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Uses

What is dextromethorphan used for?

Dextromethorphan is commonly used to reduce cough caused by common cold or inhaled allergens or that makes it hard for you to fall asleep.

Dextromethorphan may also be used for other conditions as determined by your healthcare provider.

How does dextromethorphan work (mechanism of action)?

Dextromethorphan reduces the urge to cough by slowing the activity in certain areas of the brain.

How is dextromethorphan supplied (dosage forms)?

Dextromethorphan is available in the following dosage forms that are taken by mouth.

  • 15 mg liquid filled capsules
  • 15 mg tablets
  • 30 mg/5 mL extended-release oral suspension
  • 15 mg/10 ml liquid

How should I store dextromethorphan?

Dextromethorphan should be stored at room temperaturebetween 68 F to 77 F (20 C to 25 C). Protect dextromethorphan capsules from lightand do not expose them to temperatures above 104 F (40 C). 

Side Effects

What are the most common side effects of dextromethorphan?

The most common side effects of dextromethorphan are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Dizziness
  • Drowsiness
  • Nauseavomitingor constipation
  • Confusion
  • Nervousness

There may be other side effects of dextromethorphan that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S.you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canadayou can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of dextromethorphan?

While less commonthe most serious side effects of dextromethorphan are described belowalong with what to do if they happen.

Severe Allergic Reactions. Dextromethorphan may cause allergic reactionswhich can be serious. Stop taking dextromethorphan and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the facelipsmouthtongueor throat
  • Trouble swallowing or throat tightness
  • Itchingskin rashor pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizzinessfeeling lightheadedor fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use dextromethorphan?

Allergies to Ingredients. People who are allergic to any of the following should not take dextromethorphan.

  • Robitussin
  • Creomulsion 
  • Delsym
  • Dextromethorphan
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific dextromethorphan products they stock.

Drug Interactions. Dextromethorphan should not be taken while you are using certain other medicines. Before taking dextromethorphantell your healthcare provider about any prescription or over-the-counter (OTC) medicinesvitamins/mineralsherbal productsand other supplements you are using. See the Interactions section for more details.

What should I know about dextromethorphan before using it?

Keep dextromethorphan out of the reach of children.

If you are taking dextromethorphan oral liquid or extended-release oral suspensionuse an accurate measuring device to measure your dosesuch as a dosing cup provided with the medicine. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Use the dosing cup provided with the product or ask your pharmacist to recommend an appropriate measuring device.

Shake dextromethorphan extended-release oral suspension well before taking it.

If your cough lasts more than 7 daysstop taking dextromethorphan and call your healthcare provider.

You should not use dextromethorphan for a cough with a feverrashor headache that will not go away. Talk with your healthcare provider if you have concerns.

Dextromethorphan can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how dextromethorphan affects you.

What should I tell my healthcare provider before using dextromethorphan?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicinesvitamins/mineralsherbal productsand other supplements you are using. This will help them determine if dextromethorphan is right for you.

In particularmake sure that you discuss any of the following.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

  • Chronic cough that occurs with smoking, asthmaor emphysema
  • Cough that occurs with too much mucus

Pregnancy. It is not known if or how dextromethorphan could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant.

Breastfeeding. It is not known if dextromethorphan passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.

Interactions

Does dextromethorphan interact with foods or drinks?

There are no known interactions between dextromethorphan and foods or drinks.

It is unknown if drinking alcohol will affect dextromethorphan. The risk of dizzinessdrowsinessor confusion may be increased if you drink alcohol while taking dextromethorphan.

Does dextromethorphan interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicinesvitamins/mineralsherbal productsand other supplements you are using.

In particularmake sure that you discuss if you are taking any monoamine oxidase inhibitor (MAOI) within the past 2 weekswhich is a medicine usually used for depression or Parkinson’s disease.

This may not be a complete list of medicines that can interact with dextromethorphan. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much dextromethorphan?

If you or someone else has taken too much dextromethorphanget medical help right awaycall 911or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of dextromethorphan?

If you miss a dosetake it as soon as you remember. If it is almost time for your next doseskip the missed dose and only take the next dose. Do not take double or extra doses.