Robitussin DM is an over-the-counter cough suppressant and expectorant. This medicine helps to control your cough and thin secretions, so it is more productive.

A combination of guaifenesin and dextromethorphan, it is widely available under the brand name Robitussin and the generic Tussin.

This article discusses Robitussin DM cough syrup, its uses, and potential side effects. It also includes dosing information and warnings.

Common Uses

The ingredients in this medicine help to loosen mucus and suppress coughing. People commonly take this medicine for coughs associated with colds, allergies, the flu, and other respiratory illnesses.

It should not be used in children under 6 without talking to the child’s doctor first. 

Robitussin DM and its generic counterparts contain dextromethorphan HBr 10mg, which is a cough suppressant, and guaifenesin 100mg, which is an expectorant.

Dosing

  • Adults 12 and older: Two teaspoons every four hours as needed for cough. Do not take more than six doses in 24 hours.Children ages 6 to 12: One teaspoon every four hours. Do not take more than six doses in 24 hours.

Side Effects

Every medication has the potential to cause side effects. Most are minor and the benefits outweigh the risks.

  • Drowsiness or dizzinessHives or skin rashNausea, stomach pain or vomiting

Rare but serious side effects that should be reported to your healthcare provider immediately:

  • ConfusionExcitement, nervousness or restlessnessSevere nausea and vomitingSlurred speechSeizures or convulsions - in childrenShakey movements - in childrenSlow or troubled breathing - in children

Warnings

Do not use this medication if you are taking an MAOI (medication for depression, psychiatric, emotional conditions or Parkinson’s disease) or for two weeks after stopping an MAOI.

Ask a healthcare provider before using this medicine if you have a chronic cough that is caused by asthma, smoking, or emphysema.

Talk to your healthcare provider prior to taking this medicine if you are pregnant or breastfeeding as well.

If you have a cough that produces a lot of mucus, taking a cough suppressant can be problematic. Suppressing the cough can lead to secondary infections such as pneumonia because the mucus sits in the lungs rather than being expelled by coughing.

Stop use and ask a healthcare provider if:

  • Pain or cough worsens or lasts more than seven daysCough occurs with fever, headache, or rash that won’t go away

Do not give Robitussin or other cough suppressants to children under 6.

Misuse and Overdose

A National Institute on Drug Abuse survey found that 3% of high school students admit to misusing dextromethorphan (DXM). In high doses, DXM can cause hallucinations, psychosis, agitation, and possibly even overdose.

Frequently Asked Questions

  • What does Robitussin DM do?
  • Robitussin DM is a cough medicine. It contains an expectorant (guaifenesin) and a cough suppressant (dextromethorphan). Robitussin DM helps to thin mucus and calm a cough.
  • What is the difference between plain Robitussin and Robitussin DM?
  • The active ingredient in plain Robitussin is guaifenesin. Robitussin DM also contains an additional medication, dextromethorphan, that helps to quiet the cough reflex. The DM stands for dextromethorphan.
  • Who should not take Robitussin DM?
  • Robitussin DM should not be given to children under 6 years of age. Do not use Robitussin if you are taking an MAOI (medication for depression, psychiatric, emotional conditions, or Parkinson’s disease).If you have a chronic cough that is caused by asthma, smoking, or emphysema, talk to your healthcare provider before taking Robitussin DM.
  • Is Robitussin DM for sleep?
  • Robitussin DM is not specifically marketed for sleep. However, if you have a cough that is keeping you awake, the dextromethorphan in the cough medicine can help suppress the cough so you can sleep.Another formulation, Robitussin Nighttime DM, may make you sleepy. It contains the antihistamine doxylamine succinate instead of guaifenesin, which can cause drowsiness.
  • Is Robitussin DM good for dry cough?
  • Yes, Robitussin DM can be used to treat a dry cough. Dextromethorphan is a cough suppressant that helps to quiet a dry cough.

Robitussin DM is a cough medicine. It contains an expectorant (guaifenesin) and a cough suppressant (dextromethorphan). Robitussin DM helps to thin mucus and calm a cough. 

The active ingredient in plain Robitussin is guaifenesin. Robitussin DM also contains an additional medication, dextromethorphan, that helps to quiet the cough reflex. The DM stands for dextromethorphan.

Robitussin DM should not be given to children under 6 years of age. Do not use Robitussin if you are taking an MAOI (medication for depression, psychiatric, emotional conditions, or Parkinson’s disease).

Robitussin DM is not specifically marketed for sleep. However, if you have a cough that is keeping you awake, the dextromethorphan in the cough medicine can help suppress the cough so you can sleep.

Yes, Robitussin DM can be used to treat a dry cough. Dextromethorphan is a cough suppressant that helps to quiet a dry cough.