Doxycyline hydrochloride Doxycycline hyclate is a synthetic tetracycline derivative with similar antimicrobial activity.   Drug Indication  1)Treatment of periodontal disease in dogs   2)Pigs: clinical signs with porcine respiratory disease. Chickens: to reduce mortality, morbidity, and clinical signs and to reduce lesions due to Pasteurellosis. Also in respiratory infections caused by Ornithobacterium rhinotracheale.   3)Treatment of infections of the respiratory tract and alimentary tract caused by micro-organisms susceptible to doxycycline.   4)Chickens: to reduce mortality, morbidity, and clinical signs and to reduce lesions due to Pasteurellosis caused by Pasteurella multocida or to reduce morbidity and lesions in respiratory infections caused by Ornithobacterium rhinotracheale (ORT)   5)Treatment of systemic amyloidosis caused by beta-2 microglobulin   6)Treatment of familial amyloid polyneuropathy