Comparative Pharmacology
Head-to-head clinical analysis: PROCHLORPERAZINE versus PROMETHAZINE W DEXTROMETHORPHAN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROCHLORPERAZINE versus PROMETHAZINE W DEXTROMETHORPHAN.
PROCHLORPERAZINE vs PROMETHAZINE W/ DEXTROMETHORPHAN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Prochlorperazine is a phenothiazine antipsychotic that acts as a dopamine D2 receptor antagonist in the chemoreceptor trigger zone (CTZ) and at high doses in the mesolimbic system. It also has anticholinergic and antiemetic effects.
Promethazine is a phenothiazine derivative that acts as a histamine H1 receptor antagonist and antiemetic; dextromethorphan is a non-opioid antitussive that acts as an NMDA receptor antagonist and sigma-1 receptor agonist.
5-10 mg IM/IV every 3-4 hours as needed; or 5-10 mg PO 3-4 times daily; or 25 mg PR twice daily. Maximum IM/IV: 40 mg/day; PO: 40 mg/day.
5 mL (containing promethazine 6.25 mg and dextromethorphan 15 mg) orally every 4-6 hours as needed, not to exceed 30 mL (promethazine 37.5 mg, dextromethorphan 90 mg) per 24 hours.
None Documented
None Documented
Clinical Note
moderateProchlorperazine + Fluticasone propionate
"The risk or severity of adverse effects can be increased when Prochlorperazine is combined with Fluticasone propionate."
Clinical Note
moderateProchlorperazine + Haloperidol
"The metabolism of Haloperidol can be decreased when combined with Prochlorperazine."
Clinical Note
moderateProchlorperazine + Methylphenidate
"The risk or severity of adverse effects can be increased when Prochlorperazine is combined with Methylphenidate."
Clinical Note
moderateTerminal elimination half-life: 23-25 hours, with prolonged elimination in hepatic impairment.
Promethazine: 9-16 h; dextromethorphan: 3-5 h (extensive metabolizers), 30-50 h (poor metabolizers). Clinical context: dosing interval typically 4-6 h for dextromethorphan; promethazine accumulates with repeated dosing.
Renal: 70-80% (as metabolites), Fecal: 20-30% (unchanged and metabolites), Biliary: 10-15% of dose excreted in bile.
Renal: promethazine ~6% unchanged, dextromethorphan ~0.5% unchanged; metabolites primarily renal. Biliary/fecal: minor routes for both.
Category A/B
Category A/B
Typical Antipsychotic / Antiemetic
Antihistamine / Antiemetic
Prochlorperazine + Quinagolide
"The therapeutic efficacy of Quinagolide can be decreased when used in combination with Prochlorperazine."