Pharmacokinetic evidence for the induction of lopinavir metabolism by efavirenz.
OBJECTIVE
The influence of efavirenz on lopinavir pharmacokinetics was investigated using a population approach.


METHODS
Forty-five HIV patients treated with lopinavir/ritonavir plus efavirenz (A) and 24 patients treated with lopinavir/ritonavir plus nucleoside/nucleotide reverse transcriptase inhibitors (B) were studied.


RESULTS
A relationship (P < 0.01) was established between the elimination rate constant of lopinavir (k(10)) and treatment with efavirenz. Mean k(10) was higher in group A than in group B (0.3838 vs 0.2810 h(-1)) (P < 0.001, 95% confidence interval for difference between means 0.1004, 0.1052).


CONCLUSIONS
These results suggest that lopinavir metabolism is induced by efavirenz.
Dailly
Eric
E
Clinical Pharmacology Department, Hôtel Dieu, Nantes, France. eric.dailly@chu-nantes.fr
Allavena
Clotilde
C
Raffi
François
F
Jolliet
Pascale
P
D000328:Adult; D000480:Alkynes; D019380:Anti-HIV Agents / Q000378:metabolism*; D048588:Benzoxazines; D003521:Cyclopropanes; D004338:Drug Combinations; D004347:Drug Interactions; D005260:Female; D017320:HIV Protease Inhibitors / Q000493:pharmacokinetics*; D006801:Humans; D061466:Lopinavir; D008297:Male; D010078:Oxazines / Q000494:pharmacology*; D011744:Pyrimidinones / Q000493:pharmacokinetics*; D019438:Ritonavir / Q000493:pharmacokinetics*
D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D004338:Drug Combinations; D017320:HIV Protease Inhibitors; D010078:Oxazines; D011744:Pyrimidinones; D061466:Lopinavir; C098320:efavirenz; D019438:Ritonavir