AZT IN THE TREATMENT OF FELINE IMMUNODEFICIENCY VIRUS-INFECTION .1.

AZT (3'-azido-2',3'-dideoxythymidine, zidovudine, Retrovir,(R) Burroug hs Wellcome Co., Research Triangle Park, NC) is the only compound avai lable for the causative treatment of FIV infection in veterinary pract ice. To determine the efficacy of AZT against FIV infection an in vitr o study to show antiviral activity and cytotoxicity in cell cultures, followed by pharmacokinetic investigations to evaluate the optimum dos age for in vivo trials and to monitor side effects were performed. Fin ally, three different in vivo studies in FIV infected cats were perfor med to determine the efficacy of AZT and its applicability in veterina ry practice. AZT was able to reduce virus replication in vitro and in vivo. It improved the immunological and clinical status of FIV infecte d cats, increased the quality of life, and prolonged life expectancy. AZT should be used either subcutaneously or orally in a dosage of 5 mg /kg bodyweight every 12 hours. For subcutaneous application it is reco mmended to dilute the lyophilisate in a 5-mL isotonic sodium chloride solution. In oral application AZT is administered in gelatin capsules specially prepared for the corresponding bodyweight of the cat. During treatment, evaluation of laboratory values is recommended on a regula r basis.