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 temperature, between 68 F to 77 F (20 C to 25 C). Protect dextromethorphan capsules from light, and 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
  • Nausea, vomiting, or 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 Canada, you 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 common, the most serious side effects of dextromethorphan are described below, along with what to do if they happen.

Severe Allergic Reactions. Dextromethorphan may cause allergic reactions, which 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 face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or 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 dextromethorphan, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and 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 suspension, use an accurate measuring device to measure your dose, such 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 days, stop taking dextromethorphan and call your healthcare provider.

You should not use dextromethorphan for a cough with a fever, rash, or 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) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if dextromethorphan is right for you.

In particular, make 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, asthma, or 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 dizziness, drowsiness, or 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) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are taking any monoamine oxidase inhibitor (MAOI) within the past 2 weeks, which 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 Dextromethorphan 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 dextromethorphan, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

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

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