Atropine

Atropine is an alkaloid originally synthesized from Atropa belladonna. It is a racemic mixture of d-and l-hyoscyamine, of which only l-hyoscyamine is pharmacologically active. Atropine is generally available as a sulfate salt and can be administered by intravenous, subcutaneous, intramuscular, intraosseous, endotracheal and ophthalmic methods. Oral atropine is only available in combination products. Atropine is a competitive, reversible antagonist of muscarinic receptors that blocks the effects of acetylcholine and other choline esters. It has a variety of therapeutic applications, including pupil dilation and the treatment of anticholinergic poisoning and symptomatic bradycardia in the absence of reversible causes. Atropine is a relatively inexpensive drug and is included in the World Health Organization List of Essential Medicines.

The intravenous, intramuscular, subcutaneous, intraosseous and endotracheal use of atropine is indicated for the temporary blockade of severe or life-threatening muscarinic effects. The intramuscular use of atropine in the form of a pen injector is indicated for the treatment of poisoning by susceptible organophosphorus nerve agents having cholinesterase activity as well as organophosphorus or carbamate insecticides in adult and pediatric patients. The ophthalmic use of atropine is indicated for mydriasis, cycloplegia, and penalization of the healthy eye in the treatment of amblyopia.

In combination with difenoxin or diphenoxylate (tablets for oral use), atropine is indicated as adjunctive therapy in the management of acute nonspecific diarrhea.