VetInfo states that while cough medicines for humans are occasionally given to dogs, medicines prescribed for the dog are best. Cough medicines that contain dextromethorpan are best used as a cough suppressant for dogs, according to VetInfo, and medicines with aspirin or acetaminophen are extremely dangerous.
VetInfo states that medication overdose is the top cause of death in pets. The safest dosage is 0.5 to 1 milliliter for every pound of the dog’s weight. Cough syrup should not be given to a dog that has a wet cough, according to VetInfo; expulsion of mucus is necessary for the dog to heal. Cough medicines should not be used in combination with caffeine or acetaminophen.