Center for Human Genetics and Laboratory Diagnostics, Dr. Klein, Dr. Rost and Colleagues

You are here: Pharmacogenetics » HIV Treatment (Overview) » HIV Treatment - Efavirenz

HIV Treatment - Efavirenz [T88.7]

OMIM number: 123930 (CYP2B6)

Dipl.-Biol. Birgit Busse

Scientific Background

Genetic disposition of a patient is one factor determining the compatibility of HIV treatment with efavirenz. The enzyme CYP2B6 is involved in the metabolism of various NNRTIs (non-nucleoside reverse transcriptase inhibitors), such as efavirenz.

The CYP2B6*6 allele (c.516G>T) is associated with a reduced enzyme activity. Several studies showed an elevated plasma level of the active agent in homozygous carriers of the CYP2B6*6 allele (T/T genotype). In these patients, side-effects caused by efavirenz arise with higher frequency (prescribing information Sustiva®). Among all Caucasians, the frequency for the homozygous T/T genotype is approximately 5%.