Comparative Pharmacology
Head-to-head clinical analysis: EMETE CON versus PROMETHAZINE HYDROCHLORIDE AND CODEINE PHOSPHATE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: EMETE CON versus PROMETHAZINE HYDROCHLORIDE AND CODEINE PHOSPHATE.
EMETE-CON vs PROMETHAZINE HYDROCHLORIDE AND CODEINE PHOSPHATE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Antiemetic; dopaminergic antagonist at D2 receptors in the chemoreceptor trigger zone; also exhibits anticholinergic and antihistaminic properties.
Promethazine is a phenothiazine derivative that antagonizes histamine H1 receptors, reducing allergic symptoms; it also has anticholinergic, antiemetic, and sedative effects. Codeine is an opioid agonist at mu-opioid receptors, producing analgesia and antitussive effects by central mechanisms.
12.5 mg intravenously over 30 seconds as a single dose; may repeat once after 1 hour if necessary.
Adults: 5 mL (containing promethazine 6.25 mg and codeine 10 mg) orally every 4-6 hours as needed; maximum 30 mL per day.
None Documented
None Documented
Terminal elimination half-life is 8-12 hours in adults with normal renal and hepatic function; may extend to 15-20 hours in elderly or patients with hepatic impairment.
Promethazine: 10-19 hours (range 5-30h); Codeine: 2.5-4 hours (rapidly metabolized); Clinical context: sustained antitussive effect from codeine despite short half-life. Half-life of promethazine extends with hepatic impairment.
Primarily hepatic metabolism (CYP2D6, CYP3A4) with <5% excreted unchanged in urine. Biliary/fecal excretion accounts for approximately 60-70% of metabolites, with renal elimination of metabolites constituting 25-35%.
Renal: Codeine and metabolites ~90% (free and conjugated), Promethazine and metabolites primarily renal; minor biliary/fecal (<5% for codeine, ~6% for promethazine).
Category C
Category A/B
Antiemetic
Antihistamine / Antiemetic