Taking Zyrtec With NyQuil
In our latest question and answer, the pharmacist discusses whether or not Zyrtec (cetirizine) can be taken with NyQuil.
Can I take my Zyrtec along with taking Nyquil?
Mar 30, 2022- Zyrtec and NyQuil can be taken the same day but should be separated by at least a few hours to avoid increased drowsiness and sedation.
- Both medications contain antihistamines that can cause drowsiness, so taking them together increases the risk of side effects like sedation, dry mouth, and dry eyes.
- If you take Zyrtec in the morning when you tolerate it well, you can safely take NyQuil in the evening.
Thank you for your question!
In most cases, it is safe to take Zyrtec (cetirizine) the same day as taking NyQuil.
However, they generally should not be taken at the same time, or, at least should be separated from one another by at least a few hours to lessen the possibility of excess sedation and drowsiness.
More Info On NyQuil - Zyrtec Interaction
Zyrtec (cetirizine) is a "second generation" antihistamine that is an effective all-day (i.e. 24 hour) allergy medication.
While most second-generation antihistamines do not cause drowsiness or sedation (e.g. Claritin), Zyrtec is not considered non-drowsy. In fact, clinical studies for Zyrtec have reported that about 13% of users will experience sedation.
NyQuil is a combination ingredient cough/cold medication and contains the following active ingredients:
- Acetaminophen (analgesic)
- Dextromethorphan (cough suppressant)
- Doxylamine (sedating antihistamine)
Doxylamine, like Zyrtec, is an antihistamine, although it is considered "first generation". First-generation antihistamines are characterized by their relatively short duration of action (~4 to 6 hours) and by the sedation they cause.
While doxylamine is effective for the treatment of allergy symptoms, it is most often used in over-the-counter products as a sleep aid due to the sedation it causes.
The concern with using NyQuil and Zyrtec at the same time is the potential for additive side effects from each, which could include:
- Drowsiness
- Dry mouth
- Dry eyes
- Sedation
This interaction, for most people, wouldn't be considered too serious, but it is a drug interaction nonetheless, so is important to be aware of.
Final Words
Overall, Zyrtec should not be taken at the same time as NyQuil due to the additive sedative effects, as described in the section above.
However, if you take Zyrtec in the morning and tolerate it well, you can certainly take NyQuil in the evening with no ill effects.
References & sources
Glossary — Terms in This Answer
- Antihistamine
- A medication that blocks the effects of histamine, a chemical in the body that causes allergy symptoms like itching and sneezing.
- Cetirizine
- The active ingredient in Zyrtec, a type of antihistamine used to treat allergy symptoms.
- Sedation
- A state of reduced alertness or drowsiness caused by medication.
- Second generation antihistamine
- A newer type of antihistamine designed to be less likely to cause drowsiness than older versions.
- First generation antihistamine
- An older type of antihistamine that typically causes drowsiness as a side effect.
- Dextromethorphan
- An active ingredient in cough medicines that works to suppress or reduce coughing.
- Doxylamine
- A sedating antihistamine found in NyQuil that helps with allergy symptoms and also promotes sleep.
- Additive side effects
- When two medications combine to increase unwanted effects more than either drug would cause alone.
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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