Is NyQuil (Or DayQuil) Safe To Take With Paxlovid?
In our latest question and answer, our pharmacist discusses the safety of taking NyQuil and DayQuil with Paxlovid.
I was prescribed Paxlovid and I'm reading about all these drug interactions it can have. Is it safe to take with NyQuil or DayQuil?
Apr 06, 2023- NyQuil and DayQuil are generally considered safe to take together with Paxlovid because the ingredients in these cold medicines are not significantly affected by the enzyme that Paxlovid inhibits. While Paxlovid does have a minor effect on one enzyme that breaks down dextromethorphan (the cough suppressant in both products), this effect is weak and unlikely to cause clinically significant problems.
Answer
You certainly are correct that Paxlovid (nirmatrelvir; ritonavir tablets) has its fair share of drug interactions but it is generally considered safe to take with both NyQuil and DayQuil
Why Does Paxlovid Have So Many Drug Interactions?
One component of Paxlovid, ritonavir, is a strong CYP3A4 inhibitor, which is an enzyme that plays a crucial role in breaking down many different medications in our body.
A CYP3A4 inhibitor, like ritonavir, can slow down or prevent the action of CYP3A4, which can cause the drugs to stay in our system for longer periods of time than they are supposed to. This can greatly increase the risk of side effects or toxicity.
CYP3A4 is responsible for breaking down around 50% of all drugs on the market, so it's a very important enzyme to consider in regard to potential drug interactions.
NyQuil & DayQuil Information
DayQuil and NyQuil are over-the-counter cold and flu medications that are multi-drug products (i.e., they contain multiple drugs). Both are used to relieve symptoms such as cough, congestion, fever, and sore throat.
DayQuil is typically used during the daytime as it does not cause drowsiness, while NyQuil is intended for nighttime use as it contains ingredients that can help induce sleep.
DayQuil contains:
- Acetaminophen (analgesic)
- Dextromethorphan (cough suppressant)
- Phenylephrine (nasal decongestant)
DayQuil Severe contains all the ingredients in 'original' DayQuil and also adds in the expectorant guaifenesin (the active ingredient in Mucinex).
NyQuil is similar to DayQuil, as it is intended for use as a cough/cold medication. However, it contains a sedating antihistamine to help individuals sleep at night.
NyQuil contains:
- Acetaminophen (analgesic)
- Dextromethorphan (cough suppressant)
- Doxylamine (sedating antihistamine)
NyQuil Severe contains all the ingredients in 'original' NyQuil and also adds in the nasal decongestant phenylephrine.
Paxlovid Is Not Known To Significantly Interact With Any Of The Drugs Contained In DayQuil Or NyQuil
Since the drugs present in NyQuil and DayQuil are not metabolized primarily by CYP3A4, the enzyme inhibited by ritonavir in Paxlovid, there is no known significant interaction expected between the two, and neither of them is known to affect the absorption of the other. They are generally considered safe to take together.
It is important to note that ritonavir (again, a component of Paxlovid), is a minor inhibitor of another enzyme, CYP2D6, which is responsible for metabolizing the cough suppressant in NyQuil & DayQuil, dextromethorphan.
However, most studies note that the inhibition of CYP2D6 is weak, and any alteration to dextromethorphan metabolism is likely to be clinically insignificant. Nevertheless, this is why you may see an interaction come up with an online drug interaction checker.
Final Words
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References & sources
Glossary — Terms in This Answer
- CYP3A4 inhibitor
- A substance that slows down or blocks the enzyme CYP3A4, which normally breaks down medications in your body.
- Ritonavir
- A medication component in Paxlovid that strongly inhibits the CYP3A4 enzyme and can cause drug interactions.
- Nirmatrelvir
- The main antiviral component of Paxlovid used to treat COVID-19.
- Dextromethorphan
- A cough suppressant ingredient found in both DayQuil and NyQuil.
- Expectorant
- A medication ingredient that helps thin mucus to make coughing more productive.
- Antihistamine
- A medication that reduces allergy and cold symptoms by blocking histamine, a chemical in the body.
- CYP2D6
- An enzyme in your body that breaks down certain medications, including dextromethorphan.
- Metabolism
- The process by which your body breaks down medications and other substances so they can be used or eliminated.
Dr. Brian Staiger, PharmD
Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified
Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...
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