indication

Used as adjunctive therapy for the treatment of peptic ulcer. Also used to treat nausea and vomiting due to motion sickness.

pharmacology

Methscopolamine is a muscarinic antagonist structurally similar to the neurotransmitter acetylcholine and acts by blocking the muscarinic acetylcholine receptors and is thus classified as an anticholinergic. Methscopolamine has many uses including the prevention of motion sickness. It is not clear how Methscopolamine prevents nausea and vomiting due to motion sickness. The vestibular part of the ear is very important for balance. When a person becomes disoriented due to motion, the vestibule sends a signal through nerves to the vomiting center in the brain, and vomiting occurs. Acetylcholine is a chemical that nerves use to transmit messages to each other. It is believe that Methscopolamine prevents communication between the nerves of the vestibule and the vomiting center in the brain by blocking the action of acetylcholine. Methscopolamine also may work directly on the vomiting center. Methscopolamine must be taken before the onset of motion sickness to be effective.

mechanism of action

Methscopolamine acts by interfering with the transmission of nerve impulses by acetylcholine in the parasympathetic nervous system (specifically the vomiting center). It does so by acting as a muscarinic antagonist.

toxicity

Symptoms of a methscopolamine overdose include headache, nausea, vomiting, dry mouth, difficulty swallowing, blurred vision, dilated pupils, hot, dry skin, dizziness; drowsiness, confusion, anxiety, seizures, weak pulse, and an irregular heartbeat. In addition, a curare-like action may occur, i.e., neuromuscular blockade leading to muscular weakness and possible paralysis.

biotransformation

Little is known about the fate and excretion of methscopolamine.

absorption

Poorly and unreliably absorbed, total absorption is 10-25%.

drug interactions

Cinitapride: Anticholinergic agents like methylscopolamine may reduce the action of cinitapride.

Donepezil: Possible antagonism of action

Galantamine: Possible antagonism of action

Tacrine: The therapeutic effects of the central acetylcholinesterase inhibitor, Tacrine, and/or the anticholinergic, Methylscopolamine, may be reduced due to antagonism. The interaction may be beneficial when the anticholinergic action is a side effect. Monitor for decreased efficacy of both agents.

Trimethobenzamide: Trimethobenzamide and Methylscopolamine, two anticholinergics, may cause additive anticholinergic effects and enhance their adverse/toxic effects. Monitor for enhanced anticholinergic effects.

Triprolidine: Triprolidine and Methylscopolamine, two anticholinergics, may cause additive anticholinergic effects and enhance their adverse/toxic effects. Monitor for enhanced anticholinergic effects.

Trospium: Trospium and Methylscopolamine, two anticholinergics, may cause additive anticholinergic effects and enhanced adverse/toxic effects. Monitor for enhanced anticholinergic effects.