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Comparison of platelet count recovery with use of vincristine and prednisone or prednisone alone for treatment for severe immune-mediated thrombocytopenia in dogs

Elizabeth A. Rozanski DVM, DACVECC, DACVIM1,2, Mary Beth Callan VMD, DACVIM3, Dez Hughes BVSc, DACVECC4,5, Nancy Sanders DVM, DACVIM, DACVECC6,7, and Urs Giger Dr med vet, DACVIM8
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  • 1 Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104- 6010.
  • | 2 Department of Clinical Sciences, School of Veterinary Medicine, Tufts University, North Grafton, MA 01536.
  • | 3 Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104- 6010.
  • | 4 Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104- 6010.
  • | 5 Present address is the Royal Veterinary College, University of London, London, England.
  • | 6 Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104- 6010.
  • | 7 Present address is Veterinary Referral Centre, 48 Notch Rd, Little Falls, NJ 07424.
  • | 8 Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104- 6010.

Abstract

Objective—To evaluate the effect of prednisone alone, compared with a combination of prednisone and vincristine, on platelet counts in bleeding dogs with severe primary immune-mediated thrombocytopenia (IMT).

Design—Prospective case study.

Animals—24 dogs with severe primary IMT.

Procedure—All dogs received immunosuppressive doses of prednisone (1.5 to 2 mg/kg [0.7 to 0.9 mg/lb] of body weight, PO, q 12 h). In addition, 12 dogs received a single dose of vincristine (0.02 mg/kg [0.01 mg/lb], IV). Platelet count, transfusion requirement, and outcome were monitored. A response was defined as an increase in platelet count to ≥ 40,000/µl. Dogs in the prednisone group that failed to respond received 1 dose of vincristine on day 7.

Results—Dogs that received prednisone and vincristine had a significantly faster increase in platelet count to ≥ 40,000/µl than dogs that received prednisone alone (mean ± SD, 4.9 ± 1.1 vs 6.8 ± 4.5 days, respectively). A similarly rapid response was observed in dogs that received vincristine on day 7 after treatment with prednisone alone failed. Furthermore, duration of hospitalization was reduced in the vincristine group, compared with the prednisone group (5.4 ± 0.3 vs 7.3 ± 0.5 days, respectively). No adverse effects attributable to vincristine were observed in any dog.

Conclusions and Clinical Relevance—Administration of combined vincristine and prednisone is associated with more rapid increase in platelet numbers and shortened duration of hospitalization in dogs with IMT, compared with use of prednisone alone. Early use of vincristine seems warranted in dogs with severe primary IMT. (J Am Vet Med Assoc 2002; 220:477–481)

Abstract

Objective—To evaluate the effect of prednisone alone, compared with a combination of prednisone and vincristine, on platelet counts in bleeding dogs with severe primary immune-mediated thrombocytopenia (IMT).

Design—Prospective case study.

Animals—24 dogs with severe primary IMT.

Procedure—All dogs received immunosuppressive doses of prednisone (1.5 to 2 mg/kg [0.7 to 0.9 mg/lb] of body weight, PO, q 12 h). In addition, 12 dogs received a single dose of vincristine (0.02 mg/kg [0.01 mg/lb], IV). Platelet count, transfusion requirement, and outcome were monitored. A response was defined as an increase in platelet count to ≥ 40,000/µl. Dogs in the prednisone group that failed to respond received 1 dose of vincristine on day 7.

Results—Dogs that received prednisone and vincristine had a significantly faster increase in platelet count to ≥ 40,000/µl than dogs that received prednisone alone (mean ± SD, 4.9 ± 1.1 vs 6.8 ± 4.5 days, respectively). A similarly rapid response was observed in dogs that received vincristine on day 7 after treatment with prednisone alone failed. Furthermore, duration of hospitalization was reduced in the vincristine group, compared with the prednisone group (5.4 ± 0.3 vs 7.3 ± 0.5 days, respectively). No adverse effects attributable to vincristine were observed in any dog.

Conclusions and Clinical Relevance—Administration of combined vincristine and prednisone is associated with more rapid increase in platelet numbers and shortened duration of hospitalization in dogs with IMT, compared with use of prednisone alone. Early use of vincristine seems warranted in dogs with severe primary IMT. (J Am Vet Med Assoc 2002; 220:477–481)