Nuedexta Indication, Dosing, Price, Mechanism of Action | Lisa Binsin, PharmD | RxEconsult

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Nuedexta Indication, Dosing, Price Category: Multiple Sclerosis by - September 12, 2013 | Views: 9519 | Likes: 1 | Comment: 3  

Nuedexta | dextromethorphan and quinidine

Medication Class: CNS agents; NMDA Receptor Antagonists
Manufacturer: Avanir Pharmaceuticals, Inc.
Approval Date: October 2010

Nuedexta (dextromethorphan and quinidine) Uses, Side effects, dosage, Interactions

What is Nuedexta and how does it work

Nuedexta is a combination of dextromethorphan and quinidine. Dextromethorphan is a sigma-1 receptor agonist and uncompetitive NMDA receptor antagonist. The exact mechanism by which dextromethorphan exerts its effects in patients with PBA is unknown but it is thought to act on areas of the brain responsible for emotional responses. Quinidine increases blood levels of dextromethorphan by inhibiting the action of liver enzymes that break down dextromethorphan. Nuedexta is not an antidepressant and it should only be used specifically for pseudobulbar affect.

What does Nuedexta treat

It is FDA-approved for pseudobulbar affect (PBA) characterize by involuntary, sudden, and frequent episodes of laughing and/or crying.

How well does Nuedexta work

The efficacy of Nuedexta was demonstrated in a 12-week trial. 107 patients were on Nuedexta (dextromethorphan 20 mg/quinidine 10 mg), 110 patients on Nuedexta (dextromethorphan 30 mg/quinidine 10 mg), and 109 patients on placebo (sugar pill). Participants had an underlying amyotrophic lateral sclerosis (ALS) or multiple sclerosis. The primary outcome that was measured was laughing and crying episodes.

Results: The trial looked at and analyzed the total laughing and crying episodes over the 12 weeks. There was a significant reduction in laughing and crying episodes with patients on Nuedexta versus placebo.

What are interesting facts about Nuedexta

  • Nuedexta is currently the only FDA-approved drug for pseudobulbar affect
  • It can only be used to treat symptoms of uncontrollable laughing or crying and cannot be used to treat other symptoms.
  • Dextromethorphan is commonly used for treating cough.
  • Quinidine is used for treating abnormal heart rhythm. 

What is the dosage of Nuedexta

Dosage forms: capsule containing 20 mg dextromethorphan hydrobromide and 10 mg quinidine sulfate in a brick red gelatin capsule with “DMQ/20-10” printed in white ink on the capsule.

Dosing: One capsule daily by mouth for the initial seven days of therapy and one capsule every 12 hours starting on the eighth day onward.

What are the side effects of Nuedexta

Common: diarrhea, dizziness, cough, vomiting, asthenia (lack of energy or abnormal physical weakness), peripheral edema, urinary tract infection, influenza, flatulence

Severe: Thrombocytopenia (lower than normal platelets which can lead to bleeding), hepatitis (inflammation of the liver), QT prolongation (abnormal heart beats), left ventricular hypertrophy or dysfunction

Drug Interactions

Monoamine oxidase inhibitors (MAOIs) are drugs commonly used in the treatment of depression, Parkinson’s disease, and other disorders. Taking Nuedexta with MAOIs puts the patient at risk for serotonin syndrome which typically occur within several hours and include symptoms such as agitation or restlessness, confusion, rapid heart rate and high blood pressure, dilated pupils, and muscle twitching.

Examples of MAOIs include:

Marplan (isocarboxazid)

Nardil (phenelzine)

Emsam (selegiline)

Parnate (tranylcypromine)

Selective serotonin reuptake inhibitor (SSRIs) and Tricyclic Antidepressants

Examples of SSRI and TCA include:

Desipramine( tricyclic antidepressant): Nuedexta can increase desipramine dose 8-fold, therefore, dose adjustment is necessary based on clinical response.

Paroxetine (selective serotonin reuptake inhibitor): Nuedexta can increase paroxetine drug concentration 2-fold, thus dose reduction may also be warranted.

Cardiovascular Medications

Patients with cardiovascular disease (any type of heart disease) need to be careful while taking Nuedexta since it can cause QT prolongation, which is an abnormality in the heart’s electrical impulse. In other words, it can cause irregular heartbeats.

Examples of cardiovascular medications include digoxin. Nuedexta increases digoxin levels in the blood. 

What is the price of Nuedexta

The cost of Nuedexta is $586.80/month

How to obtain prescription assistance for Nuedexta

Patients can enroll in a savings program where patients pay no more than $30 if they have private insurance. The program is not valid for cash-paying patients.

References

Nuedexta package insert

 

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