Comparative Pharmacology
Head-to-head clinical analysis: PROMETH PLAIN versus PROMETHAZINE WITH CODEINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROMETH PLAIN versus PROMETHAZINE WITH CODEINE.
PROMETH PLAIN vs PROMETHAZINE WITH CODEINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Antagonist at histamine H1 receptors; also exhibits anticholinergic, antiemetic, and sedative effects.
Promethazine is a phenothiazine derivative that antagonizes histamine at H1 receptors, acting as a sedative and antiemetic. Codeine is an opioid agonist at mu-opioid receptors, producing analgesia and antitussive effects via central nervous system depression.
12.5-25 mg intramuscularly or intravenously every 4-6 hours as needed; maximum 100 mg/day.
10-20 mg promethazine and 10-20 mg codeine (based on phosphate) orally every 4-6 hours as needed for cough; maximum daily codeine dose 120 mg.
None Documented
None Documented
Terminal elimination half-life is 10-14 hours in adults; may be prolonged in elderly or hepatic impairment.
Promethazine: 9-16 hours (mean 12 hours), clinically significant for sedation duration. Codeine: 2.5-4 hours (mean 3 hours), with active metabolite morphine 2-3 hours.
Primarily renal (approximately 70%) as metabolites and unchanged drug; biliary/fecal excretion accounts for ~20%.
Promethazine: renal 70% as metabolites and unchanged drug, biliary/fecal 20-30%. Codeine: renal 90% (5-15% unchanged, rest as morphine and conjugates), fecal <10%.
Category C
Category A/B
Antihistamine
Antihistamine / Antiemetic