Children's Hospital Colorado

Dextromethorphan (DM)

You can take a cough syrup with dextromethorphan if you have a cough that keeps you up at night. It can also help with a dry, hacky cough at the end of a cold or flu.


  • DM comes as a capsule, liquid, lozenge, or spray.
  • Use as directed on the label. Do not take more than the recommended amount in a day.

Extra Notes and Warnings:

  • This is an over-the-counter (OTC) drug. You can buy it at the drugstore.
  • DM comes alone or mixed in with other medicines.
  • Do not try to stop a cough if you are coughing up phlegm. Coughing is helpful in bringing up mucus from the lungs. This helps keep you from getting pneumonia.
  • Do not take DM if you have taken a MAO inhibitor in the past 2 weeks. These include: isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate).
  • Do not take this drug if you are taking venlafaxine (Effexor).
  • Research Notes: Some research shows DM helps a cough get better. Other research shows it has little to no effect.
  • Drug Abuse: DM has become a drug of abuse.

Common Brand Names:

  • Adult Tussin DM
  • Adult Tussin Cough - Capsule or Liquid
  • Robitussin Cough and Chest Congestion DM
  • Robitussin Long-Acting CoughGels
  • Vicks DayQuil Cough
  • Vicks Formula 44
  • Zicam Cough MAX

Other Names:

  • DM

Read the instructions and warnings on the package insert for all medicines you take.