Physostigmine

Physostigmine is a parasympathomimetic alkaloid, specifically, a reversible cholinesterase inhibitor. It occurs naturally in the Calabar bean and the ordeal tree of West Africa.

History

Physostigmine was first isolated in 1864 by Jobst and Hesse from the Calabar bean. It was used traditionally in West Africa as a poison, specifically in an ordeal where the accused was forced to ingest it.

Pharmacology

Physostigmine functions by inhibiting acetylcholinesterase, the enzyme that breaks down acetylcholine in the synaptic cleft of the neuromuscular junction. This causes an increase in the concentration of acetylcholine, leading to increased parasympathetic activity.

Medical uses

Physostigmine is used medically to treat glaucoma and to reverse the effects of non-depolarizing muscle relaxants. It is also used in the treatment of myasthenia gravis, Alzheimer's disease, and anticholinergic toxicity.

Side effects

Common side effects of physostigmine include nausea, vomiting, diarrhea, and abdominal pain. More serious side effects can include bradycardia, bronchospasm, and seizures.

See also

• Acetylcholine
• Cholinergic
• Parasympathomimetic drug
• Cholinesterase inhibitor

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  Chemical structure of Physostigmine
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  3D ball-and-stick model of Physostigmine
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  Julian synthesis of Physostigmine
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  Proposed biosynthesis pathway of Physostigmine