Published dose range
The published veterinary reference range for diphenhydramine in cats is 1-2 mg per kg of body weight, given every 8-12h. In practice: 2-4 mg total per cat.
Source: Merck Veterinary Manual →Published range by weight
| Weight | Diphenhydramine (published range) |
|---|---|
| 6 lb cat | 2.7-5.4 mg |
| 8 lb cat | 3.6-7.3 mg |
| 10 lb cat | 4.5-9.1 mg |
| 12 lb cat | 5.4-11 mg |
| 15 lb cat | 6.8-14 mg |
Computed from the published 1-2 mg/kg reference range, every 8-12h. Product strengths rarely split evenly, so round DOWN to the nearest practical dose and confirm with your vet.
Bitter; cats foam/drool at the taste. Paradoxical excitement possible.
Skip it or ask a vet first if
glaucomaurinary obstructionwith sedativescombination cold products
If you think you overdosed
Call the Pet Poison Helpline: 855-764-7661 or ASPCA Poison Control: 888-426-4435. Both are staffed 24/7 by veterinary toxicologists.