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Combination of
DextromethorphanSigma-1 receptor agonist, NMDA receptor antagonist
QuinidineAntiarrhythmic agent (CYP2D6 inhibitor)
Trade namesNuedexta
Other namesAVP-786, AVP-923
Clinical data
Main usesPseudobulbar affect (PBA)[1]
Side effectsDiarrhea, dizziness, cough, vomiting, peripheral swelling, urinary tract infection[1]
  • US: C (Risk not ruled out)[2]
Routes of
By mouth
External links
License data
Legal status
  • US: ℞-only
  • In general: ℞ (Prescription only)
BioavailabilityDextromethorphan 11%, quinidine 70-80%. Food has no effect on absorption.
MetabolismLiver, 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-lifeDextromethorphan 13h, quinidine 7h
ExcretionQuinidine 5-20%

Dextromethorphan/quinidine, sold under the brand name Nuedexta, is a combination medication used to treat pseudobulbar affect (PBA).[1] This includes PBA that may occur in amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and dementia.[3] It is taken by mouth.[1]

Common side effects include diarrhea, dizziness, cough, vomiting, peripheral swelling, and urinary tract infection.[1] Other side effects may include low platelets, QT prolongation, liver problems, and serotonin syndrome.[1] It contains dextromethorphan, a NMDA receptor antagonist and quinidine, a CYP2D6 inhibitor.[1] Quinidine is used to increase the activity of dextromethorphan.[3]

The combination was approved for medical use in the United States in 2010.[1] While it was approved in Europe in 2013; this approval was subsequently withdrawn.[4] In the United States 60 tablets costs about 1,300 USD as of 2021.[5]

Medical uses


It is started at a dose of one pill per day, and than after a week increased to one pill twice per day.[1]


  • 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

Side effects

Common risks and side effects include:[1]



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.[6] The drug is also under investigation for the treatment of major depressive disorder.[1] Archived 2019-03-29 at the Wayback Machine[7] As of May 2021, the drug is also in clinical trial for negative symptoms of schizophrenia.[8]

See also


  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 "Nuedexta- dextromethorphan hydrobromide and quinidine sulfate capsule, gelatin coated". DailyMed. 23 June 2019. Archived from the original on 20 October 2020. Retrieved 23 October 2020.
  2. "Dextromethorphan / quinidine (Nuedexta) Use During Pregnancy". 21 August 2019. Archived from the original on 20 January 2021. Retrieved 13 September 2020.
  3. 3.0 3.1 "Dextromethorphan and quiNIDine Monograph for Professionals". Archived from the original on 28 January 2021. Retrieved 23 December 2021.
  4. "Nuedexta". Archived from the original on 28 August 2021. Retrieved 23 December 2021.
  5. "Nuedexta Prices, Coupons & Savings Tips - GoodRx". GoodRx. Archived from the original on 17 May 2020. Retrieved 23 December 2021.
  6. "NNuedexta Testing New Indication". CDrug Discovery and Development Magazine. June 13, 2011. Archived from the original on April 9, 2016. Retrieved May 10, 2021.
  7. 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.
  8. 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". Archived from the original on 2021-05-10. Retrieved 2021-05-10. {{cite journal}}: Cite journal requires |journal= (help)

External links