Evaluation of antivenom therapy in Vipera palaestinae bites

Background: Vipera palaestinae antivenom has been successfully used to treat systemic and progressive local manifestations inflicted by this snake. The clinical course of several envenomations created the impression that the recommended fixed dose regimen of antivenom (50 ml) may not always be sufficient. Objective: To evaluate the V. palaestinae antivenom fixed dose regimen and to assess the need for repeated antivenom administration as well as possible adverse effects. Methods: Retrospective review of prospectively collected poison center data over a one-year period. Results: One hundred and twelve patients were evaluated, 48% of whom were treated with antivenom. Antivenom treatment resulted in complete disappearance of systemic manifestations with no relapse. Three patients required additional doses of antivenom for marked progressive local signs—one initially received 50 ml of antivenom and two others only 30 ml. Anaphylaxis and serum sickness were each observed in 3.7% of the treated patients. Conclusion: The fixed dose regimen of 50 ml V. palaestinae antivenom is efficacious for the treatment of systemic and progressive local manifestations caused by this snake. There is insufficient data on whether smaller doses can be successfully used for systemic manifestations and whether initial larger doses are justified for marked progressive local signs (e.g. involvement of an entire limb). Randomized prospective controlled studies are needed to elucidate these issues.