In our latest question and answer, our pharmacist discusses whether or not you can take Dayquil with Nyquil.
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Can I take Nyquil and Dayquil together?
Short answer: You can take them Nyquil & Dayquil together, but not at the same time. In this context, the “sametime” means any time within 4 hours of one another.
Dayquil Cold & Flu (the most common version) containsthree active ingredients: acetaminophen, a pain reliever; dextromethorphan, acough suppressant; and phenylephrine, a decongestant. Phenylephrine is a mildstimulant, and can make some people jittery, which is less of a problem for daytimeuse. Dayquil does not contain alcohol.
Nyquil Cold & Flu also contains three active ingredients:acetaminophen, dextromethorphan, and doxylamine, an antihistamine related to theactive ingredient in Benadryl (diphenhydramine). Doxylamine can make youprofoundly drowsy, so it’s better suited for nighttime use. Nyquil Liquid alsocontains 10% alcohol, so one 30 mL dose contains a similar amount of alcohol asa shot glass of wine. The liquicaps do NOT contain alcohol.
The labeling on both products states not to take more than 4doses in 24 hours. This is based mainly around the acetaminophen content, whichis 650 mg per dose of either product (a dose of either product is 30 mL or 2liquicaps)
Acetaminophen, a very common pain and fever reducer (foundin Tylenol, for example), is broken down in the liver after you’ve taken it. Oneof the chemicals it’s broken down into is toxic to the liver, but the body hasa process for making it non-toxic and getting rid of it. This process, however,has a limited capacity, and once that capacity runs out, the toxic byproductcan build up and cause severe liver damage (like, transplant-level, in seriouscases).
That limit in a healthy, 150 lb person is around 4000 mg perday of acetaminophen from ALL sources, including pain relievers, prescriptionproducts, cough/cold/flu medications. But for some people the limit may belower. To keep yourself well in the clear, It’s best to take only the lowestamount necessary, and stay around 3000 mg/day maximum. If you have liverimpairment or chronic diseases, talk to your doctor before using acetaminophenin any amount.
Four doses of Dayquil or Nyquil would deliver 2600 mg ofacetaminophen per day, so you can see how quickly your daily dose adds up. Youdon’t have to be afraid of the drug, but you do have to be smart and read yourlabels for all your medications. Youshould also avoid drinking heavily (or ideally, at all) while usingacetaminophen, meaning more than 2 drinks/day for men, 1 drink/day for women.
There you have it. A good place to start if you want to useboth products might be two doses of Dayquil and one dose of Nyquil daily. Ifyou need additional relief, you could instead take 3 doses of Dayquil, 1 doseof Nyquil, or two and two…whatever helps you avoid nighttime sleeplessness ordaytime drowsiness. Just be sure to always wait at least 4 hours between anydose of these products. Thanks for your question!
PS: If you’re taking the liquid form, use the dosing cup to measure 30 mL. Your cereal spoon is notaccurate!