Abstract
Background
The use of rifamycin antibiotics for TB prevention carries a risk of detrimental drug–drug interactions with concomitantly used ART.
Objectives
To evaluate the interaction of the antiretroviral drug nevirapine in combination with 4 weeks of daily rifapentine and isoniazid for TB prevention in people living with HIV.
Methods
Participants were individuals enrolled in the BRIEF-TB study receiving nevirapine and randomized to the rifapentine/isoniazid arm of the study. Participants provided sparse pharmacokinetic (PK) sampling at baseline and weeks 2 and 4 for trough nevirapine determination. Nevirapine apparent oral clearance (CL/F) was estimated and the geometric mean ratio (GMR) of CL/F prior to and during rifapentine/isoniazid was calculated.
Results
Seventy-eight participants had evaluable PK data: 61 (78%) female, 51 (65%) black non-Hispanic and median (range) age of 40 (13–66) years. Median (IQR) nevirapine trough concentrations were: week 0, 7322 (5266–9302) ng/mL; week 2, 5537 (3552–8462) ng/mL; and week 4, 5388 (3516–8243) ng/mL. Sixty out of 78 participants (77%) had nevirapine concentrations ≥3000 ng/mL at both week 2 and 4. Median (IQR) nevirapine CL/F values were: week 0 pre-rifapentine/isoniazid, 2.03 (1.58–2.58) L/h; and during rifapentine/isoniazid, 2.62 (1.81–3.42) L/h. The GMR (90% CI) for nevirapine CL/F was 1.30 (1.26–1.33).
Conclusions
The CL/F of nevirapine significantly increased with concomitant rifapentine/isoniazid. The decrease in nevirapine trough concentrations during rifapentine/isoniazid therapy suggests induction of nevirapine metabolism, consistent with known rifapentine effects. The magnitude of this drug–drug interaction suggests daily rifapentine/isoniazid for TB prevention should not be co-administered with nevirapine-containing ART.
Antiretroviral drug interactions: often unrecognized, frequently unavoidable, sometimes unmanageable
