Does tenofovir influence efavirenz pharmacokinetics?

Rotger, Margalida; Colombo, Sara; Furrer, Hansjakob; Décosterd, Laurent; Buclin, Thierry; Telenti, Amalio (2007). Does tenofovir influence efavirenz pharmacokinetics? Antiviral therapy, 12(1), pp. 115-8. London: International Medical Press

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INTRODUCTION: A recent report described a possible interaction between tenofovir (TFV) and efavirenz (EFV). Patients developed neuropsychiatric manifestations upon introduction of TFV on a stable EFV-containing regimen. We evaluated the possibility of a pharmacokinetic interaction between TFV and EFV by assessing cross-sectional and longitudinal data in 169 individuals receiving EFV. RESULTS: EFV plasma area-under-the-curve (AUC) levels were comparable among individuals receiving (n=18) or not receiving TFV (n=151); 57,962 versus 52,293 ng*h/ml. However, under conditions of limited EFV metabolism, that is, the group of 23 individuals carrying two copies of CYP2B6 loss/diminished-function alleles, plasma AUC values were highest among individuals receiving TFV (n=5, 353,031 ng*h/ml), compared with those not receiving TFV (n=18, 180,689 ng*h/ml). Statistical analysis identified both a global, sixfold effect of CYP2B6 loss/diminished function (P < 0.0001) and a significant interaction between the number of loss/diminished-function alleles and the co-medication with TFV (P = 0.009). CONCLUSION: Although there is no clear evidence for a pharmacokinetic interaction between TFV and EFV, we cannot rule out an interaction between these drugs restricted to individuals who are slow EFV metabolizers.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Infectiology

UniBE Contributor:

Furrer, Hansjakob






International Medical Press




Factscience Import

Date Deposited:

04 Oct 2013 14:59

Last Modified:

05 Dec 2022 14:18

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Web of Science ID:


URI: (FactScience: 60458)

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