Some individuals have higher efavirenz plasma concentrations during rifampin-containing tuberculosis (TB) therapy, contrary to the expected induction effect of rifampin. Among HIV-infected patients without (n = 38) and with TB on rifampin-containing therapy (n = 18), we tested the hypothesis that drug–gene interaction may explain the highly variable drug interactions. Two-way analysis of variance revealed a significant interaction between CYP2B6 516G→T polymorphism and rifampin-containing therapy, suggesting that efavirenz dose adjustment may need to be individualized on the basis of the patient's genotype.
aThe Miriam Hospital
bWarren Alpert Medical School of Brown University, Providence, Rhode Island
cUniversity of Ghana Medical School, Accra, Ghana
dDepartment of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, Massachusetts, USA.
Received 30 September, 2010
Accepted 8 November, 2010
Correspondence to Awewura Kwara, MD, The Miriam Hospital, 164 Summit Avenue, Providence, RI 02906, USA. Tel: +1 401 793 2463; fax: +1 401 793 4704; e-mail: email@example.com