New scheme of oral rapid desensitization to TMP-SMX in HIV-infected patients. Efficacy and safety

Abstract

Rationale Trimethoprim Sulfamethoxazole (TMP-SMX) represents the first-line treatment to HIV-seropositive patients for prophylaxis or treatment of pneumonia for Pneumocistis Carini, but is commonly discontinued because of hypersensitivity reactions. Different studies have tried long and short desensitization schemes, with a efficacy from 30 to 100%. In our country TMP-SMX represents the more accessible therapy for the HIV infected patient. The objective of our study was to evaluate safety and efficiency of a protocol of rapid oral desensitization to TMP-SMX (5 hours) in previously hypersensitive patients. Methods The design of the study was prospective, open and with a 6 months length. Informed Consent was signed by all the patients. Sixteen patients were desensitized increasing concentrations every 15 minutes until 320 mgs of TMP, with a challenge 48 later with the same dosage. Results Eighty one per cent of the patients were AIDS cases according CDC (Center for Disease Control) classification system from 1993. None of the patients had alterations on hepatic enzymes, hematologic parameters, urea and creatinine. Seventy per cent did not present reaction of hypersensitivity even after the challenge, and after taking TMP on next times and 5% diminished the severity of symptoms, being statistically significant with p<0,05 (0,0067 and 0,0030 according to Test Wilcoxon and Mann-Whitney respectively). Desensitization failed in 25%. No life-threatening reactions occurred nor statistically significant alterations on the laboratory parameters after the desensitization. Conclusions The protocol of desensitization rapid is a simple, safe and effective method since it allows the administration of TMP-SMX in 75% of desensitized patients.