Benadryl
is safe to use in dogs, and the dose
is approx. 1mg/lb every 8-12 hours; I have used 25mg twice daily in pets slightly under 20# with no ill effects. In approx 10% of dogs, any antihistamine can unexpectedly cause excessive sleepiness, or paradoxical excitment, and if these symptoms occur, then the antihistamine is discontinued. Perhaps this happened to one of the prior rescue dogs when given benadryl.