While most people do not experience side effects while taking Zyrtec, problems could occur. Some of the most common side effects that were seen in adults during clinical studies include dry mouth, drowsiness, and fatigue. The most common side effects in children include
sore throat,
headache, and abdominal pain.
When side effects do occur, they are often minor and either do not require medical attention or can be treated easily. However, serious Zyrtec problems could occur. Potentially serious side effects that should be reported to your healthcare provider immediately include wheezing or other breathing problems, difficulty passing urine, and a rapid heart rate.
(Click Zyrtec Side Effects to learn more about possible side effects of this medicine, including a more complete list of common problems, as well as rare but potentially serious problems that require medical attention.)