Ethnic and gender differences in non-nucleoside reverse transcriptase inhibitor (NNRTI)-induced rash
     C Mazhude, S Jones, PJ Easterbrook, C Taylor The Caldecot Centre, Department of Genito-Urinary Medicine, Kings’ College Hospital, London, UK

Objective:
To determine the association of ethnic group and sex with the development of NNRTI-induced rash in a multiethnic cohort of HIV-infected patients.

Methods:
Retrospective record analysis of all patients starting nevirapine (NVP)/efavirenz (EFV) between Jan 1997 and Jan 2000. Sex, ethnic group and stage of disease were analysed as potential risk factors for the development of the rash.

Results:
A total of 337 records were analysed, including 285 patients on NVP and 52 on EFV. Of the 285 on NVP, 130 (46%) were white males, 93 (33%) black females, 48 (17%) black males and 9 (3%) white females. There was no significant difference in disease stage between the various ethnic groups (24% black females had prior AIDS-defining events vs. 19% of white males). Of the 285 on NVP, 21 (7%) developed a rash, and two-thirds of these discontinued as a result. Of those that developed a rash, 13 (62%) were black females, two (10%) white females, five (24%) white males and one (5%) black male. Female sex was associated with the highest incident risk of 15% (black women 14%, white women 22%) vs. 2–4% for males. Only two patients with a rash had prior AIDS-defining events. Two-thirds were on 400 mg NVP when the rash occurred. The median time to rash was 15 days (range 2–39). Three patients developed a Steven–Johnson type syndrome (two black females, one white male). Of nine developing a rash on NVP and switching to EFV, none had a recurrence. Of the 52 started on EFV, only one white male developed a rash and the drug was stopped.

Conclusions:
The 7% incidence of rash in those starting NVP falls within ranges described previously. Female sex is strongly associated with a higher risk of NVP-induced rash. These data do not suggest a difference in the risk of NVP rash on the basis of black/white ethnicity. (Commentary from Jules Levin: recent data reported at the Pharmacology Workshop in the Netherlands suggests that body weight may be crucial factor and possibly not gender. However, gender differences in pharmacokinetics or other gender differences may also play a role. Interstingly, although authors conclude there was no ethnic difference white women had less rash than black women 62% vs 10%).