U.S. doctors online nowAsk doctors free
RO
A 17-year-old female asked:

My body acts weird. everytime i use zyrtec (cetirizine) drops i get very little drowsy only on the first dose. my tolerance goes away if i stop it for long. why?

1 doctor answer1 doctor weighed in
Dr. John Chiu
Allergy and Immunology 57 years experience
Expected: That's true with most sedating antihistamines. One does get used to the drowsiness after a couple of weeks. Whether this is due to a faster breakdown of the drug by the liver or reconditioning of the brain- no one knows However it is believed that some impairment in performance does happen when measured by performance tools even though you may not be feeling it.

90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more. Get help now:

Ask doctors free
Educational text
Free
Talk to a doctor
24/7 visits - just $39!
50% off with $15/month membership

90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more. Get help now:

Ask doctors free
Educational text
Free
Talk to a doctor
24/7 visits - just $39!
50% off with $15/month membership
Last updated Nov 14, 2020

Disclaimer:

Content on HealthTap (including answers) should not be used for medical advice, diagnosis, or treatment, and interactions on HealthTap do not create a doctor-patient relationship. Never disregard or delay professional medical advice in person because of anything on HealthTap. Call your doctor or 911 if you think you may have a medical emergency.