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What are the side effects of zyrtec, (cetirizine) if any?
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Dr. Steven Machtinger
Internal Medicine - Allergy & Immunology
In brief: Sleepiness
The major side-effect of zyrtec (cetirizine) is sedation - sleepiness, fatigue, and slowed reaction time.
This occurs in 1 out of 10 or 1 out of 12 users. Compare to Benadryl (diphenhydramine) 1 of 3 users or clariting 1 in 50 users. Also occasionally reported are stomachache, headache, diarrhea, constipation & dry mouth & throat. In older men zyrtec can sometimes cause difficulty with urination.

In brief: Sleepiness
The major side-effect of zyrtec (cetirizine) is sedation - sleepiness, fatigue, and slowed reaction time.
This occurs in 1 out of 10 or 1 out of 12 users. Compare to Benadryl (diphenhydramine) 1 of 3 users or clariting 1 in 50 users. Also occasionally reported are stomachache, headache, diarrhea, constipation & dry mouth & throat. In older men zyrtec can sometimes cause difficulty with urination.
Dr. Steven Machtinger
Dr. Steven Machtinger
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