LONG-TERM TREATMENT OF DISEASED, FIV-SEROPOSITIVE FIELD CATS WITH AZIDOTHYMIDINE (AZT)

The long-term effectiveness of Azidothymidine (AZT, Zidovudine) was evaluated in FIV-seropositive cats with clinical symptoms (n = 9; Group 1) compared with conventional symptomatical therapy (n = 5; Group 2). The oral administration of Azidothymidine at a dosage of 5 mg/kg BW yielded a mean peak plasma concentration of 4.59 mu M one hour after application (median: 3.74 mu M). Elimination half time was 1.5 h. The permanent oral application of Azidothymidine at a dosage of 5 mg/kg BW TID led to a total recovery from clinical symptoms in six of nine FIV-seropositive cats (Group 1) 4-6 weeks after the onset of therapy. One cat clinically improved with only sporadical recurrence of disease; therapy with Azidothymidine was not effective in two cats. All the FIV-seropositive cats treated symptomatically responded well to antibiotics and immunomodulators within 10-14 days (n = 5; Group 2). Recurrence of clinical symptoms was noticed in three of five patients within 2 years after therapy and one cat died. During the treatment with Azidothymidine hyperproteinemia and abnormal albumin-to-globulin ratio became normal within 6 months in four FIV positive cats (Group 1), whereas hyperproteinemia did not change in Group 2. The following adverse effects were noticed in Group 1: a transient decrease of red blood cell count (RBC), packed cell volume (PCV) and haemoglobin until the 4th week of application of Azidothymidine (5/8), but the haemogram was within the normal range after 3 months. In one cat with hyperglycemia the anaemia remained until the administration of Azidothymidine was terminated. Heinz (Schmauch) bodies in the erythrocytes appeared in two FIV-positive cats 2 weeks after the onset of the therapy.