Comparative Pharmacology
Head-to-head clinical analysis: DISOPHROL versus PROMETHAZINE HYDROCHLORIDE AND DEXTROMETHORPHAN HYDROBROMIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DISOPHROL versus PROMETHAZINE HYDROCHLORIDE AND DEXTROMETHORPHAN HYDROBROMIDE.
DISOPHROL vs PROMETHAZINE HYDROCHLORIDE AND DEXTROMETHORPHAN HYDROBROMIDE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Disophrol is a combination of dexbrompheniramine, a first-generation antihistamine that blocks H1 receptors, and pseudoephedrine, a sympathomimetic amine that stimulates alpha-adrenergic receptors causing vasoconstriction.
Promethazine is a phenothiazine derivative that acts as a histamine H1 receptor antagonist, antiemetic, and sedative. Dextromethorphan is a cough suppressant that acts as an NMDA receptor antagonist and sigma-1 receptor agonist.
1 tablet (6 mg dexbrompheniramine maleate / 60 mg pseudoephedrine sulfate) orally every 4-6 hours; not to exceed 4 tablets in 24 hours.
For cough and upper respiratory symptoms: 5 mL (containing promethazine hydrochloride 6.25 mg and dextromethorphan hydrobromide 15 mg) orally every 4 to 6 hours, not to exceed 30 mL in 24 hours.
None Documented
None Documented
Terminal elimination half-life is 3-4 hours in adults; in renal impairment, half-life may be prolonged up to 8-12 hours requiring dose adjustment.
Promethazine: 10-19 hours (mean 12 hours). Dextromethorphan: extensive metabolizers (CYP2D6) 3-5 hours; poor metabolizers 20-30 hours. Clinical context: accumulation with repeated dosing, especially in poor metabolizers.
Renal excretion of unchanged drug and metabolites; approximately 60-70% of a dose eliminated in urine as unchanged drug and glucuronide conjugates, with <10% in feces.
Promethazine: primarily hepatic metabolism, renal excretion of metabolites (~70%, <1% unchanged); fecal excretion (20-30%). Dextromethorphan: hepatic metabolism, renal excretion of metabolites and <1% unchanged drug.
Category C
Category A/B
Antihistamine/Decongestant Combination
Antihistamine / Antiemetic