We do not use this drug in dogs, so ideally I recommend that you induce vomiting if he ingested this less than 3 hours ago.I would give him 1 Tablespoon of 3% hydrogen peroxide per 10 pounds of body weight (no more than 3 tablespoons even if he is more than 35 pounds) orally, mixed with bread chunks or a little ice cream.Then get him running around to get the peroxide bubbling so he vomits.If no vomiting in 10 minutes repeat the peroxide dose.Symptoms of toxicity of these types of drugs in dogs can include agitation, depression, aggression, vocalization, seizures
, lack of coordination, tense muscles
, muscle tremors or spasms, change in heart rate, increase in blood pressure, elevated body temperature and diarrhea. The more they ingest the more serious the toxicity.If we cannot get him to vomit the pill the safest thing would be to see a veterinarian to have activated charcoal administered, fluids given and observation and treatment of other symptoms as they occur.But since he's a good sized English Bulldog
(at least 50 pounds) then odds are 20mgs won't cause serious symptoms for most dogs.You are likely to see incoordination and sleepiness, maybe stomach
upset, but not the more serious effects we see with higher doses, like muscle tremors or seizures, or changes in blood pressure.If you choose you can elect to observe him and have him examined if you see tremors or an elevated heart rate..I would expect him to sleep away the effects of this dose, unless he is very, very sensitive.Keep him away from stairs.