NyQuil can be taken with or without food. However, if you find that it upsets your stomach or causes nausea when you take a dose, food may help to make it better tolerated.
Having said this, there are some studies that suggest that a few of the ingredients in NyQuil are more slowly absorbed if taken with food versus on an empty stomach. This may delay how quickly it begins to work. Overall though, food appears to have a very minimal impact which is why Vick's, the manufacturer of NyQuil, states it can be taken with or without food.
Now, the recommendation to take NyQuil with or without food doesn't apply to all drugs, just NyQuil in this case. It is important to always ask your doctor or pharmacist whether or not your medication should be taken with food.
Some medications, like several ones for your thyroid (e.g. levothyroxine) and osteoporosis (e.g. alendronate), are recommended to be taken on an empty stomach. Others, like calcium carbonate and Latuda, should be taken with food for better absorption.
NyQuil - Food Interactions
Let's go into more detail regarding eating food with NyQuil.
I always like to remind people that NyQuil contains more than one drug so you, so it is important to evaluate all of them when answering a question like this. NyQuil contains:
NyQuil Severe contains one additional drug, phenylephrine.
Let's take a look at how food interacts with each of these ingredients.
Food With Acetaminophen
Several studies report that although food doesn't significantly impact the overall analgesic activity of acetaminophen (i.e. how well it relieves pain), it may slow absorption of it. One study stated:
For rapid relief, acetaminophen should be taken in an empty stomach because food may slow the body absorption of acetaminophen. [For example] Co-administration of acetaminophen with pectin delays its absorption and onset.
And another stated the following:
Although food slowed the rate of absorption of both oral preparations, no significant difference in peak acetaminophen plasma concentration or time of peak concentration was observed as a function of age.
The point here is that food may slow the absorption of acetaminophen, so it may not work as quickly. This effect is likely fairly minimal though and shouldn't decrease how well it works to treat pain.
Food With Dextromethorphan
Dextromethorphan is the cough suppressant contained in NyQuil. Most studies report that food does not affect its absorption or overall effect.
However, some foods, like grapefruits, limes and Seville oranges can inhibit dextromethorphan metabolism, increasing concentrations of the drug. This may increase the risk of side effects.
So, while food, in general, is fine to mix with dextromethorphan, try to avoid citruses like grapefruit and lime.
Food With Doxylamine
Doxylamine is the antihistamine contained in NyQuil. It is a 'first-generation' antihistamine, similar to Benadryl. In addition to the alcohol that NyQuil contains, doxylamine is what causes you to feel tired after taking the medication.
Like dextromethorphan, food does not appear to have any effect on doxylamine. From one study:
High-fat, high-calorie food intake does not affect the kinetics of doxylamine in healthy subjects
Food With Phenylephrine
Phenylephrine is the decongestant in NyQuil Severe. It is not an ingredient in the original NyQuil formula.
Studies show that food has little effect on phenylephrine. One reported that it slowed the absorption of the drug, but not the total amount absorbed.
Overall, studies show that all of the ingredients contained in NyQuil and NyQuil Severe are not significantly altered by food intake. Only acetaminophen and phenylephrine appear to have their absorption rate slowed a little, but this isn't thought to decrease how well they work.
NyQuil can be taken with or without food. Food may delay absorption of the medication slightly (acetaminophen and phenylephrine specifically), but this shouln't have a significant impact on how well it works.
- Food-Drug Interactions. PubMed
- The effect of food on bromfenac, naproxen sodium, and acetaminophen in postoperative pain after orthopedic surgery.PubMed
- Food Effects on the Pharmacokinetics of Doxylamine Hydrogen Succinate 25 mg Film-Coated Tablets. PubMed
- An open-label, randomized, four-treatment crossover study evaluating the effects of salt form, acetaminophen, and food on the pharmacokinetics of phenylephrine. PubMed