|Dextromethorphan||Sigma-1 receptor agonist, NMDA receptor antagonist|
|Other names||AVP-786, AVP-923|
|Bioavailability||dextromethorphan 11%, quinidine 70-80%. Food has no effect on absorption.|
|Metabolism||Liver, extensive. Dextromethorphan is catalyzed by CYP2D6. Quinidine is metabolized by CYP3A4 and competitively inhibits the metabolism of dextromethorphan to increase and prolong plasma concentrations of dextromethorphan|
|Elimination half-life||dextromethorphan 13h, quinidine 7h|
Dextromethorphan/quinidine was approved for medical use in the United States in October 2010, and is marketed by Avanir Pharmaceuticals.
- Atrioventricular (AV) block, complete, without implanted pacemaker or at high risk of complete AV block
- Concomitant use with drugs containing quinidine, quinine, or mefloquine
- Concomitant use with drugs that both prolong the QT interval and are metabolized by CYP2D6 (e.g., thioridazine, pimozide); effects on QT interval may be increased
- Concomitant use with MAOIs or use of MAOIs within 14 days; risk of serious, potentially fatal, drug interactions including serotonin syndrome
- Heart failure
- Hypersensitivity to dextromethorphan
- Hypersensitivity to quinine, mefloquine, quinidine, or dextromethorphan/quinidine with a history of thrombocytopenia, hepatitis, bone marrow depression or lupus-like syndrome induced by these drugs
- QT interval, prolonged or congenital long QT syndrome or a history suggesting torsades de pointes
Common risks and side effects include:
- Abdominal pain
- Diarrhea (reported in 13% of patients)
- Elevated gamma glutamyltransferase
- Prolonged QT interval
- Muscle spasm
- Peripheral edema
- Urinary tract infection
- Desipramine (CYP2D6 substrate) levels increase 8-fold with co-administration
- Paroxetine (CYP2D6 inhibitor and substrate)
In June 2012, drug discovery and development magazine reported that Avanir Pharmaceuticals plans to test the drug for the treatment of agitation associated with Alzheimer's disease. The drug is also under investigation for the treatment of major depressive disorder. As of May 2021, the drug is also in clinical trial for negative symptoms of schizophrenia.
- "Dextromethorphan / quinidine (Nuedexta) Use During Pregnancy". Drugs.com. 21 August 2019. Retrieved 13 September 2020.
- "Nuedexta- dextromethorphan hydrobromide and quinidine sulfate capsule, gelatin coated". DailyMed. 23 June 2019. Retrieved 23 October 2020.
- "Drug Approval Package: Nuedexta (dextromethorphan hydrobromide and quinidine sulfate) Capsules NDA #021879". U.S. Food and Drug Administration (FDA). 24 December 1999. Retrieved 23 October 2020. Lay summary (PDF).
- "NNuedexta Testing New Indication". CDrug Discovery and Development Magazine. June 13, 2011.
- Nguyen, Linda; Thomas, Kelan L.; Lucke-Wold, Brandon P.; Cavendish, John Z.; Crowe, Molly S.; Matsumoto, Rae R. (2016). "Dextromethorphan: An update on its utility for neurological and neuropsychiatric disorders". Pharmacology & Therapeutics. 159: 1–22. doi:10.1016/j.pharmthera.2016.01.016. ISSN 0163-7258. PMID 26826604.
- Avanir Pharmaceuticals (2021-04-26). "A Multicenter, Randomized, Double-blind, Placebo-controlled, Parallel-arm Study to Assess the Efficacy, Safety, and Tolerability of AVP-786 (Deudextromethorphan Hydrobromide [d6-DM]/Quinidine Sulfate [Q]) for the Treatment of Negative Symptoms of Schizophrenia". Cite journal requires
- "Dextromethorphan hydrobromide mixture with quinidine sulfate". Drug Information Portal. U.S. National Library of Medicine.