DRUG-ATTRIBUTED ANAPHYLAXIS

Allergic type I reactions to medicines range in their clinical present ation from rhinitis and urticaria to severe bronchoconstriction and an aphylactic shock. We examined all cases of suspected drug induced reac tions classified as anaphylactic reactions or shock reported in Sweden between 1972 and 1995 with regard to patient characteristics and drug (s) suspected. Some comparisons with drug sales and prescription data were also made. During the study period of a total of 1338 reports con cerned anaphylactic/oid shock or reactions with at least a possible ca usal relation to medicine giving an overall reporting rate of seven ca ses per million inhabitants per year of drug-induced anaphylaxis. Of t hese 1338 patients 51 (3.8%) died from their reactions. Among the non- fatal cases, 460 (34.4%) were diagnosed as shock and 827 (61.8%) as an aphylactic reactions. In total 46.3% of all reports concerned men but men were overrepresented among the older patients and among the fatal cases (65%). There were 201 different drugs reported as 'suspected' th em most common of which were dextrans (418 reports), X-ray contrast me dia (161 reports) and antibiotics (153 reports). For dextrans the rate of anaphylactic reactions, shock and fatal cases reported were 128,10 1 and 21 per million bottles respectively. This decreased to 10.3, 9.8 , and 0.4 per million bottles after the introduction of preventive tre atment with dextran 1 in 1983. The reporting rate for ionic contrast m edia were 0.14, 0.13 and 0.02 per 1000 l for reactions, shock and fata l cases respectively whilst for non-ionic contrast media they were 0.7 /1000 l for reactions, 0.02/ 1000 1 for shock, but there was no report of a fatal case. For phenoxymethylpenicillin the reported rate of ana phylaxis was 0.14 cases per million defined daily doses and for benzyl penicillin it was 3.7 cases per million defined daily doses. During th e study period several drugs have been identified as important causes of anaphylaxis and measures have been taken to decrease the risk of an aphylaxis e.g. the introduction of preventive treatment with dextran 1 , the shift from ionic to non-ionic contrast media and the abolition o f polyethoxylated castor oil as a solvent. Spontaneous reporting of dr ug-induced anaphylaxis remains an important surveillance model but nee ds to be complemented by better quantitative methods. (C) 1998 John Wi ley gr Sons, Ltd.