Objective: To establish whether an outpatient, 2-day oral desensitizat
ion protocol would be both sale and effective in HIV-infected patients
with previous trimethoprim-sulfamethoxazole (TMP-SMX) intolerance. De
sign: A single center trial of TMP-SMX desensitization in HIV-infected
patients with prior TMP-SMX hypersensitivity reactions. Methods: HIV-
infected patients with CD4 lymphocyte counts <250x10(6)/I cells or CD4
%<20% with previous non-life-threatening hypersensitivity reactions to
TMP-SMX were eligible. The desensitization protocol utilized 40 gradu
ated doses over 36 h; the first 28 doses (7.5 h) of the protocol were
given in an outpatient clinic with the remaining doses taken at home.
Results: Twenty-seven (60%) of the 45 subjects completed the protocol
and were subsequently maintained on daily TMP-SMX without adverse reac
tions (mean follow-up, 9 months; range, 4-16 months). Patients with CD
4 counts <100x10(6)/I cells were just as likely as patients with highe
r CD4 counts to tolerate the desensitization. No patient required hosp
italization for treatment of an adverse reaction. Conclusion: Oral des
ensitization to TMP-SMX in HIV-infected patients is a useful option in
the management of patients with advanced HIV disease and prior intole
rance to TMP-SMX.