Dextromethorphan; Quinidine
Dextromethorphan Hydrobromide, Quinidine Sulfate Oral capsule
What is this medicine?
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.
What should I tell my health care provider before I take this medicine?
They need to know if you have any of these conditions:
heart disease
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 medicine?
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've 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 medicine?
Do not take this medicine with any of the following medications:
arsenic trioxide
certain antipsychotics like chlorpromazine, clozapine, haloperidol, mesoridazine, olanzapine, perphenazine, pimozide, risperidone, sertindole, thioridazine, ziprasidone
certain medicines for irregular heart beat like amiodarone, bepridil, dofetilide, encainide, flecainide, propafenone, quinidine
certain medicines used to treat infections like chloroquine, clarithromycin, erythromycin, pentamidine, posaconazole
certain medicines used for nausea like dolasetron, droperidol, ondansetron, palonosetron
cisapride
cyclobenzaprine
MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate
mefloquine
methadone
quinine
ranolazine
This medicine may also interact with the following medications:
alcohol
aprepitant
certain antiviral medicines for HIV or AIDS
certain medicines for depression or anxiety
certain medicines for fungal infections like fluconazole, ketoconazole, and itraconazole
codeine
digoxin
diltiazem
grapefruit juice
hydrocodone
memantine
tacrolimus
telavancin
telithromycin
tetrabenazine
vardenafil
verapamil
vorinostat
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 medicine?
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 medicine?
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
changes in vision
chills
confusion
decreased hearing
fast or irregular heartbeat
feeling faint or lightheaded, falls
fever
muscle pain
ringing of the ears
sensitivity to light
unusual bleeding or bruising
unusually weak or tired
Side effects that usually do not require medical attention (Report these to your doctor or health care professional if they continue or are bothersome.):
cough
diarrhea
dizziness
drowsiness
headache
nausea, vomiting
stomach pain
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 medicine?
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.
Updated:  
March 21, 2017
Sources:  
U.S. FDA-approved Package Insert