Dextromethorphan Hydrobromide and Quinidine Sulfate

Dextromethorphan hydrobromide and quinidine sulfate capsules are indicated for the treatment of pseudobulbar affect (PBA). PBA occurs secondary to a variety of otherwise unrelated neurologic conditions, and is characterized by involuntary, sudden, and frequent episodes of laughing and/or crying. PBA episodes typically occur out of proportion or incongruent to the underlying emotional state. PBA is a specific condition, distinct from other types of emotional lability that may occur in patients with neurological disease or injury.

12.1 Mechanism of Action Dextromethorphan (DM) is a sigma-1 receptor agonist and an uncompetitive NMDA receptor antagonist. Quinidine increases plasma levels of dextromethorphan by competitively inhibiting cytochrome P450 2D6, which catalyzes a major biotransformation pathway for dextromethorphan. The mechanism by which dextromethorphan exerts therapeutic effects in patients with pseudobulbar affect is unknown.

With Localized tissue retention for Dextromethorphan Hydrobromide and Quinidine Sulfate with minimal systemic plasma half-life residence kinetics and < 5% transdermal or mucosal systemic uptake from Dextromethorphan Hydrobromide and Quinidine Sulfate bioavailability, Dextromethorphan Hydrobromide and Quinidine Sulfate undergoes hepatic oxidation via cyp2d6 followed by renal and biliary excretion of dextromethorphan hydrobromide and quinidine sulfate metabolites and establishes therapeutic activity over initial local symptom modulation in 30–90 minutes; full tissue response over 1–3 weeks (dextromethorphan hydrobromide and quinidine sulfate).

Standard adult regimens span 20 mg/1 / 10 mg/1 Capsule, Gelatin Coated, 20 mg/1 / 10 mg/1 Capsule. Prescribers screen specifically against concomitant use with quinidine, quinine, or mefloquine.; ( 4.1 ) patients with a history of quinidine, quinine or mefloquine-induced thrombocytopenia, hepatitis, or other hypersensitivity reactions.; ( 4.2 ) patients with known hypersensitivity to dextromethorphan., while community micro-logs most frequently note nausea (8.8% of reports), headache (8.3% of reports), dizziness (6.8% of reports).