Deudextromethorphan/quinidine

Deudextromethorphan/quinidine is a combination medication used in the treatment of Pseudobulbar Affect (PBA). This condition is characterized by uncontrollable, inappropriate laughing or crying, often seen in people with certain neurological conditions or injuries. The medication combines two active ingredients: deudextromethorphan and quinidine.

Composition

The medication is composed of two active ingredients: Deudextromethorphan and Quinidine. Deudextromethorphan is a NMDA receptor antagonist and sigma-1 receptor agonist, and it is the active ingredient responsible for the therapeutic effect of the medication. Quinidine, on the other hand, is a class I antiarrhythmic agent that serves to increase the bioavailability of deudextromethorphan through inhibition of the CYP2D6 enzyme.

Mechanism of Action

The exact mechanism of action of deudextromethorphan/quinidine in the treatment of PBA is not fully understood. However, it is believed that deudextromethorphan's antagonism of NMDA receptors and agonism of sigma-1 receptors in the brain play a key role. Quinidine increases the concentration of deudextromethorphan by inhibiting its metabolism by the CYP2D6 enzyme.

Indications

Deudextromethorphan/quinidine is indicated for the treatment of PBA. It is not intended for other types of emotional lability that can occur in individuals with neurological conditions or injuries.

Side Effects

Common side effects of deudextromethorphan/quinidine include dizziness, diarrhea, cough, vomiting, asthenia, peripheral edema, urinary tract infections, influenza, increased gamma-glutamyltransferase, and flatulence. Serious side effects may include thrombocytopenia and hepatitis.

Contraindications

Deudextromethorphan/quinidine is contraindicated in individuals with a history of quinidine, quinine, or mefloquine-induced thrombocytopenia, hepatitis, bone marrow depression, or lupus-like syndrome. It is also contraindicated in individuals who are hypersensitive to dextromethorphan.

Interactions

Deudextromethorphan/quinidine can interact with a number of other medications, including monoamine oxidase inhibitors (MAOIs), quinidine, quinine, mefloquine, SSRIs, and tricyclic antidepressants.

See Also

• Pseudobulbar Affect
• NMDA receptor antagonist
• Sigma-1 receptor
• CYP2D6