Holly F asked
Does Zyrtec make you sleepy?
Answer
Yes, Zyrtec (cetirizine) can cause you to feel sleepy and can create a general feeling of drowsiness and sedation. Below, we discuss Zyrtec in detail as well as the incidence of sedative side effects.
Zyrtec (Cetirizine) Classification
Zyrtec (cetirizine) is classified as a "second-generation" antihistamine. There are currently four second-generation antihistamines available over the counter (OTC) in the United States:
- Zyrtec (cetirizine)
- Claritin (loratadine)
- Allegra (fexofenadine)
- Xyzal (levocetirizine)
Second-generation antihistamines offer significant benefit over first generation antihistamines, such as Benadryl in that they last about 24 hours per dose and are typically non-drowsy. Unfortunately, Zyrtec (cetirizine) is the only second-generation antihistamine that is known to cause significant sedation in individuals. For this reason, it is not marketed as "non-drowsy" as other products such as Claritin and Allegra are.
Most studies find that Zyrtec causes sedation at a much higher rate than other second-generation antihistamines. The actual incidence of drowsiness among individuals taking Zyrtec isn't fully known but is reported to be around 5-15%.
Zyrtec And Drowsiness Side Effects
More specifically, clinical trial data for Zyrtec indicated the following incidence rates for drowsiness and related effects:
- Drowsiness (14.3%)
- Fatigue (3.4%)
- Dizziness (2%)
Fatigue and drowsiness are dose-related, meaning higher doses are more likely to cause side effects. For example, the incidence of drowsiness was 11% in those taking Zyrtec 5 mg. In those taking Zyrtec at the 10 mg dose, the incidence rate increased to 14%.
Although Zyrtec is associated with higher rates of drowsiness than other second-generation antihistamines, it may be the most effective medication for certain types of allergies. Many studies put Zyrtec as the most effective second-generation antihistamine for the treatment of wheal and flare reactions (i.e. skin reaction to an allergen producing hives, swelling and inflammation).
To conclude, it is important to understand that Zyrtec may make you sleepy, but effects vary by individual.
