Hexavalent Snake Antivenom Immunoglobulins
Type and form of product:
Purified immunoglobulin, injectable liquid
This product is made from purifying and condensing of Hyperimmune horse plasma against 6 types of snakes’ venom as follows:
- Vipera lebetina
- Vipera albicornuta
- Echis carinatus
- Pseudocerastes persicus
- Agkistrodom halys
- Naja naja oxiana
The active ingredients of this product include the fragment of immunoglobulins’ F(ab′)2. Each milliliter has the ability to neutralize more than 50 LD50 of the venom of each of the mentioned snakes based on its lethal property on the mice.
This product contains up to 0.25% phenol as a preservative.
For neutralizing the snakes’ venom mentioned above.
Administration route and dosage:
Since the amount of received venom among the bitten children or adults is the same, they should be taken the same amount of antivenom, regardless of their ages and heights. However, children and weak people are at high risk. Considering the severity of the symptoms and clinical complications of the bitten person, it is usually recommended to administer 1 to 2 ampoules via intravenous infusion, as an initial dose, to neutralize the venom. In severe cases, especially if there is a delay in treatment, administration of more ampoules will be required. This amount depends on the results of the tests and the clinical examination and is prescribed by the physician.
In case of persistence or recurrence of bleeding, as well as the persistence or worsening of neurological and cardiovascular symptoms: repeat the initial dose after 1-2 hours.
In case of persistence or reversal of coagulation problems: Repeat the initial dose after 6 hours
Appropriate time and how to use:
This product should be prescribed immediately after the snake bite via intravenous infusion (It should be diluted with 250-500 ml of 9% saline or 5% glucose solution. Infusion speed should be 250 ml/hr). If there is no necessary facility for infusion, antivenom could be injected intravenously by using of a syringe and the rate of 2 ml/min, under supervision of a physician.
How to use during pregnancy and lactation:
There is no information about Undesirable effect of this product during pregnancy and lactation.
- This product cannot be used in cases of scorpion sting.
- Do not use the antivenom if you notice changes in color, opacity and particles in the ampoule.
- Don’t use the antivenom after the expiry date.
Due to the fact that this product is made from horse plasma derivatives and is a heterologous agent for humans, it is possible to observe the following side effects:
- Early side effects (anaphylactic) that usually occur 10 - 180 minutes after injection/ infusion including dry coughs, shortness of breath, heaves, itching, vomiting, nausea, colic, diarrhea, hypotension, tachycardia, and anaphylactic shock.
- Delayed side effects (caused by endotoxins) that usually occur 1 - 2 hours after injection/ infusion, including seizure, shaking chills, fever, vasodilation and hypotension.
- Late side effects (serum sickness) that usually occur 1 - 12 days for an average of 7 days after injection/ infusion, including fever, nausea, vomiting, diarrhea, itching, rashes or heaves, muscular pain, joint pain, lymphadenopathy, proteinuria together with nephritis, mononeuritis multiplex, and in rare cases; encephalopathy.
Note: Individuals who receive antihistamine or corticosteroid are less likely to face with late side effects.
Therapeutic measures in case of occurrence of anaphylactic shock:
- Stop the injection/infusion of antivenom as soon as noticing signs of anaphylactic shock.
- Inject 0.5-1 ml of adrenaline (1mg/ml) in adults and 0.01 mg/kg in children intramuscularly, and if necessary repeat it every 5-10 minutes, until desirable hemodynamic condition is achieved.
- In case of intensification of anaphylactic reactions, inject the adrenaline intravenously.
- Prescribe the antihistamine and corticosteroid as complementary treatment.
- Prescribe the oxygen and if necessary give artificial respiration.
- Do Infusion of liquids to compensate for hypotension.
- Despite symptom healing of anaphylactic shock, continue prescription of antivenom.
There has been not a comprehensive study about the drug interactions of this product yet.
Precautions and warnings:
- Before injection/infusion of the antivenom, prepare 1 ml of adrenaline (1mg/ml) in a syringe and keep it available.
- In individuals with history of severe atopic diseases, if systematic signs of snakebite exist, prescription of adrenaline, H1&H2 blockers, corticosteroids, and salbutamol, before injection/infusion of antivenom, may prevent the occurrence of bronchospasm.
- In case of any reactions during prescription of antivenom, its injection/infusion should be stopped immediately, and if reactions continue (despite the stopping of injection), symptomatic treatment should be began.
- Do not use frozen antivenom.
- Follow the aseptic condition when inject/infusion the antivenom.
- Notice the possibility of getting tetanus and microbial infection as a result of the snakebite so take necessary measures.
- Prescription of sedatives such as acetaminophen, is recommended, but avoid drinking alcoholic beverages or morphine.
- Keep the injured body warm before and after the prescription of antivenom, and take him under supervision for 2 hours after injection.
- Decrease the anxiety and excitement of the injured person.
- Keep the injured organ fixed, as much as possible.
- Do not use the tourniquet especially in case of edema.
- To prevent the edema, it is recommended to tie a wide band above the bite area, so that it doesn’t block the blood flow.
- Do not reuse the remaining of antivenom.
- Do not manipulate, cut, or suck the bite area.
Safe disposal of waste or partially used ampoules:
Empty or partially used ampoules must be properly sterilized by autoclaving, burning or appropriate chemicals.
Keep the antivenom at 2 to 8 °C away from light. In this condition, it can be used up to the expiry date stated on the product label.
This product is provided in single box, containing 10 milliliters ampule.
1-David A. Warrel, 2010, guidelines for the management of snake-bites, world health organization- regional office for south-east Asia.
2- WHO Expert Committee on Biological Standardization, 2017, Guidelines for the production, control and regulation of snake antivenom immunoglobulins, TRS, No. 1004, annex 5