P-glycoprotein-mediated efflux of antiepileptic drugs: preliminary studies in mdr1a knockout mice.

Abstract

Evidence suggests that the efflux transporter P-glycoprotein (P-gp) may play a facilitatory role in refractory epilepsy by limiting the brain access of antiepileptic drugs (AEDs). We have conducted a preliminary pharmacokinetic study of seven commonly used AEDs in mdr1a knockout mice, devoid of P-gp at the blood-brain barrier. A parallel group of matched wild-type mice served as controls. AEDs were administered by subcutaneous injection and serum and brain drug concentrations determined at 30, 60, and 240min post-dosing. The brain-serum concentration ratio for topiramate was higher in mdr1a(-/-) mice than in wild-type controls at all time points investigated. No consistent effects were observed with any other AED investigated. These findings suggest that topiramate may be a substrate for P-gp-mediated transport. Further studies employing a range of model systems are required to substantiate this observation and to address the potential role of drug transporters in refractory epilepsy.

• Authors: Graeme J. Sills, Patrick Kwan, Elaine Butler, Elizabeth C.M. de Lange, Dirk Jan van den Berg, Martin J. Brodie
• Journal: Epilepsy & behavior : E&B (Epilepsy Behav) Vol. 3 Issue 5 Pg. 427-432 (Oct 2002) ISSN: 1525-5069 [Electronic] United States
• PMID: 12609264 (Publication Type: Journal Article)