Nuedexta (Dextromethorphan And Quinidine) – Side Effects, Interactions, Uses, Dosage, Warnings

Dextromethorphan and quinidine is a combination medicine used to treat involuntary outbursts of crying or laughing in people with certain neurological disorders, including multiple sclerosis and amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease).

Dextromethorphan and quinidine may also be used for purposes not listed in this medication guide.


What is Nuedexta (Dextromethorphan And Quinidine) used for?

  • Pseudobulbar Affect


What is the most important information I should know about Nuedexta (Dextromethorphan And Quinidine)?

You should not take this medicine if you are allergic to dextromethorphan or quinidine, or if you have:

  • heart failure;
  • a history of life-threatening heart rhythm disorder;
  • long QT syndrome (in you or a family member);
  • a serious heart condition called "AV block" (unless you have a pacemaker); or
  • if you also use mefloquine, quinidine, or quinine.

You also should not take dextromethorphan and quinidine if you have ever had any of the following problems caused by taking mefloquine, quinidine, or quinine:

  • bruising or bleeding;
  • hepatitis;
  • an allergic reaction; or
  • lupus-like symptoms (joint pain, fever, skin rash on your cheeks).

Do not use dextromethorphan and quinidine if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others. After you stop taking dextromethorphan and quinidine, you must wait at least 14 days before you start taking an MAOI.

Dextromethorphan and quinidine can cause a serious heart problem. You should not take dextromethorphan and quinidine if you also use certain other medicines for infections, asthma, heart problems, high blood pressure, depression, mental illness, cancer, malaria, or HIV.

Be sure your doctor knows if you also take stimulant medicine, opioid medicine, herbal products, or medicine for depression, mental illness, Parkinson's disease, migraine headaches, serious infections, or prevention of nausea and vomiting. These medicines may interact with dextromethorphan and quinidine and cause a serious condition called serotonin syndrome.

Tell your doctor if you have ever had:

  • heart disease, high blood pressure, coronary artery disease;
  • slow heartbeats or any type of heart rhythm disorder;
  • an electrolyte imbalance (such as low levels of potassium or magnesium in your blood);
  • myasthenia gravis; or
  • trouble with balance or walking.

Tell your doctor if you are pregnant or breastfeeding.

Dextromethorphan and quinidine is not approved for use by anyone younger than 18 years old.

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Side Effects

What are the side effects of Nuedexta (Dextromethorphan And Quinidine)?

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using this medicine and call your doctor at once if you have:

  • fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out);
  • easy bruising or bleeding (nosebleeds, bleeding gums);
  • pain or burning when you urinate;
  • liver problems–fever, right-sided upper stomach pain, vomiting, loss of appetite, yellowing of your skin or eyes, and not feeling well; or
  • lupus-like symptoms–muscle or joint pain, flu symptoms, chest pain, and a rash or patchy skin color that worsens in sunlight.

Seek medical attention right away if you have symptoms of serotonin syndrome, such as: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea.

Common side effects may include:

  • dizziness, weakness;
  • diarrhea, gas, vomiting;
  • swelling in your hands or feet;
  • flu symptoms, cough; or
  • abnormal liver function tests.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Pregnancy & Breastfeeding

Can I take Nuedexta (Dextromethorphan And Quinidine) if I’m pregnant or breastfeeding?

Risk cannot be ruled out
Based on FDA pregnancy categories

Tell your doctor if you are pregnant or breastfeeding.


What drugs and food should I avoid while taking Nuedexta (Dextromethorphan And Quinidine)?

Avoid driving or hazardous activity until you know how this medicine will affect you. Your reactions could be impaired. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Dizziness can cause falls, accidents, or severe injuries.

Grapefruit may interact with dextromethorphan and quinidine and lead to unwanted side effects. Avoid the use of grapefruit products.

Ask a doctor or pharmacist before using any cough or cold medication that may contain dextromethorphan. Taking certain products together can cause you to get too much dextromethorphan. Check the label of medicines such as Delsym, Robitussin Maximum Strength, Vicks 44, and others.

Dosage Guidelines & Tips

How to take Nuedexta (Dextromethorphan And Quinidine)?

Use Nuedexta (Dextromethorphan And Quinidine) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Dextromethorphan and quinidine is usually taken once per day for 7 days, and then once every 12 hours. Follow your doctor's dosing instructions very carefully.

You may take dextromethorphan and quinidine with or without food.

Your doctor will need to check your progress on a regular basis. You may need medical tests to help your doctor determine how long to treat you with dextromethorphan and quinidine.

Store at room temperature away from moisture and heat.

What should I do if I missed a dose of Nuedexta (Dextromethorphan And Quinidine)?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Do not take more than 2 capsules in a 24-hour period.

Overdose Signs

What happens if I overdose on Nuedexta (Dextromethorphan And Quinidine)?

Overdose can cause severe dizziness, confusion, double vision, ringing in your ears, hearing loss, vomiting, fast or irregular heart rate, weak or shallow breathing, or seizure (convulsions).

If you think you or someone else may have overdosed on: Nuedexta (Dextromethorphan And Quinidine),  call your doctor or the Poison Control center

(800) 222-1222

If someone collapses or isn't breathing after taking Nuedexta (Dextromethorphan And Quinidine), call 911



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Color: red

Shape: capsule

Imprint: DMQ 20-10

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