Comparative Pharmacology
Head-to-head clinical analysis: PROMETHAZINE HYDROCHLORIDE PHENYLEPHRINE HYDROCHLORIDE W CODEINE PHOSPHATE versus TIGAN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROMETHAZINE HYDROCHLORIDE PHENYLEPHRINE HYDROCHLORIDE W CODEINE PHOSPHATE versus TIGAN.
PROMETHAZINE HYDROCHLORIDE,PHENYLEPHRINE HYDROCHLORIDE W/CODEINE PHOSPHATE vs TIGAN
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, sedative, and antiemetic via central dopamine D2 and muscarinic M1 receptor blockade. Phenylephrine is a sympathomimetic amine that acts as a selective α1-adrenergic receptor agonist, causing vasoconstriction. Codeine is an opioid agonist at mu-opioid receptors, producing analgesia and antitussive effects, partly after O-demethylation to morphine.
TIGAN (trimethobenzamide) acts on the chemoreceptor trigger zone (CTZ) to inhibit emetic stimuli, primarily through antagonism of dopamine D2 receptors, though its exact mechanism is not fully elucidated.
Each 5 mL of oral solution contains promethazine hydrochloride 6.25 mg, phenylephrine hydrochloride 5 mg, and codeine phosphate 10 mg. Adult dose: 5 mL every 4 to 6 hours as needed. Maximum 30 mL per day.
Adults: 200 mg IM or 100 mg PO or 200 mg PR every 6–8 hours as needed.
None Documented
None Documented
Promethazine: 9-16 h (adults); prolonged in hepatic impairment. Phenylephrine: 2-3 h (oral); 5-10 min (IV due to rapid redistribution). Codeine: 2.5-3.5 h; active metabolites (morphine) 2-3 h.
12-15 hours; may be prolonged in hepatic impairment.
Promethazine: ~70% renal as metabolites, minor biliary/fecal. Phenylephrine: ~86-96% renal as metabolites (sulfate and glucuronide conjugates). Codeine: ~90% renal, primarily as morphine and norcodeine conjugates; 5-10% unchanged. Fecal excretion minimal.
Renal (30-50% as unchanged drug and metabolites), biliary/fecal (minor).
Category A/B
Category C
Antihistamine / Antiemetic
Antiemetic