engleski

Insight in differences in venom and antivenom pharmacokinetics in sera of V. ammodytes bitten patients treated by currently available therapies

Due to current shortage in Zagreb antivenom availability, in Slovenia V. ammodytes venomous bites have recently been treated with antivenoms of French and UK producers. In Croatia, for therapeutic purposes the remaining doses of Zagreb antivenom have still been used. Composition differences between these three antivenoms exist. First, they differ slightly in specificity. Zagreb antivenom has been raised against V. a. ammodytes venom, but is clinically effective and used against all European venomous snakes (V. ammodytes, V. berus, V. aspis, V. lebetina and V. xanthina). Viperfav from the French producer has been raised against the mixture of V. aspis, V. berus and V. ammodytes venoms, but was mostly used against V. aspis and V. berus. ViperaTAb from the UK has been raised against V. berus venom solely, and used so far only to treat envenomations caused by V. berus. Second, they differ in type of the active drug component. Namely, Zagreb antivenom and Viperfav are F(ab')2-based preparations, while ViperaTAb is formulated of Fab fragments. And third, investigated antivenoms have differently prescribed administration routes - intravenous for ViperaTAb and Viperfav or intramuscular for Zagreb antivenom. Since ViperaTAb’s and Viperfav’s therapeutical suitability for use against V. ammodytes venom-induced toxicity lately has been reported as poorer in comparison to that of Zagreb antivenom, we aimed for elucidation of their distinct clinical efficiency. In serum samples of V. ammodytes-envenomed and treated patients, collected during the few days long hospitalization, concentrations of venom, neurotoxic ammodytoxins and F(ab’)2 or Fab fragments were determined. Differences in pharmokinetic profiles of investigated antivenoms were revealed. Antivenom level in circulation was highly dependent on the active principle type and route of administration, significantly affecting venom systemic clearance and consequently, clinical status of the patient. Overall, the treatment of patients with Zagreb antivenom did not required additional doses, in contrast to particularly ViperaTAb treatment. This effect might be due to higher specificity of Zagreb antivenom for V. ammodytes venom, but also due to differences in administration route and antivenom pharmacokinetics.

Antivenom ; Venom ; Pharmacokinetics

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