Zyrtec - Hydrochlorothiazide Interaction Details
In our latest question and answer, the pharmacist discusses whether or not there is an interaction between Zyrtec and hydrochlorothiazide.
I am taking Hydrochlorothiazide 25 mg for high blood pressure. Can I take Zyrtec 10mg?
Oct 24, 2022- Zyrtec and hydrochlorothiazide are safe to take together with no known drug interactions between them.
- Both medications can cause drowsiness as a side effect, especially when you first start taking hydrochlorothiazide, so be aware of how they affect you.
Answer
Hi and thank you for your great question. I always appreciate it when our readers reach out and ask to double-check that their prescription medications are safe with their OTC drugs.
The good news is that there are no known drug interactions between these two medications in question (Zyrtec and hydrochlorothiazide). They are considered safe to take together. In fact, hydrochlorothiazide is safe with all of the other second-generation antihistamines, including Claritin, Xyzal, and Allegra.
I do want to point out that a small percentage (around 10%) of individuals feel drowsy on Zyrtec. This is a side effect that can sometimes happen with hydrochlorothiazide as well, especially when you first start it, so please be aware of that.
What Is Zyrtec?
Cetirizine (or by the brand Zyrtec) is a “second generation” antihistamine.
It works by binding to histamine receptors in the body so that histamine can’t bind to them. This helps to reduce the symptoms typically caused by allergies such as a runny nose, watery eyes and sneezing. It is generally well tolerated and lasts about 24 hours although, as mentioned, it can cause drowsiness.
What Is Hydrochlorothiazide?
Hydrochlorothiazide, or HCTZ, is a 'thiazide' diuretic medication that’s commonly used to treat high blood pressure and swelling due to fluid buildup. It’s a very inexpensive and a common first-line therapy to treat high blood pressure and related cardiac conditions.
Final Words
Thanks for reaching out to us and I hope this helps.
Glossary — Terms in This Answer
- Drug interactions
- When two medications affect each other's effectiveness or safety when taken together.
- OTC drugs
- Over-the-counter medications that you can buy without a prescription.
- Second-generation antihistamine
- A newer type of allergy medication that blocks histamine and typically causes less drowsiness than older antihistamines.
- Side effect
- An unintended reaction to a medication in addition to its main therapeutic effect.
- Histamine receptors
- Binding sites on cells where histamine attaches and triggers allergic symptoms.
- Thiazide diuretic
- A type of medication that helps remove excess fluid from the body by increasing urination.
- First-line therapy
- The initial or preferred treatment option that doctors typically try first for a condition.
- Cardiac conditions
- Medical disorders or diseases that affect the heart and its function.
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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