Can I Give My Dog Tagamet?

Yes, with care
Cimetidine is commonly referenced for dogs at published doses. The published veterinary reference range for cimetidine in dogs is 5-10 mg per kg of body weight, given every 8-12h. Older antacid; famotidine usually preferred (fewer drug interactions).
Source: Merck Veterinary Manual
Get the exact range for your dog's weight

Skip it or ask a vet first if

many drug interactionskidney disease

The safe habit

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