Antivenom treatment

Antivenom treatment can be complicated by early reactions (anaphylaxis), pyrogenic reactions, or late reactions (serum sickness-type). The incidence and severity of early reactions is proportional to the dose of antivenom and the speed with which it enters the blood stream (1,2). These reactions usually develop within 10-180 minutes of starting antivenom therapy. The reported incidence of early reactions after intravenous antivenom in snakebite patients, which ranges from 43% (3) to 81% (4), appears to increase with the dose and decrease when refined antivenom is used and administration is by intramuscular rather than intravenous injection. Unless patients are watched carefully for 3 hours after treatment, mild reactions can be missed and deaths misattributed to the envenoming itself. In most cases symptoms are mild urticaria, nausea, vomiting, diarrhea, headache, and fever however, in up to 40% of cases severe systemic anaphylaxis develops, with bronchospasm, hypotension, or angioedema. However, deaths are rare (5). 

McKenna, W.R., 1992, Africanized honeybees Proposed antivenom treatment and first case of massive sting in the U.S. J. Allergy Clin. Immunol. 89 294. (abstract)... 

The phenomenon of plasma sequestration and redistribution has been observed for digitalis, colchicine and phencyclidine after Fab infusion (Smith et al, 1976 Sabouraud et al, 1992 Valentine et al, 1994). Such experiments could also be used to determine the optimal route for serum administration, to test the efficiency of a precocious or a delayed serotherapy, to define the dose of antivenom for optimal efficacy and to compare the relative effectiveness of different preparations of antivenoms. Studies similar to those carried out in the case of viper envenomations could be performed in the case of envenomations by other snakes or by scorpion stings and would help to rationalize antivenom treatment. 

The Indian folk medicine, called Ayurvedic medicine, can be traced back 3000-5000 years and was practiced by the Brahmin sages of ancient times. The treatments were set out in sacred writings called Vedas. The material medica are extensive and most are based on herbal formulations. Some of the herbs have appeared in Western medicines, such as cardamom and cinnamon. Susruta, a physician in the fourth century ad, described the use of henbane as antivenom for snakebites. 

Patients with systemic symptoms should be considered for treatment with antivenoms. Clinicians are not in agreement as to the exact criteria, and few randomized controlled trials have been conducted. 

Where the snake has been identified and specific antivenom is available, then this should be used. However, since treatment is urgent, and identification of snakes is difficult, in many Asian countries polyvalent antivenom is used. The Indian anti-snake venom (ASV), manufactured by Serum Institute India, Pune, and Haffkine Bio Pharmaceutical Corporation, Mumbai, consists of hyperimmune horse serum against four common snakes - cobra, common krait, Russell s viper and saw-scale viper. 

Offerman SR, Bush SP, Moynihan JA, Clark RF. Cro-taline Fab antivenom for the treatment of children with rattlesnake envenomation. Pediatrics 2002 110(5) 968-71. 

Although treatment is possible using antivenins (antivenom), the combinations of toxins in a particular snake venom can vary, which means that they need to be as specific as possible. Antidotes to the effects can sometimes also be used, for example anticholinesterase substances which are used in treatment of the death adder bite. The antidote stops the... 

Pyrogenic reactions result from contamination of antivenom by endotoxin-like compounds. High fever develops 1-2 hours after treatment and is associated with rigors, followed by vasodilatation and a fall in blood pressure. Febrile convulsions can occur in children. Patients should be cooled and given antipyretic drugs by mouth, powdered and washed down a nasogastric tube, or by suppository. 

Clark RF, Williams SR, and Nordt SP (1997) Successful treatment of crotalid-induced neurotoxicity with a new polyspecific crotalid Fab antivenom. Annals of Emergency Medicine 310 54-57. 

Venomous snakes and venom have always been of interest to biologists. Historically, snake venoms were viewed as a valuable aid and were frequently used in early medical therapies. Ancient Egyptian and Chinese physicians utilized snake venoms as treatment for a variety of ailments and diseases. For over a century, snake venom has been used to develop antivenoms to treat snakebite envenomation. Currently, there are over 30 facilities worldwide that produce 120 different commercially available antivenoms. These antivenoms include both monovalent forms (effective for a specific species) and polyvalent forms (generally effective for several species that occur... 

Dart RC, Seifert SA, Boyer LV, et al. A randomized multicenter trial of Crotalidae polyvalent immune Fab (ovine) antivenom for the treatment for crotaline snakebite in the United States. Arch Intern Med 2001 161 2030-2036. 

A. kaempferi Yellowmouth, Dutchman s pipe whole plant treatment of asthma, cough and piles as antivenomous, antibacterial, antipruritic, hypotensive, expectorant, and emetic 60... 

II. Indications. Antivenom is used for treatment of significant envenomation by Crotalinae species (see Section II, p 343). 

A. Adjunctive with H., blockers such as diphenhydramine (see p 436) in the management and prophylactic treatment of anaphylactic and anaphylactoid reactions (see Antivenoms, pp 407-410). 

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