Decreased incidence and mortality of anaphylaxis to chymopapain

A recognized side effect of chemonucleolysis is life-threatening anaphylaxis to chymopapain. In the clinical trials of chymopapain, 13 cases of anaphylaxis were reported in 1585 administrations (0.82%). Two patients died. Data from a postmarketing survey (48,239 questionnaires) were reviewed to identify factors influencing the incidence and severity of anaphylaxis. The results indicate the incidence of anaphylaxis decreased to 0.44% in the 1983-1984 period (126/23,736), a level significantly (P less than or equal to 0.001) below the incidence of 0.82% observed in initial clinical trials. Only three deaths from complications related to anaphylaxis occurred in approximately 75,000 administrations (producing 252 anaphylactic episodes) reported since December 1982. The prophylactic use of antihistamines and pretreatment with intravenous fluids coincide with the dramatic reduction in mortality due to anaphylaxis. However, overdiagnosis of anaphylaxis in the clinical trials and avoidance of chemonucleolysis in patients with IgE antibodies to chymopapain may account, in part, for the reduction in incidence.