Incidence and risk factors of rash associated with efavirenz in HIV-infected patients with preceding nevirapine-associated rash.

OBJECTIVE

To determine the incidence and risk factors of rash associated with efavirenz in HIV-infected patients with preceding nevirapine-associated rash.

METHODS

A retrospective cohort study was conducted in HIV-infected patients diagnosed with nevirapine-associated rash who subsequently received efavirenz between July 2003 and January 2005. Patients were followed up for 3 months after receiving efavirenz. Possible risk factors, including demographics, previous opportunistic infections, CD4 cell count, viral load, severity of nevirapine-associated rash and concurrent drugs, were studied and compared between those who had (group A) and did not have (group B) rash associated with efavirenz.

RESULTS

A total of 122 patients (52.5% male) were included in the study, with a mean age of 38.2 years. Median (and interquartile range) CD4 cell count and viral load were 55 (20-167) cells/microL and 86,150 (35,321-700,750) HIV-1 RNA copies/mL, respectively. Of the 122 patients, 10 (8.2%) developed rash associated with efavirenz and all required discontinuation of efavirenz. The baseline characteristics of group A (10 patients) and group B (112 patients) were similar. Median (and interquartile range) time from nevirapine discontinuation to efavirenz initiation was 12 (9-21) days in group A and 11 (7-21) days in group B (P=0.765). None of the risk factors investigated was associated with developing rash associated with efavirenz. The preceding development of severe nevirapine-associated rash had a trend towards a higher rate in group A than in group B (20.0% vs 10.7%; odds ratio=2.08; 95% confidence interval 0.39-10.97; P=0.322).

CONCLUSIONS

The majority (>90%) of HIV-infected patients with CD4 counts <200 cells/muL who had preceding nevirapine-associated rash could tolerate efavirenz well. Efavirenz may be an option for subsequent use in these patients, particularly in those who had preceding nevirapine-associated rash.