Amitriptyline HCL: Clinical Study for the Treatment of Feather Picking
Presenting Author: Chris T. Eugenio, DVM
Animal Clinic and Hospital, Moscow, ID
Interpretive Review and comments by Dr. Nemetz:
There are numerous etiologies to the phenotypic (visible) symptoms of feather damaging behavior. But, if the etiology is ruled out to a psychological basis then several antidepressants have been used with moderate success in avian medicine. Dr. Eugenio presented a clinic trial using but one other tricyclic antidepressant drug: Amitriptyline HCL.
As a tricyclic antidepressant, Amitriptyline HCL has anticholinergic (blocks acetylcholine at parasympathetic nerve endings), antihistamine and local anesthetic properties. With these properties it has been used for anxiety in dogs, excessive grooming and urine spraying in cats, as well as antipruritic properties. Side affects include sedation, dry mouth, urine retention, constipation, tachycardia, disorientation, and hyperactivity which are all the functions the parasympathetic nervous system helps to control in the body. This drug must be used carefully in patients with hyperthyroid disease, diabetes mellitus, and liver or kidney disease. It is also synergistic with other CNS depressants and cimetidine thereby compounding their effects.
Dr. Eugenio used Amitriptyline HCL at 2mg/kg PO q24hr in 11 feather picking birds: 2 African greys, 1 sulfur-crested cockatoo, 1 umbrella cockatoo, 3 grey-cheeked parakeets, 1 mitred conure, 1 quaker parakeet, 1 grey cockatiel, and 1 redheaded Amazon. This was attempted after a thorough medical workup was performed first to rule out any systemic disease process.
Response, if any, occurred 1-2 weeks after initiation of therapy. The African grey, conure, cockatiel, and grey-cheeked parakeet had some improvement or total resolution of picking symptoms. The cockatoos and Amazon showed no improvements.
Dr. Nemetz has tried this drug since this presentation on a Jardine parrot. The results were not satisfying similar to the cockatoos in Dr. Eugenio's study. However if these drugs are not tried, some birds may have no hope at a more comfortable life.