What is the dose of Nuedexta (dextromethorphan and quinidine)?

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Last updated: March 27, 2025View editorial policy

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From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Nuedexta is typically prescribed at a dose of 20 mg of dextromethorphan and 10 mg of quinidine, taken as one capsule every 12 hours, after an initial starting dose of one capsule daily for the first week. This medication is FDA-approved specifically for treating pseudobulbar affect (PBA), a condition characterized by uncontrollable laughing or crying episodes that don't match how a person feels. The dextromethorphan works on brain receptors to reduce emotional expression, while the quinidine prevents the rapid breakdown of dextromethorphan, allowing it to reach effective levels in the brain, as shown in studies such as 1 and 2.

Key Points to Consider

  • The recommended dosages of Nuedexta are 20/10 mg twice daily, as indicated in 1 and 3.
  • Patients should take Nuedexta exactly as prescribed, with or without food, and should not adjust the dose without consulting their healthcare provider.
  • Common side effects include dizziness, diarrhea, cough, and weakness, as noted in 1 and 2.
  • Patients with heart rhythm disorders, those taking certain antidepressants (particularly MAOIs), or those with quinidine, quinine, or mefloquine allergies should not take this medication due to potential serious interactions and side effects, as warned in 3 and 2.

Clinical Evidence

The clinical evidence supporting the use of Nuedexta for PBA is based on several large-scale trials, including the STAR trial, which demonstrated the efficacy and safety of dextromethorphan/quinidine 20/10 mg twice daily in patients with PBA and ALS or MS, as reported in 1 and 3. Additionally, a 12-week open-label extension phase showed further improvements in the severity of the condition, as noted in 1.

Safety and Tolerability

The safety and tolerability of Nuedexta have been evaluated in several studies, including the STAR trial, which found that the drug was generally well tolerated, with no particular safety or tolerability concerns, as indicated in 1 and 2. However, patients should be monitored for potential side effects, such as dizziness, diarrhea, cough, and weakness, and should not take the medication if they have certain medical conditions or are taking certain medications, as warned in 3 and 2.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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