ANAPHYLACTOID SKIN REACTIONS AFTER INTRAVENOUS REGIONAL ANESTHESIA USING 0.5-PERCENT PRILOCAINE WITH OR WITHOUT PRESERVATIVE A DOUBLE-BLIND-STUDY

Methylparaben, the preservative of various local anaesthetic solutions , is a potential allergen. In a double-blind study, 0.5% prilocaine wi th (Citanest(R), n=100) or without (n=100) methylparaben were compared for the occurrence of skin reactions after intravenous regional anaes thesia of the arm in surgical patients. Skin reactions were registered after the deflation of the tourniquet, cuff and intradermal tests wer e performed with 0.5% prilocaine, 0.1% methylparaben and saline in all patients. Seventeen patients in the Citanest(R) group and Four patien ts in the methylparaben-free prilocaine group developed erythematous s kin reactions in the exposed arm after deflation of the tourniquet cuf f (P<0.05, between the groups). The skin symptoms disappeared within a n hour and were always restricted to the region which had been anaesth etised. None of the affected patients had positive intradermal tests. The observed skin reactions are probably non-IgE-mediated anaphylactoi d reactions in which the presence of methylparaben in the local anaest hetic solution plays a major role.