Comparative Pharmacology
Head-to-head clinical analysis: COMPAZINE versus PROMETHAZINE HYDROCHLORIDE CODEINE PHOSPHATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: COMPAZINE versus PROMETHAZINE HYDROCHLORIDE CODEINE PHOSPHATE.
COMPAZINE vs PROMETHAZINE HYDROCHLORIDE; CODEINE PHOSPHATE
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.
Promethazine is a phenothiazine derivative that acts as a histamine H1 receptor antagonist, antiemetic, and sedative via blockade of central and peripheral H1 receptors and antagonism of dopamine D2 receptors. Codeine is an opioid agonist that binds to mu-opioid receptors in the CNS, producing analgesia and cough suppression; it also has antitussive effects via central action.
5-10 mg IM/IV every 3-4 hours as needed; or 25 mg PO/PR twice daily for severe nausea/vomiting.
Promethazine hydrochloride 6.25-25 mg / codeine phosphate 10-20 mg (based on codeine component) orally every 4-6 hours as needed. Maximum codeine dose: 60 mg per dose, 120 mg per day.
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: 2.4-4 hours (terminal), prolonged in hepatic impairment. Clinical context: Dosing interval typically 4-6 hours for codeine; promethazine accumulates with repeated dosing.
Renal (approximately 70% as metabolites, <1% unchanged), biliary/fecal (approximately 30%).
Promethazine: Renal (70-80% as metabolites, <1% unchanged); Codeine: Renal (70-90% as metabolites, 5-15% unchanged). Biliary/feces: Minor (<10% total).
Category C
Category A/B
Antipsychotic (Phenothiazine) / Antiemetic
Antihistamine / Antiemetic