Combination

Mixing DXM (robo) and NyQuil

DissociativeCombination
Verdict

Caution · DXM twice

DXM and NyQuil both contain dextromethorphan (DXM), the cough suppressant. The doses add up, and above the label amount DXM stops acting like cough medicine: dizziness, vomiting, a fast heartbeat, confusion and feeling detached from your body.

  1. Take one of them, not both. "DM" in a product's name (Robitussin DM, Mucinex DM) means it contains DXM.
What “Caution” means

Can you take DXM with NyQuil?

NyQuil contains acetaminophen, DXM and doxylamine. DXM and NyQuil both contain dextromethorphan (DXM), the cough suppressant. The doses add up, and above the label amount DXM stops acting like cough medicine: dizziness, vomiting, a fast heartbeat, confusion and feeling detached from your body. MixSafe rates DXM with NyQuil as "Caution" — carries risk that is worth understanding before combining. Reduce doses and do not use alone. Sources: the Drug Facts labels on DailyMed. Educational information, not medical advice.

What is in it

NyQuil
Acetaminophen + DXM + Doxylamine. Doxylamine is checked as diphenhydramine (Benadryl): both are sedating antihistamines of the same kind. NyQuil Severe also contains phenylephrine, a decongestant MixSafe has no data for.

DXM twice

Caution

DXM + NyQuil

What to do
  1. 01Take one of them, not both."DM" in a product's name (Robitussin DM, Mucinex DM) means it contains DXM.
Signs it is happening
  1. Dizziness, vomiting, or feeling drunk or detached
  2. A fast heartbeat, sweating, or running hot
Why this happens

DXM and NyQuil both contain dextromethorphan (DXM), the cough suppressant.

The doses add up, and above the label amount DXM stops acting like cough medicine: dizziness, vomiting, a fast heartbeat, confusion and feeling detached from your body.

Sources

Ingredient lists checked 2026-09-27. Formulas change and store brands differ, so the Drug Facts box on your own packet is the final word.

Think this is wrong, or know a better source? Send it.

Checking more than two?

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Related combinations

NyQuil with