Antivenom use in Australia. Premedication, adverse reactions and the use of venom detection kits.

OBJECTIVES: To analyse reports of antivenom use and sequelae in Australia from July 1 1989 to June 30 1990. The value of snake venom detection kits (VDKs) was also analysed.

METHODS: Information was obtained from antivenom usage reports returned to the Commonwealth Serum Laboratories and from personal letters sent to those reporting doctors. Information on VDKs was obtained from antivenom usage reports or from questionnaires packaged with VDKs.

RESULTS: Reported antivenoms used were: red-back spider, 258 cases; funnel-web spider, 3 cases; stonefish, 26 cases; box jellyfish, 6 cases; snake, 91 cases. Immediate reactions followed administration of red-back spider antivenom in only two patients and snake antivenoms in four patients. Delayed reactions (serum sickness) followed use of red-back spider antivenom in three patients, stonefish antivenom in two, and snake antivenoms in three. No reaction was life-threatening. Premedication was used in the majority of red-back spider bites and in 66 of 86 snake bites. Oral corticosteroids were given prophylactically after some uses of snake antivenom to prevent serum sickness. VDKs were used in 181 cases of snake bite and were reported as being useful in selecting appropriate snake antivenom in 31% of cases of antivenom use. (Only 10 of these 181 were also reported on the antivenom usage report.) Appropriate first aid was given in 61% of cases. There were 50% fewer snake bites reported than 10 years ago.

CONCLUSIONS: Antivenoms in Australia are well tolerated with few immediate or delayed reactions. The use of premedication and prophylactic oral corticosteroids for four to five days after antivenom administration may be responsible for this low reaction rate. VDK results help select the appropriate antivenom; however, in some cases positive results were obtained from urine samples from patients with no symptoms of envenomation.