Comparative Pharmacology
Head-to-head clinical analysis: DEXTROMETHORPHAN POLISTIREX versus PHERAZINE DM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DEXTROMETHORPHAN POLISTIREX versus PHERAZINE DM.
DEXTROMETHORPHAN POLISTIREX vs PHERAZINE DM
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Dextromethorphan polistirex is an NMDA receptor antagonist and sigma-1 receptor agonist. It inhibits serotonin reuptake and acts on the brain stem cough center to elevate the threshold for coughing.
Phererazine DM is a combination of promethazine (a phenothiazine derivative with antihistaminic, sedative, antiemetic, and anticholinergic properties) and dextromethorphan (a non-opioid antitussive that acts on the sigma-1 receptor and NMDA receptor antagonist). Promethazine blocks H1 receptors and reduces histamine-mediated symptoms, while dextromethorphan suppresses cough by central action on the cough center.
30-60 mg orally every 12 hours; not to exceed 120 mg in 24 hours.
Adults: 1 tablet (promethazine 25 mg / dextromethorphan 30 mg) orally every 6-8 hours as needed; maximum 4 tablets per day.
None Documented
None Documented
Terminal half-life: 13–19 hours; clinical context: extended-release formulation due to polistirex complex; time to steady-state: ~3 days
Terminal elimination half-life: 3-4 hours in children; 5-6 hours in adults; up to 8 hours in elderly. Clinical context: Dosing interval adjustment needed in renal impairment.
Renal: ~45% as unchanged drug and metabolites (dextrorphan conjugates); fecal: <2%; biliary: minimal
Primarily renal: 60-70% as unchanged drug and glucuronide conjugate; 15-20% fecal via biliary excretion.
Category C
Category C
Antitussive
Antitussive/Antihistamine Combination