Dogs who are jumpy -- quick to snap, growl or bite when startled or confronted -- may have a condition known as fear aggression. Clomipramine is a tricyclic antidepressant drug. It is approved for dogs to help maintain adequate levels of seratonin in their brains. Adequate seratonin levels allow the dog to remain calm enough to be receptive to learning more suitable behavior.
Effect of Medication Alone
A study by the Veterinary Medical Teaching Hospital in California concluded that aggression levels decreased at similar levels in dogs given clomipramine and those given a placebo when there was no behavioral modification conducted during the time of the study. This means that the medication is not a magic bullet to change your dog's behavior. Although he will become less reactive after several weeks on the medication, you will need to provide training to help him cope with scary situations in a less aggressive manner.