Dextromethorphan hydrobromide and Quinidine sulfate (Nuedexta®)


Indications for Prior Authorization:

  • Treatment of Pseudobulbar Affect (PBA) secondary to ALS (amyotrophic lateral sclerosis) or MS (multiple sclerosis) patients

Patients must meet the following criteria for the indication(s) above:

  • Diagnosis of PBA secondary to MS or ALS as supported by chart note documentation, AND
  • Prescribed by or in consultation with a neurologist, AND
  • Baseline Center for Neurologic Study-Lability Scale (CNS-LS) score >13, AND
  • Dose does not exceed 40mg dextromethorphan and 20mg quinidine per day (2 capsules per day), AND
  • Does not have a contraindication to therapy:
    • Concomitant use with quinidine, quinine, or mefloquine
    • Patients with a history of quinidine, quinine, or mefloquine-induced thrombocytopenia, hepatitis, or other hypersensitivity reactions
    • Patient with known hypersensitivity to dextromethorphan
    • Use with a monoamine oxidase inhibitor (MAOI) or within 14 days of stopping an MAOI
    • Prolonged QT interval, congential long QT syndrome, history suggestive or torsades de pointes, or heart failure
    • Complete atrioventricular (AV) block without implanted pacemaker, or patients at high risk of complete AV block
    • Concomitant use with drugs that both prolong QT interval and are metabolized by CYP2D6 (e.g. thioridazine or pimozide)


  •  Starting dose: 1 capsule (20mg dextromethorphan and 10 mg quinidine) daily for 7 days
  • Day 8: increase to 1 capsule every 12 hours


  • Initial: 12 weeks
  • Renewal: 12 months
  • Renewal requires chart note documentation supporting positive response to therapy as evidenced by decrease in CNS-LS score by 3 points or greater from baseline AND if the request if for a dose increase, new dose does not exceed 40mg dextromethorphan and 20mg quinidine per day

Last review date: May 13, 2019

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