Comparative Pharmacology
Head-to-head clinical analysis: DEXTROMETHORPHAN HYDROBROMIDE AND QUINIDINE SULFATE versus QUALAQUIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DEXTROMETHORPHAN HYDROBROMIDE AND QUINIDINE SULFATE versus QUALAQUIN.
DEXTROMETHORPHAN HYDROBROMIDE AND QUINIDINE SULFATE vs QUALAQUIN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Dextromethorphan is an uncompetitive NMDA receptor antagonist and sigma-1 receptor agonist; quinidine is a CYP2D6 inhibitor that increases dextromethorphan bioavailability.
Quinine is a cinchona alkaloid that acts as a blood schizonticide against Plasmodium species. It inhibits heme polymerase in the parasite, leading to accumulation of toxic heme and parasite death. It also has weak gametocytocidal activity against P. vivax and P. malariae.
One capsule (dextromethorphan 20 mg/quinidine 10 mg) orally once daily, with a maximum dose of two capsules per day.
325-650 mg orally every 6 hours as needed for pain; maximum 2.6 g/day.
None Documented
None Documented
Dextromethorphan: 2-4 hours (extensive metabolizers); quinidine: 6-8 hours (inhibits CYP2D6, prolonging dextromethorphan half-life in poor metabolizers to >20 hours)
Terminal elimination half-life approximately 8 hours in healthy adults; prolonged in hepatic impairment (up to 12-18 hours) and severe malaria (up to 14-20 hours).
Renal: quinidine 15-25% unchanged, dextromethorphan <1% unchanged; biliary/fecal: quinidine metabolites ~5%, dextromethorphan metabolites ~60-80% as dextrorphan conjugates
Renal (approximately 20% unchanged; remainder as metabolites); biliary/fecal (minor).
Category A/B
Category C
Antiarrhythmic (Class Ia)
Antiarrhythmic (Class Ia)