Nuedexta (dextromethorphan HBr and quinidine sulfate) Tablet 20 mg

Nuedexta is a combination medication consisting of dextromethorphan hydrobromide (HBr) and quinidine sulfate, indicated primarily for the treatment of pseudobulbar affect (PBA), a condition characterized by sudden, uncontrollable episodes of laughing or crying that are disproportionate to the patient’s actual emotional state. PBA is commonly seen in individuals with neurological conditions such as amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), or traumatic brain injuries.

How It Works

Nuedexta works through a combination of its two active ingredients, dextromethorphan and quinidine, which together help regulate emotional expression in patients with PBA.

Mechanism of Action

1. Dextromethorphan (DM):
   • Dextromethorphan is a cough suppressant commonly found in over-the-counter medications. In Nuedexta, it acts on the central nervous system (CNS) by inhibiting the NMDA receptors (N-methyl-D-aspartate) in the brain, which are involved in the regulation of mood and behavior. DM is also thought to increase serotonin and other neurotransmitter activity, thereby stabilizing emotional responses.
2. Quinidine:
   • Quinidine is a medication traditionally used to treat certain types of heart arrhythmias. In Nuedexta, it serves a different role—inhibiting the metabolism of dextromethorphan by blocking the enzyme CYP2D6. By slowing down the breakdown of dextromethorphan in the liver, quinidine increases the concentration of dextromethorphan in the blood, prolonging its effects on the brain.

Together, these actions help regulate emotional expression, reducing the frequency and severity of inappropriate episodes of laughing or crying associated with PBA.

Side Effects

While Nuedexta is effective for managing PBA, it may cause several side effects. These can vary in severity and frequency depending on individual reactions to the medication.

Common Side Effects

• Dizziness:
  • Feeling lightheaded or unsteady is a common side effect.
• Diarrhea:
  • Gastrointestinal upset, including diarrhea, may occur during treatment.
• Fatigue:
  • Some patients report feeling unusually tired or fatigued while on Nuedexta.
• Cough:
  • Although dextromethorphan is typically used to suppress cough, some individuals may experience an increased cough.
• Swelling in the extremities:
  • Fluid retention can cause swelling, particularly in the feet and ankles.
• Urinary tract infection (UTI):
  • Nuedexta may increase the risk of UTIs in some patients.

Serious Side Effects

• Heart Rhythm Problems (QT Prolongation):
  • Quinidine can cause QT prolongation, a condition where the heart’s electrical system takes longer than usual to recharge between beats. This can lead to arrhythmias, which may be life-threatening if left untreated.
• Allergic Reactions:
  • Some patients may experience serious allergic reactions, including swelling of the face, tongue, or throat, difficulty breathing, or hives.
• Liver Function Changes:
  • Nuedexta may cause liver enzyme levels to increase, potentially indicating liver damage.
• Severe Dizziness or Fainting:
  • Some individuals may experience significant drops in blood pressure, causing severe dizziness or fainting episodes.

Indications

Nuedexta is primarily indicated for the following condition:

• Pseudobulbar Affect (PBA):
  • Nuedexta is FDA-approved for the treatment of pseudobulbar affect, particularly in patients with neurological conditions like amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), Parkinson’s disease, stroke, and traumatic brain injuries.

Contraindications

Nuedexta should not be used in certain patients due to the risk of serious health complications. The following are contraindications for Nuedexta:

• Heart Conditions:
  • Nuedexta is contraindicated in patients with prolonged QT intervals, torsades de pointes, or complete heart block without a pacemaker, as quinidine may worsen these conditions.
• Use of MAO Inhibitors:
  • Patients currently taking or having taken monoamine oxidase inhibitors (MAOIs) in the past 14 days should avoid Nuedexta, as it may lead to serious drug interactions.
• Liver Disease:
  • Patients with severe liver impairment should not take Nuedexta because the liver metabolizes both dextromethorphan and quinidine.
• Quinidine Allergy:
  • Patients who have experienced allergic reactions to quinidine or related compounds (quinine, mefloquine) should avoid using Nuedexta.
• Concomitant Drugs that Prolong QT Interval:
  • Nuedexta should not be used with other medications that are known to prolong the QT interval or cause arrhythmias.

Pricing Information

The price of Nuedexta can vary significantly depending on the country, pharmacy, and health insurance coverage. Below is a table with approximate prices in different regions:

Country	Price (per pack of 60 tablets)	Reference
United States	$700 – $900	GoodRx
United Kingdom	£600 – £750	NHS BNF
Germany	€650 – €800	Apotheke
Canada	CAD $850 – $1,000	Canada Drugs
Australia	AUD $1,000 – $1,200	PBS

Top 5 Global Brands

While Nuedexta is manufactured by Avanir Pharmaceuticals, several other global brands contribute to the broader market for neurological and neuropsychiatric therapies. Below are five of the most prominent brands in this field:

1. Avanir Pharmaceuticals:
   • As the producer of Nuedexta, Avanir focuses on treatments for neurological conditions, including pseudobulbar affect and Alzheimer’s-related agitation.
2. Biogen:
   • A global leader in neuroscience, Biogen produces therapies for multiple sclerosis, amyotrophic lateral sclerosis, and other neurological diseases.
3. Novartis:
   • Novartis is heavily invested in developing treatments for neurological conditions, with a robust portfolio addressing multiple sclerosis and other neurodegenerative diseases.
4. Pfizer:
   • With a significant presence in neurology and psychiatry, Pfizer offers treatments for a variety of neurological and psychological disorders.
5. Roche:
   • Roche is known for its pioneering work in neurology, particularly in areas like Alzheimer’s disease and neurodegenerative conditions.