thoughtscape NP Psychiatry · Patient education
Dextromethorphan–quinidine
Nuedexta / Oral combination capsules
A guide for adults taking dextromethorphan–quinidine.
Follow the directions on your prescription and your provider's recommendations.
Formulations: Each capsule contains both medicines. It is not equivalent to a cough preparation or to the dextromethorphan–bupropion combination used for other conditions.
What it is used for
Nuedexta treats pseudobulbar affect: sudden episodes of laughing or crying that are difficult to control and out of proportion to the situation in certain neurologic conditions. This is different from depression or ordinary mood changes.
How it works
Dextromethorphan affects NMDA and sigma-1 signaling. Low-dose quinidine slows its breakdown so it can reach useful exposure; quinidine also creates important interaction and heart-rhythm risks.
What to expect over time
Track the frequency and severity of laughing or crying episodes and how they affect daily life. Your provider should periodically review whether treatment is still needed.
Taking your medication
- Follow the initial once-daily schedule, then the prescribed twice-daily schedule, generally beginning on day eight.
- Space twice-daily doses about 12 hours apart. Take with or without food.
- If you miss a dose, take it when you remember unless it is almost time for the next dose. Then skip it. Do not double a dose.
- Do not add cough medicines containing dextromethorphan without review.
When to get help
Emergency symptoms. Get emergency care for fainting, an irregular heartbeat, severe allergy, or fever with confusion and muscle stiffness.
Prompt medical advice. Report easy bruising, unusual bleeding, fever, yellow skin or eyes, or severe dizziness promptly.
If you feel unsafe or have thoughts of self-harm, call 911 or go to an emergency department.
Possible side effects
- Diarrhea or stomach discomfort
- Dizziness, weakness, or falls
- Swelling of the feet or ankles
Keeping track of treatment
Some side effects resolve with time; others may require a change of medication. Discuss persistent or bothersome side effects with your provider.
An ECG and electrolyte tests may be needed, especially with heart disease or interacting medicines. Report fainting, palpitations, unusual bruising, or signs of liver injury.
If you take too much
For a suspected overdose, call Poison Control at 1-800-222-1222 immediately, even if you feel well. Call 911 for a seizure, collapse, trouble breathing, or inability to wake.
Before you start
Do not use with certain heart-rhythm disorders, prolonged QT, heart failure, or certain conduction problems. Discuss any previous quinidine-related allergy, low platelets, hepatitis, or other immune reaction.
Discuss pregnancy, pregnancy plans, and breastfeeding with your provider. Treatment decisions should consider both the medication and the condition being treated.
Medicines and interactions
Review all your medications with your provider, including over-the-counter medicines and supplements. Have new medications checked before taking them.
Do not combine with an MAOI; allow the prescribed 14-day switching intervals. Certain QT-prolonging medicines that are also CYP2D6 substrates are contraindicated.
Quinidine strongly affects CYP2D6. Many antidepressants and other medications require review; serotonergic combinations can cause serotonin syndrome. Avoid unreviewed quinine or quinidine preparations.
Everyday tips
Record episodes and triggers to help assess benefit.
Take precautions against falls if dizzy and keep your full medication list current.
Your questions answered
Does it treat depression?
Its approved purpose is pseudobulbar affect. Depression can occur at the same time and may need separate treatment.
Can I use cough syrup instead?
No. The combination and exposure differ, and trying to reproduce it can cause harm.
Storage and safety
Keep medication in its labeled container, away from excess heat and moisture and out of reach of children and pets. Do not share it. Ask a pharmacy about disposal of unused medication.
Sources
About this information
Educational handout; does not replace your prescription or provider's recommendations.
Educational inclusion does not mean this medication or its indications are treated at this practice. Review the guide for your exact product with your prescriber or pharmacist.