Interindividual variability in efavirenz pharmacokinetics is not entirely explained by the well-recognized CYP2B6 516G-->T single nucleotide polymorphism. The aim of this study was to determine whether polymorphisms in the CYP2A6 gene can be used to enhance the predictability of efavirenz concentrations in human immunodeficiency virus (HIV)-infected native African patients.
Mid-dose efavirenz plasma concentrations were determined at 4 and 8 weeks following initiation of antiretroviral therapy in 65 HIV-infected Ghanaian patients. Selected CYP2B6 and CYP2A6 genotypes were determined by commercial 5'-nuclease assays. Relationships between averaged 4- and 8-week mid-dose efavirenz concentrations, demographic variables and genotypes were evaluated by univariate and multivariate statistical approaches including gene-gene interactions.
CYP2B6 c.516G-->T, CYP2B6 c.983T-->C, CYP2A6*9B and CYP2A6*17 allele frequencies were 45, 4, 5 and 12%, respectively. Rifampicin therapy, gender, age and body mass index had no significant influence on efavirenz mid-dose concentrations. Median efavirenz concentrations were more than five times higher (P < 0.001) in patients with CYP2B6 c.516TT genotype compared with GG and GT genotypes. Although none of the CYP2A6 genotypes was associated with altered efavirenz concentrations individually, CYP2A6*9B and/or CYP2A6*17 carriers showed a 1.8 times higher median efavirenz concentration (P= 0.017) compared with noncarriers. Multiple linear regression analysis indicated that the CYP2B6 c.516G-->T polymorphism and CYP2A6 slow-metabolizing variants accounted for as much as 36 and 12% of the total variance in efavirenz concentrations, respectively.
Our findings support previous work showing efavirenz oxidation by CYP2A6, and suggest that both CYP2A6 and CYP2B6 genotyping may be useful for predicting efavirenz plasma concentrations.
Pharmacology, Toxicology and Pharmaceutical Science
7
8%
Social Sciences
5
6%
Other
7
8%
Unknown
18
20%
Attention Score in Context
Attention Score in Context
This research output has an Altmetric Attention Score of 6. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 18 October 2016.
All research outputs
#7,432,872
of 34,054,827 outputs
Outputs from British Journal of Clinical Pharmacology
#2,020
of 6,916 outputs
Outputs of similar age
#43,149
of 248,893 outputs
Outputs of similar age from British Journal of Clinical Pharmacology
#10
of 35 outputs
Altmetric has tracked 34,054,827 research outputs across all sources so far. This one has received more attention than most of these and is in the 73rd percentile.
So far Altmetric has tracked 6,916 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 11.3. This one has gotten more attention than average, scoring higher than 64% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 248,893 tracked outputs that were published within six weeks on either side of this one in any source. This one has gotten more attention than average, scoring higher than 74% of its contemporaries.
We're also able to compare this research output to 35 others from the same source and published within six weeks on either side of this one. This one has gotten more attention than average, scoring higher than 62% of its contemporaries.
