarine-like actions of acetylcholine and other choline esters. Atropine inhibits the muscarinic actions of acetylcholine 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).

Indications

Atropine Sulfate Injection, USP, is indicated for temporary blockade of severe or life threatening muscarinic effects, e.g., as an antisialagogue, an antivagal agent, an antidote for organophosphorus or muscarinic mushroom poisoning, and to treat bradyasystolic cardiac arrest. Atropine is a muscarinic antagonist indicated for temporary blockade of severe or life threatening muscarinic effects.

Dosage and administration (summary)

For intravenous administration. . Titrate according to heart rate, PR interval, blood pressure and symptoms. Adult dosage Antisialagogue or for antivagal effects: Initial single dose of 0.5 to 1 mg. Antidote for organophosphorus or muscarinic mushroom poisoning: Initial single dose of 2 to 3 mg, repeated every 20 to 30 minutes. Bradyasystolic cardiac arrest: 1 mg dose, repeated every 3 to 5 minutes if asystole persists. Patients with Coronary Artery Disease: Limit the total dose to 0.03 mg/kg to 0.04 mg/kg. General Administration Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

Contraindications

None. None.

Warnings and precautions

Tachycardia Glaucoma Pyloric obstruction Worsening urinary retention Viscid bronchial plugs Tachycardia When the recurrent use of atropine is essential in patients with coronary artery disease, the total dose should be restricted to 2 to 3 mg (maximum 0.03 to 0.04 mg/kg) to avoid the detrimental effects of atropine-induced tachycardia on myocardial oxygen demand. Acute Glaucoma Atropine may precipitate acute glaucoma. Pyloric Obstruction Atropine may convert partial organic pyloric stenosis into complete obstruction.

Pregnancy

Pregnancy Pregnancy Risk Summary There are risks to the mother and fetus associated with untreated severe or life-threatening muscarinic events (see Clinical Considerations). Available data from published observational studies on atropine use in pregnant women are insufficient to evaluate for a drug-associated risk of major birth defects, miscarria…

Storage and supply

Atropine Sulfate Injection, USP 0.4 and 1 mg/mL are supplied in 1 mL, single-dose glass vials as follows: Table 2: How Supplied Concentration (mg/mL) Package Size NDC # 0.4 mg/mL 25 Vials 0517-1004-25 1 mg/mL 25 Vials 0517-1001-25 Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C and 30°C (59°F and 86°F).

Source: Atropine Sulfate (Atropine Sulfate) — US FDA prescribing information, 2023-11-10, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.