Comparative Pharmacology
Head-to-head clinical analysis: PROMETHAZINE W DEXTROMETHORPHAN versus TORECAN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROMETHAZINE W DEXTROMETHORPHAN versus TORECAN.
PROMETHAZINE W/ DEXTROMETHORPHAN vs TORECAN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
TORECAN (thiethylperazine) is a phenothiazine derivative that acts primarily as a dopamine D2 receptor antagonist in the chemoreceptor trigger zone (CTZ) to exert antiemetic effects. It also possesses anticholinergic and antihistaminergic properties.
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.
10 mg orally or intramuscularly every 6 to 8 hours as needed for nausea and vomiting.
None Documented
None Documented
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.
Terminal elimination half-life: 6-8 hours. Clinical context: Allows twice-daily dosing; prolonged in renal impairment.
Renal: promethazine ~6% unchanged, dextromethorphan ~0.5% unchanged; metabolites primarily renal. Biliary/fecal: minor routes for both.
Primarily renal (60-70% as unchanged drug and metabolites); biliary/fecal (20-30%).
Category A/B
Category C
Antihistamine / Antiemetic
Antiemetic