Highlights for dextromethorphan
dextromethorphan Side Effects
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
- anxiety, irritable, or excited
- breathing problems
- fast, irregular heartbeat
- unusually weak or tired
Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):
- nausea, vomiting
- stomach upset
- trouble sleeping
dextromethorphan May Interact with Other Medications
Do not take this medicine with any of the following medications:
- ergot alkaloids like dihydroergotamine
- MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate
- stimulant medicines for attention disorders, weight loss, or to stay awake
This medicine may also interact with the following medications:
- barbiturates like phenobarbital
- certain heart medicines like metoprolol, digoxin, and methyldopa
- medicines for depression, anxiety, or psychotic disturbances
- medicines for sleep
- medicines to treat blood pressure
- muscle relaxers
- other medicines for cold, cough, or allergy
- some medicines used for sleep during surgery
How to Use dextromethorphan
Take this medicine by mouth with a full glass of water. Follow the directions on the prescription label. Take with food or milk. Use a specially marked spoon or container to measure your dose. Household spoons are not accurate. Take your medicine at regular intervals. Do not take it more often than directed.
Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for children as young as 4 years old for selected conditions, precautions do apply.
Patients over 60 years old may have a stronger reaction and need a smaller dose.
They need to know if you have any of these conditions:
- enlarged prostrate
- heart disease
- high blood pressure
- if you have taken an MAOI like Carbex, Eldepryl, Marplan, Nardil, or Parnate in last 14 days
- lung or breathing disease, like asthma
- thyroid disease
- an unusual or allergic reaction to dextromethorphan, guaifenesin, phenylephrine, other medicines, foods, dyes, or preservatives
- pregnant or trying to get pregnant
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.
Talk to your doctor if your cough lasts for more than 1 week. If you have a high fever, skin rash, lasting headache, or sore throat, see your doctor.
Drink several glasses of water each day. This will help loosen mucus.
You may get drowsy or dizzy. 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. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.
Keep out of the reach of children.
Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Keep bottle tightly closed. Protect from light. Throw away any unused medicine after the expiration date.
Last Updated: June 4, 2015