Physostigmine is a parasympathomimetic, specifically, an irreversible cholinesterase inhibitor obtained from the Calabar bean. By interfering with the metabolism of acetylcholine, physostigmine indirectly stimulates both nicotinic and muscarinic receptors. CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences and alloys. ... The Anatomical Therapeutic Chemical Classification System is used for the classification of drugs. ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... The molecular mass of a substance (less accurately called molecular weight and abbreviated as MW) is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ... In pharmacology, bioavailability is used to describe the fraction of an administered dose of medication that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. ... The elimination half-life of a drug (or any xenobiotic agent) refers to the timecourse necessary for the quantity of the xenobiotic agent in the body (or plasma concentration) to be reduced to half of its original level through various elimination processes. ... Excretion is the biological process by which an organism chemically separates waste products from its body. ... The pregnancy category of a pharmaceutical agent is an assessment of the risk of fetal injury due to the pharmaceutical, if it is used as directed by the mother. ... The regulation of therapeutic goods, that is drugs and therapeutic devices, varies by jurisdiction. ... A parasympathomimetic is a drug or poison that acts by stimulating or mimicking the parasympathetic nervous system (PNS). ... A cholinesterase inhibitor or anticholinesterase is a chemical that inhibits a cholinesterase enzyme from breaking down acetylcholine, so increasing both the level and duration of action of the neurotransmitter acetylcholine. ... The Calabar bean is the seed of a leguminous plant, Physostigma venenosum, a native of tropical Africa. ... The chemical compound acetylcholine, often abbreviated as ACh, was the first neurotransmitter to be identified. ... Agonists An agonist is a substance that binds to a receptor and triggers a response in the cell. ... Nicotinic acetylcholine receptors, or nAChRs, are ionotropic receptors that form ion channels in cells plasma membranes. ... Muscarinic receptors are those membrane-bound acetylcholine receptors that are more sensitive to muscarine than to nicotine. ...

Clinical Uses

Physostigmine is used to treat glaucoma and delayed gastric emptying. Because it is a tertiary amine, it can cross the blood-brain barrier and so it is also used to treat the central nervous system effects of atropine and other anticholinergic drug overdoses. Possible adverse affects include depression. Overdose can cause a cholinergic syndrome. The blood-brain barrier is a physical barrier between the blood vessels in the central nervous system, and most parts of the central nervous system itself. ... A diagram showing the CNS: 1. ... Structure of atropine (hyoscyamine) Atropine is a tropane alkaloid extracted from the deadly nightshade (Atropa belladonna) and other plants of the family Solanaceae. ... An anticholinergic agent is a member of a class of pharmaceutical compounds which serve to reduce the effects mediated by acetylcholine in the central nervous system and peripheral nervous system. ...

Physostigmine is available in the U.S. under the trade names Antilirium, Eserine Salicylate, Isopto Eserine, and Eserine Sulfate.

See Also

Neostigmine Neostigmine is a parasympathomimetic, specifically, a reversible cholinesterase inhibitor. ...

Pyridostigmine Pyridostigmine is a parasympathomimetic and a reversible cholinesterase inhibitor. ...

Edrophonium Sources Brenner, G. M. (2000). ...

Sources

• Brenner, G. M. (2000). Pharmacology. Philadelphia, PA: W.B. Saunders Company. ISBN 0-7216-7757-6
• Canadian Pharmacists Association (2000). Compendium of Pharmaceuticals and Specialties (25th ed.). Toronto, ON: Webcom. ISBN 0-919115-76-4