indication

Propiomazine is largely used for its antihistamininc sleep inducing effects in treating insomnia.

pharmacology

Although propiomazine is a phenothiazine, it is not used as an antipsychotic. It posesses antihistamine effects and is mostly used as a sedative in treating insomnia.

mechanism of action

Propiomazine is an antagonist at types 1, 2, and 4 dopamine receptors, serotonin (5-HT) receptor types 2A and 2C, muscarinic receptors 1 through 5, alpha(1)-receptors, and histamine H1-receptors. Its main use as a sedative is due to its antihistamine effect.

toxicity

Rare, serious side effects include convulsions (seizures); difficult or unusually fast breathing; fast or irregular heartbeat or pulse; fever (high); high or low blood pressure; loss of bladder control; muscle stiffness (severe); unusual increase in sweating; unusually pale skin; and unusual tiredness or weakness.

biotransformation

Unknown, but most likely hepatic as with other phenothiazines.

drug interactions

Bromocriptine: The phenothiazine decreases the effect of bromocriptine

Cisapride: Increased risk of cardiotoxicity and arrhythmias

Dexfenfluramine: Decreased anorexic effect, may increase psychotic symptoms

Diethylpropion: Decreased anorexic effect, may increase psychotic symptoms

Fenfluramine: Decreased anorexic effect, may increase psychotic symptoms

Gatifloxacin: Increased risk of cardiotoxicity and arrhythmias

Grepafloxacin: Increased risk of cardiotoxicity and arrhythmias

Guanethidine: Propiomazine may decrease the effect of guanethidine.

Levofloxacin: Increased risk of cardiotoxicity and arrhythmias

Mazindol: Decreased anorexic effect, may increase psychotic symptoms

Phentermine: Decreased anorexic effect, may increase psychotic symptoms

Phenylpropanolamine: Decreased anorexic effect, may increase psychotic symptoms

Terfenadine: Increased risk of cardiotoxicity and arrhythmias