Antivenom

Indications

Snake Venom Antiserum is essential for the treatment of venomous bites from the following snakes: Cobra, Common Krait, Russell’s Viper, and Saw-Scaled Viper. The administration is recommended when patients show any of the following clinical signs of envenomation:

Local Envenomation:

• Bite marks present, possibly with blood oozing, blistering, or skin discoloration.
• Rapid or severe swelling of the affected limb (more than 50% of the limb) within a few hours post-bite, even without the use of a tourniquet.
• Swelling of lymph nodes near the bite area within hours of the bite.

Systemic Envenomation:

• Neurotoxic Syndrome: Symptoms of neuro-paralysis, including blurred vision, double vision, difficulty swallowing, drowsiness, head drooping, slurred speech, shallow breathing, ptosis, ataxia, respiratory failure, and generalized flaccid paralysis.
• Hemotoxic Syndrome: Signs of internal bleeding, nausea, vomiting, abdominal pain, tenderness (indicating gastrointestinal or retroperitoneal hemorrhage), kidney damage, or coagulopathy detected by 20-minute whole blood clotting time (WBCT), with or without external bleeding and shock.

Immediate Actions and First Aid

Immediate and effective measures are critical. Never attempt to capture or kill the snake without proper tools and avoid unnecessary exposure to it. Quickly move the patient to a calm, well-ventilated area and limit their movement. Reassure the patient to reduce panic.

First Aid Steps:

• Immobilize the bite area by applying a bandage similar to that used for fractures, keeping the limb below heart level.
• Avoid applying a tourniquet. If one is already in place, loosen it moderately above the bite area to limit venom circulation.
• Ensure the patient receives immediate medical attention at the nearest medical facility.

Always follow the advice of a registered healthcare provider.

Composition

Each vial of Snake Venom Antiserum contains a lyophilized preparation. Upon reconstitution, each milliliter of the antiserum neutralizes the following venom amounts:

• Cobra venom (Naja naja): 0.60 mg
• Common Krait venom (Bungarus caeruleus): 0.45 mg
• Russell’s Viper venom (Vipera russelli): 0.60 mg
• Saw-Scaled Viper venom (Echis carinatus): 0.45 mg

Description

Snake Venom Antiserum is a concentrated, lyophilized serum globulin preparation intended for intravenous administration. It is sourced from hyperimmunized equines and contains equine immunoglobulin fragments F(ab’)2, designed to neutralize venom from the specified snake species. The product also includes cresol, an antimicrobial agent.

Pharmacology

This sterile preparation is composed of antitoxin globulins and derivatives, specifically developed as the most effective antidote for venomous snake bites. It remains the only reliable treatment for snake envenomation.

Dosage & Administration

Snake Venom Antiserum is the only proven antidote for snake envenomation. Timely administration is crucial for neutralizing venom components circulating in the body. Delays in treatment can lead to the need for higher doses and reduced effectiveness.

Recommended Dosage:

• For adult patients: Administer an initial dose of 5-10 vials via slow intravenous infusion. The infusion should be at a rate of 2 mL per minute (undiluted) or 5-10 mL/kg body weight (diluted with Normal or Glucose saline) over one hour.
• For children: The same dosage as adults is recommended.

Monitor the patient closely, particularly during the first hour, to assess vital signs and response to treatment. Further doses may be necessary if coagulopathy persists (confirmed by WBCT) or if symptoms continue or worsen, particularly in cases of respiratory failure from neurotoxic envenomation.

Interaction

Caution should be taken when administering this antivenom to patients using β-adrenergic blockers, as it may exacerbate acute anaphylactic reactions.

Contraindications

There are no known contraindications for the administration of Snake Venom Antiserum.

Side Effects

As the antivenom is derived from equine sources, it may cause allergic reactions. Adverse reactions can range from mild to severe. To minimize risks, ensure the proper dilution and infusion rate of the product. Always keep adrenaline on hand during treatment to manage potential allergic responses.

Pregnancy & Lactation

Despite the risks associated with snake envenomation, pregnancy is not a contraindication for administering Snake Venom Antiserum following a snake bite.

Precautions & Warnings

Special precautions should be followed for patients known to have hypersensitivity to equine-derived products. Some practitioners may recommend premedication with Inj. Adrenaline to reduce the risk of allergic reactions. Avoid intramuscular (IM) injections in patients with hemotoxic bites until coagulopathy is corrected. If a tourniquet is in place, it should be released slowly only after antivenom administration begins.

Therapeutic Class

Vaccines, Anti-sera & Immunoglobulins

Reconstitution

To reconstitute the antivenom, add the diluent into the vial containing the lyophilized preparation. Gently mix by swirling—avoid vigorous shaking. It is recommended that the serum be used immediately after reconstitution.

Storage Conditions

Lyophilized Antivenom remains stable at room temperature. Store in a cool, dark place away from excessive heat. No special storage conditions are required.