Comparative Pharmacology
Head-to-head clinical analysis: PROMETH PLAIN versus PROMETHAZINE DM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROMETH PLAIN versus PROMETHAZINE DM.
PROMETH PLAIN vs PROMETHAZINE DM
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 acts as a histamine H1 receptor antagonist, antiemetic via blockade of dopamine D2 receptors in the chemoreceptor trigger zone, and sedative via central anticholinergic effects. Dextromethorphan is an NMDA receptor antagonist and sigma-1 receptor agonist, suppressing cough by central action on the cough center.
12.5-25 mg intramuscularly or intravenously every 4-6 hours as needed; maximum 100 mg/day.
2 teaspoonfuls (10 mL) orally every 4-6 hours, not to exceed 8 teaspoonfuls (40 mL) per 24 hours.
None Documented
None Documented
Terminal elimination half-life is 10-14 hours in adults; may be prolonged in elderly or hepatic impairment.
16-19 hours (terminal); note: effect may last longer due to active metabolites and tissue binding
Primarily renal (approximately 70%) as metabolites and unchanged drug; biliary/fecal excretion accounts for ~20%.
Renal (70-80% as metabolites, <1% unchanged); biliary/fecal (20-30%)
Category C
Category A/B
Antihistamine
Antihistamine / Antiemetic