Can I Give My Cat Zyrtec?

Yes, with care
Cetirizine is commonly referenced for cats at published doses. Published guidance for cats: 5 mg per cat, every 24h. One of the better-tolerated antihistamines in cats.
Source: Veterinary Partner (VIN)
Get the exact range for your cat's weight

Skip it or ask a vet first if

Zyrtec-D / decongestant versionskidney disease

The safe habit

Confirm any medication decision with your veterinarian, who knows your cat's health history and other medications. VetDose shows published reference data, not prescriptions.