Some vets suggest using an over-the-counter cough medicine that has dextromethorphan in it for dogs that have a chronic, dry cough, according to Doctors Foster and Smith. A veterinarian should be consulted before giving the dog an over-the-counter cough medicine, because some medicine has ingredients that may harm your dog.
Though the Food and Drug Administration does not approve of using over-the-counter cough medicine for dogs, dextromethorphan has proven effective at suppressing the cough center in a dog's brain, according to Doctors Foster and Smith. Vets do not recommend using an over-the-counter cough medicine for dogs that have a productive cough. Vets also warn against using over-the-counter cough medicine that contains additives like acetaminophen or caffeine. The dog's vet should be informed if the dog becomes nauseous, dizzy, drowsy or seems otherwise negatively affected by the medicine.