Adverse Reactions to N-Acetylcysteine

Abstract

1 Clinical details of seven patients who suffered adverse reactions to N-acetylcysteine as Parvolex are documented. 2 Skin testing was carried out to diluted Parvolex, and its individual components N-acetylcysteine and ethylenediaminetetra-acetate, in five reacting patients and five patients who had received Parvolex with no ill-effects. 3 Weal responses to high concentrations (20 mg/ml) of acetylcysteine as Parvolex were significantly greater ( p < 0.02) in reactors. There were no other significant differences between the groups. 4 In two patients who reacted, the effects of intradermal Parvolex could be inhibited by prior therapy with the antihistamine terfenadine. 5 These results suggest a 'pseudo-allergic' rather than an immunological aetiology for adverse reactions to Parvolex.