Nuedexta (Dextromethorphan and Quinidine) – Oral

What Is Nuedexta?

Nuedexta (dextromethorphan and quinidine) is a prescription drug used to treat pseudobulbar affect (PBA) symptoms. PBA symptoms are sudden, frequent, and uncontrollable laughing or crying, in particular people with brain or nerve damage. 

Nuedexta is part of a drug class called n-methyl-d-aspartate (NMDA) receptor antagonist. It is available as a capsule containing 20 milligrams dextromethorphan hydrobromide and 10 milligrams quinidine sulfate.

Dextromethorphan binds to specific receptors in the brain that may cause PBA episodes. However, its exact mechanism of action is unknown. Quinidine blocks how quickly the body gets rid of dextromethorphan, increasing the level of dextromethorphan.

Drug Facts

Generic Name: Dextromethorphan and quinidine

Brand Name(s): Nuedexta

Drug Availability: Prescription

Therapeutic Classification: N-methyl-D-aspartate (NMDA) receptor antagonist

Available Generically: No

Controlled Substance: N/A

Administration Route: Oral

Active Ingredient: Dextromethorphan and quinidine

Dosage Form(s): Capsule

What Is Nuedexta Used For?

Nuedexta treats pseudobulbar affect symptoms, including frequent and sudden laughing or crying that occurs without your control. 

PBA may be seen in people with neurological (brain) damage, including those with extrapyramidal disorders (drug-induced movement disorders) or multiple sclerosis. It is, however, frequently misdiagnosed as depression or bipolar disorder.

An illustration with nuedexta (dextromethorphan and quinidine) drug information

Verywell / Zoe Hansen

How to Take Nuedexta

Take with or without food and as directed by your healthcare provider twice daily, 12 hours apart. Do not stop taking this medicine even if you feel better. Speak to your healthcare provider if you have any questions.

Avoid grapefruit juice while on this medication. Grapefruit juice may increase levels of quinidine. Also, avoid tonic water. Tonic water contains quinine.


It is best to store Nuedexta at room temperature (about 77 degrees Fahrenheit) in a dry place. However, you may keep it between cool and mildly hot temperatures during trips.

Keep your medications tightly closed and out of the reach of children and pets, ideally locked in a cabinet or closet.

Avoid pouring unused and expired drugs down the drain or in the toilet. Ask your pharmacist or healthcare provider about the best ways to dispose of this medicine. Visit the Food and Drug Administration (FDA) website to know where and how to discard unused and expired drugs. You may also find disposal boxes in your area. Ask your pharmacist or healthcare provider about the best ways to dispose of your medications.

If you plan to travel with Nuedexta, become familiar with your final destination's regulations. In general, be sure to make a copy of your Nuedexta prescription. If possible, keep your medication in its original container from your pharmacy with your name on the label. Ask your pharmacist or healthcare provider if you have any questions about traveling with your medicine.

How Long Does Nuedexta Take to Work?

Once ingested, dextromethorphan takes about three to four hours to peak, while quinidine takes about one to two hours. Check with your healthcare provider or pharmacist if you've any questions.

Off-Label Use

Agitation or aggression is an expected behavior most people with Alzheimer's disease may develop as their condition worsens. Nuedexta is used off-label to control agitation or aggression in Alzheimer's disease.

What Are the Side Effects of Nuedexta?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at or 800-FDA-1088.

Common Side Effects

Common side effects of Nuedexta include but are not limited to:

Severe Side Effects

Nuedexta can cause many side effects. Some may be life-threatening. Call your healthcare provider right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you have a medical emergency. Severe side effects include:

  • Fast or abnormal heartbeat
  • Passing out
  • Depression
  • Vision changes
  • Chills
  • Swollen glands
  • Swelling of legs or arms 
  • Lupus-like rash on the cheeks or body 
  • Liver problems like dark urine, light-colored stools, vomiting, or yellow skin
  • Bleeding like red, or tarry stools or bleeding from the gums
  • Serotonin syndrome 
  • Signs of an allergic reaction, like rash
  • QT prolongation (heart rhythm disorder)
  • Thrombocytopenia, which may be linked to quinidine use, resulting in severe to deadly reactions (Do not use this medicine if you have a history of immune-mediated thrombocytopenia while on medications like mefloquine or quinine.)

This is not an exhaustive list of all possible adverse effects. If you have any concerns, consult your doctor.

Abuse/misuse: People with a history of substance use disorder should be monitored for indicators of abuse/misuse (like the development of tolerance or drug-seeking behavior). Dextromethorphan abuse can result in loss of consciousness, heart arrhythmia, brain damage, or death.

Report Side Effects

Nuedexta may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Nuedexta Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (capsules):
    • For PBA or emotional incontinence:
      • Adults—One capsule once a day for the first 7 days of treatment. Then on day 8 and onwards, dose should be two capsules per day, taken as one capsule every 12 hours. Each capsule contains 20 milligrams (mg) of dextromethorphan and 10 mg of quinidine.
      • Children—Use and dose must be determined by your doctor.


The following modifications (changes) should be kept in mind when using Nuedexta:

Severe allergic reaction: Avoid using Nuedexta if you have a known allergy to it or its ingredients. Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.

Pregnancy: There is not enough information on the effects of this medicine in pregnant people. With the advice of your healthcare provider, you must weigh the benefit of taking this medicine during pregnancy with the risk to the unborn fetus. Discuss with your healthcare provider if you plan to become pregnant or are pregnant.

Breastfeeding: It is unknown if Nuedexta is present in breast milk. The benefits of nursing to the infant, treatment to the mother, and the risk of baby exposure should be considered when deciding to breastfeed during therapy. Talk with your healthcare provider if you plan to breastfeed, weigh the benefits and risks of taking Nuedexta while nursing, and the different ways available to feed your baby.

Adults over 65 years: This drug may increase the risk of falls in this population, even with short-term use. Also, due to the potential for heart issues (ex., QT prolongation), avoiding Nuedexta in older adults may be best. Healthcare providers must carefully evaluate older adults before starting this medicine. 

Missed Dose

If you accidentally forgot your Nuedexta dose, take it as soon as you remember. If it's already close to your next scheduled dose, skip the missed dose. Take the following dose at your next scheduled dosing time. Don't try to double up to make up for the missed dose.

Try to find ways that work for you to help yourself remember to keep your appointments and take your medication routinely. If you miss too many doses, Nuedexta might be less effective at treating or preventing your condition.

Overdose: What Happens If I Take Too Much Nuedexta?

Symptoms of suspected Nuedexta overdose may include:

  • Mild to moderate nausea
  • Dizziness
  • Low blood pressure
  • Light sensitivity
  • Double vision
  • Headache
  • Ringing in the ear
  • Hearing loss

If you think that you're experiencing an overdose or life-threatening symptoms, however, seek immediate medical attention.

What Happens If I Overdose on Nuedexta?

If you think you or someone else may have overdosed on Nuedexta, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Nuedexta, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood tests may be needed to check for unwanted effects.

If your symptoms do not improve or if they become worse, check with your doctor.

Do not use this medicine together with other products containing quinidine, quinine (Qualaquin®), or mefloquine (Lariam®). You should not take this medicine if you are also using pimozide (Orap®), thioridazine (Mellaril®), or an MAO inhibitor (MAOI) such as Eldepryl®, Marplan®, Nardil®, or Parnate® within the past 14 days. Also, allow at least 14 days after stopping this medicine before starting an MAO inhibitor (MAOI).

Stop using this medicine and check with your doctor right away if you have the following symptoms while taking this medicine: black, tarry stools; bleeding gums; blood in the urine or stools; chills; fever; lightheadedness; nausea or vomiting; pinpoint red spots on the skin; or unusual bleeding or bruising.

This medicine can cause changes in heart rhythms, such as a condition called QT prolongation. It may change the way your heart beats and cause fainting or serious side effects in some patients. Contact your doctor right away if you have any symptoms of heart rhythm problems, such as fast, pounding, or irregular heartbeats.

This medicine may cause some people to become dizzy, trouble in controlling movements, or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do other jobs that require you to be alert and well-coordinated.

Make sure your doctor knows about all the other medicines you are using. This medicine may cause a serious condition called serotonin syndrome when taken with medicine for depression (such as amitriptyline, clomipramine, doxepin, fluoxetine, imipramine, nortriptyline, Anafranil®, Elavil®, Prozac®, Sinequan®, or Tofranil®). Check with your doctor first before taking any other medicines.

This medicine will add to the effects of alcohol and other CNS depressants (medicines that make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for hay fever, allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; other medicines for seizures (e.g., barbiturates); muscle relaxants; or anesthetics, including some dental anesthetics. Check with your medical doctor or dentist before taking any of the above while you are using this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Nuedexta?

Avoid taking Nuedexta if you:

  • Have an allergy to dextromethorphan, quinine, mefloquine, quinidine, or any part of the formulation.
  • Have a history of quinine-, mefloquine-, or quinidine-induced thrombocytopenia (in which a drug destroys platelets), hepatitis, bone marrow depression (decreases blood cell production), or lupus-like syndrome.
  • Use Nuedexta with quinidine or other medicines containing quinidine, quinine, or mefloquine.
  • Take drugs that prolong the QT interval (e.g., pimozide, thioridazine).
  • Take monoamine oxidase inhibitors (MAOIs) or have taken MAOIs within the past two weeks.
  • Have heart issues like heart failure, prolonged QT interval (heart rhythm disorder), or history of torsade de pointe (heart rhythm disorder)
  • Have had an atrioventricular (AV) block without an implanted pacemaker.

What Other Medications Interact With Nuedexta?

Certain medications interact with Nuedexta and increase the risk of severe side effects. Use caution when taking Nuedexta with the following medications:

Talk with your pharmacist or healthcare provider for more detailed information about medication interactions with Nuedexta.

And be sure to talk with your healthcare provider about any other medicines you take or plan to take, including over-the-counter, nonprescription products, vitamins, herbs, or plant-based medicines.

What Medications Are Similar?

Other drugs similar to Nuedexta in the N-methyl-D-aspartate (NMDA) Receptor Antagonist drug class or used to treat pseudobulbar affect symptoms include:

  • Capron DM (dextromethorphan and pyrilamine)
  • Spravato (esketamine)
  • Prozac (fluoxetine)
  • Zoloft (sertraline)

This list is a list of drugs that may also be prescribed to treat pseudobulbar affect symptoms. It is not a list of medicines recommended to take with Nuedexta. You should not take these drugs together unless your halthcare provider tells you to. Ask your pharmacist or a healthcare practitioner if you have questions.

Frequently Asked Questions

  • What is Nuedexta used to treat?

    Nuedexta is used to treat symptoms of pseudobulbar affect, which includes sudden uncontrollable laughing or crying in certain people with nerve or brain damage.

  • What are the common side effects of Nuedexta?

    Some common side effects include:

    • Dizziness
    • Diarrhea
    • Cough
    • Vomitinig
    • Feeling weak or tired 
  • Can I drink grapefruit juice or tonic water while on Nuedexta?

    No, avoid grapefruit juice because it may increase quinidine levels in your body.  Also, avoid tonic water. Tonic water contains quinine.

How Can I Stay Healthy While Taking Nuedexta?

Experiencing frequent and sudden laughing and/or crying without control can be challenging. Taking Nuedexta can help control those symptoms. However, while on this medicine, be sure to:

  • Let your healthcare provider know all your health problems and medicines, including over-the-counter medications.
  • Avoid driving or any tasks that require you to be alert until you know how your body reacts to this medicine.
  • Tell your healthcare provider if you are pregnant, plan to get pregnant, or are breastfeeding.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Nuedexta label

  2. Ahmed A, Simmons Z. Pseudobulbar affect: prevalence and managementTher Clin Risk Manag. 2013;9:483-489. doi:10.2147/TCRM.S53906

  3. Millán-Calenti JC, Lorenzo-López L, Alonso-Búa B, de Labra C, González-Abraldes I, Maseda A. Optimal nonpharmacological management of agitation in Alzheimer's disease: challenges and solutions. Clin Interv Aging. 2016;11:175-184. Published 2016 Feb 22. doi:10.2147/CIA.S69484

By Queen Buyalos, PharmD
Queen Buyalos is a pharmacist and freelance medical writer. She takes pride in advocating for cancer prevention, overall health, and mental health education. Queen enjoys counseling and educating patients about drug therapy and translating complex ideas into simple language.