Dextromethorphan; Quinidine oral capsules

Dextromethorphan and quinidine combine to treat uncontrollable and frequent episodes of laughing and/or crying caused by pseudobulbar affect. This medication comes in a capsule form. You take it by mouth with a glass of water as directed. If it upsets your stomach, take it with food.

What is this medication?

DEXTROMETHORPHAN; QUINIDINE (dex troe meth OR fan; KWIN i deen) is a combination of two medicines used to treat pseudobulbar affect (PBA), a condition that causes uncontrollable, sudden, and frequent episodes of laughing and/or crying.

This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.



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What should I tell my care team before I take this medication?

They need to know if you have any of these conditions:

  • dementia
  • heart disease
  • history of drug abuse or alcohol abuse problem
  • history of low blood counts caused by a medicine
  • history of irregular heartbeat
  • kidney disease
  • liver disease
  • low levels of magnesium or potassium in the blood
  • myasthenia gravis
  • an unusual or allergic reaction to dextromethorphan, quinidine, other medicines, foods, dyes, or preservatives
  • pregnant or trying to get pregnant
  • breast-feeding

How should I use this medication?

Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. You can take it with or without food. If it upsets your stomach, take it with food. Take your medicine at regular intervals. Do not take it more often than directed. Do not stop taking except on your doctor's advice.

Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.

NOTE: This medicine is only for you. Do not share this medicine with others.


What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medication?

Do not take this medicine with any of the following medications:

  • certain antipsychotics like chlorpromazine, haloperidol, pimozide, risperidone, and thioridazine
  • certain medicines for irregular heart beat like dofetilide, encainide, flecainide, mexiletine, propafenone, and quinidine
  • cisapride
  • dolasetron
  • dronedarone
  • MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate
  • mefloquine
  • quinine

This medicine may also interact with the following medications:

  • alcohol
  • aprepitant
  • certain antivirals for HIV or hepatitis
  • certain medicines for depression like amitriptyline, citalopram, desipramine, escitalopram, fluoxetine, fluvoxamine, nefazodone, paroxetine, and sertraline
  • certain medicines for fungal infections like fluconazole, itraconazole, and ketoconazole
  • certain antibiotics like clarithromycin, erythromycin, and telithromycin
  • codeine
  • digoxin
  • diltiazem
  • grapefruit juice
  • hydrocodone
  • memantine
  • other medicines that prolong the QT interval (an abnormal heart rhythm)
  • verapamil

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.


What should I watch for while using this medication?

Tell your doctor or healthcare professional if your symptoms do not start to get better or if they get worse. Visit your doctor or health care professional for regular checks on your progress.

You may get dizzy. Contact your doctor right away if you feel faint or have fainting spells while taking this medicine. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Avoid alcoholic drinks; they can make you more dizzy.

What side effects may I notice from receiving this medication?

Side effects that you should report to your doctor or health care professional as soon as possible:

  • allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
  • breathing problems
  • changes in vision
  • decreased hearing
  • lupus-like symptoms such as sensitivity to light; swollen or painful joints; skin rash; unexplained fever; anemia; unusually weak or tired
  • signs and symptoms of a dangerous change in heartbeat or heart rhythm like chest pain; dizziness; fast, irregular heartbeat; palpitations; feeling faint or lightheaded; falls; breathing problems
  • signs and symptoms of liver injury like dark yellow or brown urine; general ill feeling or flu-like symptoms; light-colored stools; loss of appetite; nausea; right upper belly pain; unusually weak or tired; yellowing of the eyes or skin
  • signs and symptoms of serotonin syndrome like confusion; increased sweating; fever; tremor; stiff muscles; diarrhea
  • unusual bleeding or bruising

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

  • cough
  • diarrhea
  • dizziness
  • drowsiness

This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Where should I keep my medication?

Keep out of the reach of children.

This medicine may cause accidental overdose and death if it taken by other adults, children, or pets. Mix any unused medicine with a substance like cat litter or coffee grounds. Then throw the medicine away in a sealed container like a sealed bag or a coffee can with a lid. Do not use the medicine after the expiration date.

Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F).

NOTE: This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.

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