Efavirenz does not interact with the ABCB1 transporter at the blood-brain barrier

Pharm Res. 2006 Jul;23(7):1525-32. doi: 10.1007/s11095-006-0279-5. Epub 2006 Jun 21.


Purpose: This work characterizes the interactions between efavirenz (EFV) and P-glycoprotein (P-gp/ABCB1) at the blood-brain barrier (BBB) and predicts the possible consequences on the brain uptake of coadministered P-gp substrates.

Methods: The uptake of EFV was measured in whole brains of rat and mdr1a-/- and mdr1a+/+ mice, and in GPNT cells (rat brain endothelial cell line) with and without P-gp inhibitors (PSC833, S9788, Quinidine). The effect of a single dose or multiple doses of EFV on the P-gp functionality was evaluated in vivo and in vitro by measuring the brain and cell uptake of digoxin, completed by the analysis of the P-gp expression at the rat BBB after repeated administrations of EFV.

Results: Inhibition of P-gp did not alter the uptake of EFV in rat brain and GPNT cells. The EFV brain/plasma ratio in mdr1a-/- mice, lacking the expression of P-gp, was not different from that in mdr1a+/+ mice. Moreover, a single dose of EFV did not modify the uptake of digoxin in rat brain and GPNT cells. Finally, the 3-day exposure of GPNT cells to EFV did not have any effect on the uptake of digoxin. Similarly, the 7-day treatment with EFV did not change the uptake of digoxin in rat brain nor the expression of P-gp at the BBB.

Conclusion: EFV is strongly distributed in the brain, but is neither a substrate nor an inhibitor of the P-gp at the blood-brain barrier. On the other hand, EFV did not induce P-gp, allowing to sustain the brain accumulation of associated P-gp substrates such as protease inhibitors. These findings make EFV suitable for combinations circumventing the brain HIV-1 residency.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B
  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / antagonists & inhibitors
  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism*
  • ATP-Binding Cassette Transporters / antagonists & inhibitors
  • ATP-Binding Cassette Transporters / metabolism*
  • Alkynes
  • Animals
  • Benzoxazines
  • Blood-Brain Barrier / drug effects
  • Blood-Brain Barrier / metabolism
  • Brain / drug effects
  • Brain / metabolism*
  • Cell Line
  • Cyclopropanes
  • Cyclosporins / pharmacology
  • Digoxin / metabolism
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism
  • Male
  • Mice
  • Mice, Knockout
  • Oxazines / pharmacokinetics
  • Oxazines / pharmacology*
  • Piperidines / pharmacology
  • Quinidine / pharmacology
  • Rats
  • Rats, Wistar
  • Reverse Transcriptase Inhibitors / pharmacokinetics
  • Reverse Transcriptase Inhibitors / pharmacology*
  • Triazines / pharmacology


  • ATP Binding Cassette Transporter, Subfamily B
  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • ATP-Binding Cassette Transporters
  • Alkynes
  • Benzoxazines
  • Cyclopropanes
  • Cyclosporins
  • Oxazines
  • Piperidines
  • Reverse Transcriptase Inhibitors
  • Triazines
  • S 9788
  • Digoxin
  • Abcb1b protein, mouse
  • Quinidine
  • efavirenz
  • valspodar