Comparative Pharmacology
Head-to-head clinical analysis: COMPAZINE versus PROMETHAZINE W CODEINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: COMPAZINE versus PROMETHAZINE W CODEINE.
COMPAZINE vs PROMETHAZINE W/ CODEINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Dopamine D2 receptor antagonist in the chemoreceptor trigger zone; also blocks alpha-1 adrenergic, histamine H1, and muscarinic M1 receptors.
Codeine is a prodrug converted to morphine, a mu-opioid receptor agonist, which inhibits nociceptive transmission; promethazine is a phenothiazine derivative with H1-receptor antagonism, anticholinergic, and antiemetic effects.
5-10 mg IM/IV every 3-4 hours as needed; or 25 mg PO/PR twice daily for severe nausea/vomiting.
10 mL (1 mg codeine, 6.25 mg promethazine per 5 mL) orally every 4-6 hours as needed for cough. Maximum: 60 mL per day. Do not exceed 5 days.
None Documented
None Documented
Terminal elimination half-life is approximately 23 hours (range 15-30 hours) after oral or intramuscular administration. Clinical context: requires multiple daily dosing for steady state.
Promethazine: 10-19 hours (terminal). Codeine: 2.5-3.5 hours (terminal); prolonged in renal impairment.
Renal (approximately 70% as metabolites, <1% unchanged), biliary/fecal (approximately 30%).
Promethazine: renal (70% as metabolites, <1% unchanged), fecal (20-30%). Codeine: renal (90%, of which 5-10% unchanged, rest as metabolites), fecal (minor).
Category C
Category A/B
Antipsychotic (Phenothiazine) / Antiemetic
Antihistamine / Antiemetic