Mixing DayQuil and Ketamine (ket)
Low risk, increased effect
Low risk of harm, but the effects amplify each other. Doses that are fine alone can be far too much together.
Can you take DayQuil with Ketamine?
DayQuil contains acetaminophen and DXM. The most concerning part is DayQuil (DXM) with Ketamine: both substances primarily exert their effects through NMDA antagonism. Currently, there is no evidence regarding mechanisms that might reduce these effects. MixSafe rates DayQuil with Ketamine as "Low risk, increased effect" — low risk of harm, but the effects amplify each other. Doses that are fine alone can be far too much together. Sources: the Drug Facts labels on DailyMed, the TripSit combination chart and MixSafe research. Educational information, not medical advice.
What is in it
- DayQuil
- Acetaminophen + DXM. DayQuil also contains phenylephrine, a decongestant, and DayQuil Severe adds guaifenesin, an expectorant. MixSafe has no data for either.
Ingredient by ingredient
DayQuil (DXM) + KetamineLow risk, increased effect
Low risk of harm, but the effects amplify each other. Doses that are fine alone can be far too much together.
Both substances primarily exert their effects through NMDA antagonism. Currently, there is no evidence regarding mechanisms that might reduce these effects.
Source: TripSit drug combination chart
DayQuil (Acetaminophen) + KetamineLow risk, no synergy
Neither substance is expected to meaningfully change the other. Both still carry their own individual risks.
No specific interaction is documented. Acetaminophen's main risk is dose-dependent liver injury, so the thing to watch in any combination is total daily intake across all products (roughly 4g/24h) and anything else straining the liver.
Sources: Prescott LF. Paracetamol, alcohol and the liver. Br J Clin Pharmacol. 2000 · Acetaminophen: A Liver Killer or Thriller
- Vicks DayQuil Cold & Flu LiquiCaps, Drug Facts label. DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=efb982d4-93d0-815f-e053-2995a90a82dd
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.
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