From the Guidelines
Antivenin (antivenom) should be administered for viper bites when there are signs of envenomation, including progressive local tissue effects, systemic symptoms, or laboratory abnormalities, as indicated by expert consensus guidelines 1. The decision to administer antivenin is based on the presence of specific clinical indications, such as significant swelling, ecchymosis, or pain extending beyond the bite site, as well as systemic symptoms like hypotension, altered mental status, or vomiting, and laboratory abnormalities like coagulopathy, thrombocytopenia, or elevated creatine kinase 1.
- Key considerations for antivenin administration include:
- Geographic region and snake species
- Severity of envenomation symptoms
- Patient's overall health and medical history
- Availability of antivenin and hospital resources The specific antivenin used depends on the geographic region and snake species; in North America, CroFab or Anavip are commonly used for pit viper envenomations, with dosing typically starting with 4-6 vials given intravenously, and additional vials administered until initial control of symptoms is achieved, as recommended by expert guidelines 1.
- Important aspects of antivenin therapy include:
- Early administration, ideally within 6 hours of the bite
- Close monitoring in a hospital setting for signs of anaphylaxis or serum sickness
- Supportive care, including wound care, tetanus prophylaxis, and pain management
- Consideration of the patient's individual needs and medical history when determining the appropriate course of treatment.
From the Research
Indications for Snakebite Antivenin Viper
The indications for administering snakebite antivenin (antivenom) for viper bites are as follows:
- Presence of progressive venom injury, defined as worsening local injury (e.g., swelling, ecchymosis) 2
- Clinically important coagulation abnormality 2
- Systemic effects (e.g., hypotension, altered mental status) 2
- Severe local envenomation, such as extensive swelling and tissue necrosis 3
- Moderate to severe local signs, including rapidly progressing edema 4
- Systemic signs, such as tachycardia, vomiting, abdominal pain, and hypotension 4
Administration of Antivenom
The administration of antivenom is based on the severity of the clinical syndrome, with the following considerations:
- A fixed dose regimen of 50 ml of antivenom may not always be sufficient, and repeated doses may be necessary 5
- Antivenom treatment based on systemic symptoms can be effective and may require less antivenom than a fixed dose regimen 6
- The use of polyvalent antivenom, such as the Indian (Haffkine) polyvalent antivenom, may be effective in treating envenomation by the shore pit viper, although further studies are needed to confirm this 3
- In children, a 50 ml dosing of V. palaestinae antivenom is efficacious and safe for the treatment of systemic and progressive local manifestations of envenomation by V. palaestinae 4