Hi,
Thanks for posting your query. I am happy to address your questions, zyrtec-d common side-effects are drowsiness, dizziness, tiredness, dry mouth, nausea, headache, or trouble sleeping may occur. If any of these effects persist or worsen, tell your doctor promptly. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including fast/irregular/pounding heartbeat, shaking (tremor), mental/mood changes (such as anxiety,
nervousness,
restlessness). A very serious
allergic reaction to this drug is rare. However, get
medical help right away if you notice any symptoms of a serious allergic reaction, including rash, itching/swelling (especially of the face/tongue/throat),
severe dizziness, trouble breathing. Altered smell (dysosmia) could be related to your respiratory infection. Hope I have answered your query. If you have any further questions, I will be happy to help. Thanks