indication

For use as adjunctive therapy in the treatment of peptic ulcer. It has not been shown to be effective in contributing to the healing of peptic ulcer, decreasing the rate of recurrence, or preventing complications.

pharmacology

Mepenzolate diminishes gastric acid and pepsin secretion. Mepenzolate also suppresses spontaneous contractions of the colon. Pharmacologically, it is a post-ganglionic parasympathetic inhibitor.

mechanism of action

Mepenzolate is a post-ganglionic parasympathetic inhibitor. It specifically antagonizes muscarinic receptors. This leads to decreases in gastric acid and pepsin secretion and suppression of spontaneous contractions of the colon.

toxicity

The signs and symptoms of overdosage are headache; nausea; vomiting; blurred vision; dilated pupils; hot, dry skin; dizziness; dryness of the mouth; difficulty in swallowing; and CNS stimulation. A curare-like action may occur (i.e., neuromuscular blockade leading to muscular weakness and possible paralysis). The oral LD₅₀ is greater than 750 mg/kg in mice and greater than 1000 mg/kg in rats.

absorption

Between 3 and 22% of an orally administered dose is excreted in the urine over a 5-day period, with the majority of the radioactivity appearing on Day 1. The remainder appears in the next 5 days in the feces and presumably has not been absorbed.

route of elimination

Between 3 and 22% of an orally administered dose is excreted in the urine over a 5-day period, with the majority of the radioactivity appearing on Day 1.

drug interactions

Haloperidol: The anticholinergic increases the risk of psychosis and tardive dyskinesia

Tacrine: The therapeutic effects of the central acetylcholinesterase inhibitor, Tacrine, and/or the anticholinergic, Mepenzolate, 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 Mepenzolate, two anticholinergics, may cause additive anticholinergic effects and enhance their adverse/toxic effects. Monitor for enhanced anticholinergic effects.

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

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