Increasing nevirapine dose can overcome reduced bioavailability due to rifampicin coadministration.
We studied the effect of rifampicin on steady-state pharmacokinetics of nevirapine and the impact of increasing the dose of nevirapine on its peak (Cmax) and trough (Cmin) levels in 13 HIV-infected patients on regular antiretroviral treatment with nevirapine-containing regimens (200 mg twice daily). A baseline pharmacokinetic study was conducted and repeated after 1 week of daily rifampicin (450/600 mg). The study was repeated in 7 of 8 patients who had subtherapeutic Cmin nevirapine levels after increasing nevirapine dose to 300 mg twice daily. Liver function was monitored. Rifampicin caused significant reductions in Cmax (42%), Cmin (53%), and exposure (46%) of nevirapine (P <.01). The Cmin of nevirapine fell below the therapeutic range of 3 microg/ml in 8 of 13 patients. An increase of nevirapine to 300 mg twice daily raised Cmin to therapeutic range in all 7 patients without exceeding the toxic level of 12 microg/mL. There were no clinical or laboratory adverse events. Our findings suggest that decreased bioavailability of nevirapine because of rifampicin coadministration could be overcome by increasing the dose of nevirapine from 200 to 300 mg twice daily without short-term adverse events. Further studies to evaluate the long-term safety of higher dose of nevirapine are required.
Ramachandran
Geetha
G
HIV/AIDS Division, Tuberculosis Research Centre (Indian Council of Medical Research), Chennai, India.
Hemanthkumar
Agibothu K
AK
Rajasekaran
Sigamani
S
Padmapriyadarsini
Chandrasekaran
C
Narendran
Gopalan
G
Sukumar
Baluswamy
B
Sathishnarayan
Srinivasan
S
Raja
Krishnaraj
K
Kumaraswami
Vasanthapuram
V
Swaminathan
Soumya
S
D000284:Administration, Oral; D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D000904:Antibiotics, Antitubercular / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics; D004334:Drug Administration Schedule; D004347:Drug Interactions; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism*; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D019829:Nevirapine / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism*; D012293:Rifampin / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics; D014376:Tuberculosis / Q000150:complications / Q000188:drug therapy*
D019380:Anti-HIV Agents; D000904:Antibiotics, Antitubercular; D018894:Reverse Transcriptase Inhibitors; D019829:Nevirapine; D012293:Rifampin