Anti-Snake Venom
Synonyms :
ASV, Snake Antivenom Serum
Mechanism :
Snake venoms are complex mixtures of enzymatic proteins and different toxins. In terms of their effects, however, they may be broadly categorized as hemotoxic or neurotoxic. They may also contain agents that promote or prevent blood clotting. Among snakes, cobras and coral snakes may be singled out as having particularly neurotoxic venom.
Indication :
Contraindications :
Before injection of Anti-Snake Venom Serum, history of prior injections of serum (e.g. anti-tetanus or anti-diphtheria serum), personal or familial history of allergy, i.e. asthma, eczema or drug allergy should be elucidated.
The sensitivity of the patient to Anti-Snake Venom Serum is tested by injecting subcutaneously 0.1 ml of this serum diluted 1:10. The patient should be observed for 30 minutes for local and general reactions. If the test dose shows either local reaction such as flare or general anaphylactic reaction such as pallor, sweating, nausea, vomiting, urticaria, and fall of blood pressure, these should be countered immediately by intramuscular injection of 1 ml of 1:1000. Adrenaline and with corticosteroids which should be always kept handy.
In allergic or sensitive patients, it is better to inject the Anti-Snake Venom Serum under cover of anti-histamines and hydrocortisone (100 mg.) intramuscularly 15 to 30 minutes before the administration of Anti-Snake Venom Serum. The administration of adrenaline and hydrocortisone may be repeated if necessary.
When symptoms of snakebite are severe it may not be advisable to wait for 30 minutes to observe reactions to test-dose of serum. In such cases it may be better to inject 1 ml. of 1:1000 adrenaline intramuscularly at the same time as the serum in order to lessen the risk of anaphylaxis. Half the dose of adrenaline may be repeated 15 minutes later if necessary.
Dosing :
10 vials of polyvalent vials of ASV as the initial dose. For severe envenomation, can give almost upto 50 vials. Should be given IV over 1 hour.
Adverse Effect :
Before injection of Anti-Snake Venom Serum, history of prior injections of serum (e.g. anti-tetanus or anti-diphtheria serum), personal or familial history of allergy, i.e. asthma, eczema or drug allergy should be elucidated.
The sensitivity of the patient to Anti-Snake Venom Serum is tested by injecting subcutaneously 0.1 ml of this serum diluted 1:10. The patient should be observed for 30 minutes for local and general reactions. If the test dose shows either local reaction such as flare or general anaphylactic reaction such as pallor, sweating, nausea, vomiting, urticaria, and fall of blood pressure, these should be countered immediately by intramuscular injection of 1 ml of 1:1000. Adrenaline and with corticosteroids which should be always kept handy.
In allergic or sensitive patients, it is better to inject the Anti-Snake Venom Serum under cover of anti-histamines and hydrocortisone (100 mg.) intramuscularly 15 to 30 minutes before the administration of Anti-Snake Venom Serum. The administration of adrenaline and hydrocortisone may be repeated if necessary.
When symptoms of snakebite are severe it may not be advisable to wait for 30 minutes to observe reactions to test-dose of serum. In such cases it may be better to inject 1 ml. of 1:1000 adrenaline intramuscularly at the same time as the serum in order to lessen the risk of anaphylaxis. Half the dose of adrenaline may be repeated 15 minutes later if necessary.
Hypersensitivity reactions.
Hepatic Dose :
No dosage adjustments are recommended.