Multiple-dose pharmacokinetics of efavirenz with and without the use of rifampicin in HIV-positive patients.

Rifampicin (RIF) decreases serum concentrations of several antiretroviral drugs. We carried out a prospective, comparative study to define efavirenz (EFV) pharmacokinetics in 16 cases and 13 controls. Cases were HIV and tuberculosis (TB) co-infected adults assuming RIF 600 mg once daily and EFV 800 mg once daily. Patients on EFV at standard 600 mg dose without RIF were taken as controls. EFV levels in plasma were assayed by high-performance liquid chromatography (HLPC) predose (C(trough)) and at 1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 13, 14, 16, 18, 22 and 24 hours post-dose, and pharmacokinetic parameters were determined by non-compartmental methods. Among cases, 81% were males, mean age was 37 years, 50% were Caucasians, mean weight was 64 kg, mean CD4 cell counts and log HIV RNA copies were 160/microl and 5.2 /microl, respectively. Cases had a significantly higher Cl/F/kg if compared with controls (0.269 +/- 0.12 versus 0.167 + 0.05 L/h/kg, p<0.01). Otherwise, dose-dependent pharmacokinetic parameters of EFV were similar between cases and controls. Interindividual variability was consistently higher among TB cases compared to controls for all considered parameters. All cases completed combined treatment and no increased EFV toxicity was observed. These results suggest that a dose of 800 mg of EFV in association with rifampicin may be appropriate for patients of weight > 60 kg in Europe. Therapeutic drug monitoring may be beneficial for patients on combination therapy with RIF.

Vaginal colonization with Candida spp. in human immunodeficiency virus-infected women: a cohort study.

We have conducted a longitudinal study on factors associated with candidal vaginal colonization, a precursor of vaginitis, in a cohort of HIV-infected women in Italy. All consecutive women attending a single, tertiary care clinical site were offered free screening for sexually transmitted infections and genital disorders every 6-12 months. Candidal vaginal colonization was defined as a positive culture for Candida spp. in an asymptomatic woman. From January 1998 to July 2002 we analysed 214 women. The baseline prevalence of candidal vaginal colonization was 16.8%. In the logistic regression analysis, the time since HIV infection > or =36 months (odds ratio [OR] = 0.18, 95% confidence interval [CI] 0.016-0.53, P = 0.002) and a plasma viral load > or =10,000 copies/mL (OR = 3.9, 95% CI 1.03-14.9, P = 0.045) were independently associated with candidal colonization. Among 130 women who were followed for a mean period of 24 months, the incidence of vaginal colonization was 10.7/100 women-years. In the Cox regression analysis, a CD4(+) T-lymphocytes count <100 cells/microL during the follow-up was associated with an increased risk of candidal vaginal colonization (OR = 4.45, C.I. = 1.20-16.81, P = 0.03). Risk of candidal vaginal colonization episodes in HIV-infected women significantly increase when CD4(+) T-lymphocytes are less than 100.