title: Efficacy and safety of rechallenge with low-dose trimethoprim-sulphamethoxazole in previously hypersensitive HIV-infected patients.
abstract: OBJECTIVE
  This study was undertaken to determine whether patients infected with HIV and with prior hypersensitivity to trimethoprim-sulphamethoxazole (TMP-SMX) can be rechallenged successfully with TMP-SMX, what factors predict successful rechallenge, and whether hypersensitivity is due to TMP or to SMX.
  
  
  METHODS
  A prospective, open study.
  
  
  METHODS
  A tertiary referral hospital.
  
  
  METHODS
  Thirty-one HIV-infected patients with a history of non-life-threatening hypersensitivity to TMP-SMX.
  
  
  METHODS
  Patients received TMP (300 mg twice a week) for 2 weeks and, where no major reaction occurred, subsequently with TMP-SMX (160 and 800 mg per tablet, one tablet two times a day, twice a week). Patients who developed significant and persistent hypersensitivity ceased SMX and were subsequently challenged with TMP-dapsone (300 and 100 mg, respectively, twice a week).
  
  
  METHODS
  That rechallenge is more likely to be successful in those with advanced HIV disease.
  
  
  RESULTS
  Five out of 31 (16%) patients developed hypersensitivity to TMP, and two ceased TMP as a result. Fifteen of the 26 (58%) patients who received subsequent TMP-SMX developed hypersensitivity, 12 of whom ceased TMP-SMX because of this reaction. Hypersensitivity to TMP-SMX was significantly less common in those with a CD4+ cell count < 20 x 10(6)/l than in those with a CD4+ cell count > 20 x 10(6)/l (31 versus 85%; P = 0.03). Hypersensitivity to TMP-dapsone occurred in two out of nine patients with hypersensitivity to TMP-SMX on rechallenge. One patient developed transient dyspnoea following a dose of SMX, but no other serious adverse drug reaction occurred.
  
  
  CONCLUSIONS
  Rechallenge with TMP-SMX appears safe in HIV-infected patients with a history of non-life-threatening hypersensitivity and is most likely to be successful in patients with a low CD4+ lymphocyte count. The data suggest a low rate cross-hypersensitivity between SMX and dapsone, at least at the doses used.
authors.affiliation: Centre for Immunology, St Vincent's Hospital, Sydney, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Carr
authors.forename: R
authors.initials: R
authors.lastname: Penny
authors.forename: D A
authors.initials: DA
authors.lastname: Cooper
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000517:prevention & control; D000328:Adult; D003429:Cross Reactions; D003875:Drug Eruptions / Q000150:complications / Q000209:etiology / Q000276:immunology; D004342:Drug Hypersensitivity / Q000150:complications / Q000209:etiology* / Q000276:immunology; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy*; D006801:Humans; D008297:Male; D016720:Pneumocystis Infections / Q000517:prevention & control; D012449:Safety; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology
chemical_list: D015662:Trimethoprim, Sulfamethoxazole Drug Combination