Drug reference

Pirenzepine

Antimuscarinic

CDSCO approvedSchedule H

EXCRETION

—

not curated

INTERACTIONS

—

none in our sources

PREGNANCY

—

not curated

Mechanism

Pirenzepine is an M1 selective muscarinic receptor antagonist. It prevents acetylcholine from binding to M1 muscarinic receptors on effector cells at parasympathetic neuroeffector junctions, in peripheral ganglia, and in the CNS. Pirenzepine acts as an inverse agonist, shifting the equilibrium of constitutively active muscarinic receptors to an inactive state.

Indications

Peptic ulcer disease (used in Europe, Japan, and Canada, not in the U.S.)Healing of duodenal and gastric ulcersPrevention of ulcer recurrencePeptic ulcer (use declined)Peptic ulcer

Dosing

Adult: In the doses usually used, atropine has minimal stimulant effects on the CNS, especially the parasympathetic medullary centers, and a slower, longer lasting sedative effect on the brain. Scopolamine has more marked central effects, producing drowsiness when given in recommended dosages and amnesia in sensitive individuals that may be mediated via the histamine H3 receptor.…

Contraindications

Rarely used today due to poor efficacy and significant side effects

Side effects

Common

Lower incidence of xerostomiaLower incidence of blurred visionLower incidence of central muscarinic disturbancesSignificant and undesirable anticholinergic side effects

Serious