Comparative Pharmacology
Head-to-head clinical analysis: PROMETHAZINE HYDROCHLORIDE PHENYLEPHRINE HYDROCHLORIDE W CODEINE PHOSPHATE versus VONTROL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROMETHAZINE HYDROCHLORIDE PHENYLEPHRINE HYDROCHLORIDE W CODEINE PHOSPHATE versus VONTROL.
PROMETHAZINE HYDROCHLORIDE,PHENYLEPHRINE HYDROCHLORIDE W/CODEINE PHOSPHATE vs VONTROL
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.
VONTROL (trimethobenzamide) acts centrally to inhibit the chemoreceptor trigger zone (CTZ) in the medulla oblongata, thereby suppressing nausea and vomiting. Its exact mechanism is not fully understood but may involve antagonism of dopamine D2 receptors and serotonin 5-HT3 receptors.
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.
10 mg orally twice daily; maximum 20 mg/day.
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 hours; prolonged in renal impairment (up to 24 hours in ESRD)
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: 60% unchanged; fecal: 30% (biliary); hepatic metabolism: 10%
Category A/B
Category C
Antihistamine / Antiemetic
Antiemetic