Original Research

Correlation of hair and plasma efavirenz concentrations in HIV-positive South Africans

Jenna Johnston, Lubbe Wiesner, Peter Smith, Gary Maartens, Catherine Orrell
Southern African Journal of HIV Medicine | Vol 20, No 1 | a881 | DOI: https://doi.org/10.4102/sajhivmed.v20i1.881 | © 2019 Jenna Johnston, Lubbe Wiesner, Peter Smith, Gary Maartens, Catherine Orrell | This work is licensed under CC Attribution 4.0
Submitted: 04 July 2018 | Published: 29 April 2019

About the author(s)

Jenna Johnston, Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
Lubbe Wiesner, Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
Peter Smith, Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
Gary Maartens, Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
Catherine Orrell, Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine, Cape Town, South Africa; and, Department of Medicine, University of Cape Town, Cape Town, South Africa, South Africa


Share this article

Bookmark and Share

Abstract

Background: Antiretroviral concentrations in hair provide a longer window of drug detection and are useful for measuring longer-term drug exposure. Efavirenz is an important component of first-line treatment in resource-limited settings, but its concentrations in hair have not been well studied.

Methods: This study is a supplementary to a randomised controlled trial of an adherence intervention using an electronic adherence measuring device. Hair and plasma samples were collected from human immunodeficiency virus-positive patients in Cape Town, South Africa. Previously validated liquid chromatography tandem mass spectrometry methods were used to measure efavirenz concentrations in the collected hair and plasma samples. CYP2B6 genotyping of participants was also performed. Data analysis was performed using descriptive and comparative statistics as well as regression modelling.

Results: Hair samples were collected from 59% of patients enrolled in the parent study. Results indicated that hair efavirenz concentrations were significantly influenced by participants’ CYP2B6metaboliser status. Median efavirenz concentrations for extensive, intermediate and slow metaboliser genotypes were 3.54 ng/mg, 5.11 ng/mg and 10.66 ng/mg, respectively. A strong correlation was observed between the efavirenz concentrations measured in hair and plasma samples (Spearman’s correlation coefficients, 0.672–0.741, p < 0.0001). No relationship between hair efavirenz concentrations and virological failure or adherence measured using an electronic adherence was shown.

Conclusion: The results from this study provide further insight into the potential of using hair as a matrix for measuring antiretroviral concentrations. However, challenges experienced in collecting hair samples suggest that this adherence measure may have limited utility in an African population.


Keywords

Adherence; Antiretroviral therapy; Hair; Plasma; Drug concentrations

Metrics

Total abstract views: 491
Total article views: 235


Crossref Citations

No related citations found.