MANAGEMENT OF ADVERSE REACTIONS TO PROPHYLACTIC TRIMETHOPRIM-SULFAMETHOXAZOLE IN PATIENTS WITH HUMAN-IMMUNODEFICIENCY-VIRUS INFECTION

Background: In hospitals attended by patients with human immunodeficie ncy virus infection, adverse reactions are often observed to trimethop rim-sulfamethoxazole, particularly cutaneous reactions. Given the impo rtance of this drug for prophylaxis we have attempted to establish a d esensitization or tolerance protocol so that patients can continue the drug without repeated adverse reactions. Methods: We studied 34 HIV p atients with adverse cutaneous reactions to trimethoprim-sulfamethoxaz ole, slight to moderate in nature but not life-threatening. Skin tests (prick and intradermal) were done in an attempt to rule out a mechani sm of hypersensitivity. Subsequently, trimethoprim-sulfamethoxazole wa s administered orally in increasing doses beginning with trimethoprim, 0.2 mg, and sulfamethoxazole, 1 mg. The same dose was repeated after 12 hours and then doubled every 24 hours until the therapeutic dose wa s achieved. If adverse reactions appeared we maintained the last dose administered and administered antihistamines until the reactions clear ed or improved. Results: None of the patients had positive skin tests (immediate or delayed). Twenty-seven patients were satisfactorily dese nsitized. After a follow-up of 3 months, 25 patients were still incide nt-free on trimethoprim-sulfamethoxazole prophylaxis, and 19 returning for check-ups at 6 months could still tolerate the drug well. Conclus ions: Our data indicate that patients with adverse reactions to trimet hoprim-sulfamethoxazole can continue prophylactic treatment after oral desensitization.