Comparative Pharmacology
Head-to-head clinical analysis: PROMETHAZINE DM versus VISTARIL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROMETHAZINE DM versus VISTARIL.
PROMETHAZINE DM vs VISTARIL
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, 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.
Hydroxyzine is a piperazine derivative antihistamine that acts as a competitive antagonist of histamine H1 receptors, thereby suppressing histamine activity in the subcortical area of the central nervous system. It also has anxiolytic, sedative, antiemetic, and antispasmodic effects.
2 teaspoonfuls (10 mL) orally every 4-6 hours, not to exceed 8 teaspoonfuls (40 mL) per 24 hours.
Oral: 50-100 mg 4 times daily; IM: 25-100 mg every 4-6 hours as needed.
None Documented
None Documented
16-19 hours (terminal); note: effect may last longer due to active metabolites and tissue binding
Terminal elimination half-life: 20-25 hours in adults; prolonged in hepatic impairment or elderly; steady-state achieved in ~4-5 days.
Renal (70-80% as metabolites, <1% unchanged); biliary/fecal (20-30%)
Primarily hepatic metabolism; <1% excreted unchanged in urine; biliary/fecal elimination of metabolites accounts for approximately 50-60% of total clearance.
Category A/B
Category C
Antihistamine / Antiemetic
Antihistamine