Efficacy and safety of desensitization with sulfamethoxazole and trimethoprim in 48 previously hypersensitive patients infected with human immunodeficiency virus

Objective: To study the safety and efficacy of desensitization with the use of a combination product of sulfamethoxazole and trimethoprim in previously hypersensitive patients infected with the human immunodeficiency virus. Design: Prospective survey, with a median follow-up of 16 months (range, 5-24 months). Setting: Day-care hospital in a referral center. Patients: All human immunodeficiency virus-infected patients who had a history of allergic reactions leg, rash) to sulfamethoxazole-trimethoprim and who required sulfamethoxazole-trimethoprim prophylaxis. Intervention: The desensitization procedure took 2 days. The full dose (sulfamethoxazole-trimethoprim, 400-80 mg) was reached on the third day according to the following schedule: day 1-4-0.8 mg at 9 AM, 8-1.6 mg at 11 AM, 20-4 mg at 1 PM, and 40-8 mg at 5 PM; day 2-80-16 mg at 9 AM, 160-32 mg at 3 PM, and 200-40 mg at 9 PM; and day 3-400-80 mg at 9 AM. Main Outcome Measurer The onset of cutaneous adverse effects attributable to sulfamethoxazole-trimethoprim therapy within 3 months after desensitization. Results: Of the 48 evaluable patients, 37 (77%) tolerated sulfamethoxazole-trimethoprim desensitization without toxic effects and continued to take sulfamethoxazole-trimethoprim daily. Desensitization failed in 11 cases (5 on day 1, 3 on day 2, and 1 each on days 9, 11, and 90). Acute hypotension and a nonfatal myocardial infarction developed in 1 of these patients. The factors that were predictive of failure were a relatively high CD4(+) cell percentage (11% vs 8%; P=.008) and a relatively high CD4(+)/CD8(+) ratio (0.27 vs 0.12; P=.02). Conclusions: The efficacy of desensitization with sulfamethoxazole-trimethoprim was confirmed; this desensitization procedure was more often Successful in patients with lower CD4(+) cell percentages and CD4(+)/CD8(+) ratios. However, sulfamethoxazole-trimethoprim therapy should be reintroduced carefully.