BHIVA treatment guidelines for tuberculosis (TB)/HIV infection 2005

Pozniak, Anton; Miller, R F; Lipman, Marc; Freedman, Andrew; Ormerod, L.P.; Johnson, Margaret; Collins, Sean E; Lucas, SB

doi:10.1111/j.1468-1293.2005.00293.x

Cited by 62 publications

(63 citation statements)

References 112 publications

(113 reference statements)

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“…Efavirenz-containing highly active antiretroviral therapy (HAART) is also preferred in patients with tuberculosis co-infection requiring rifampicincontaining therapy [1]. Although its safety profile is considered satisfactory, central nervous system (CNS) side effects are commonly reported.The CNS side effects range from headaches and dizziness to insomnia, hallucinations, acute mania and psychosis [2].…”

Section: Introductionmentioning

confidence: 99%

Pharmacogenetic markers of CYP2B6 associated with efavirenz plasma concentrations in HIV‐1 infected Thai adults

Sukasem

Cressey

Prapaithong

et al. 2012

Brit J Clinical Pharma

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WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• Interindividual variability in efavirenz plasma concentrations is associated with CYP2B6 genetic polymorphisms.• Twenty‐nine different alleles of the CYP2B6 gene are listed. CYP2B6*6, *9, *16, *26, *27 and *28 carriers are reported to be associated with slower efavirenz oral clearance.• The allelic variant 516G>T is associated with diminished activity of CYP2B6 and high efavirenz plasma concentrations are associated with an increase risk of neuropsychological toxicity.WHAT THIS STUDY ADDS• This study identified three SNPs in the CYP2B6 gene which could potentially act as additional independent predictors of efavirenz plasma concentrations beyond that provided by the CYP2B6 c.516G>T polymorphism.• The GAC‐CYP2B6 haplotype (G516T/A785G/C21563T) is associated with higher plasma efavirenz concentrations in HIV‐infected Thai adults.• The CYP2B6 g.18492 T>C polymorphism was significantly associated with lower efavirenz concentrations than those with the homozygous wild‐type.AimsTo investigate the frequency of CYP2B6 polymorphisms and the influence of haplotype structure on plasma efavirenz concentrations in Thai adults with HIV‐1 infection.MethodsGenotyping of nine single nucleotide polymorphisms (SNPs, c.64C>T, c.499C>G, c.516G>T, c.785A>G, c.1375A>G, c.1459C>T, g.3003T>C, g.18492C>T and g.21563C>T) of CYP2B6 were performed using real‐time PCR‐based allelic discrimination on blood samples from 52 HIV‐infected adults who had received an efavirenz‐based regimen. Plasma efavirenz concentrations were measured by high performance liquid chromatography.ResultsThe minor allele frequencies for c.64C>T, c.516G>T, c.785A>G, g.3003C>T, g.18492T>C and g.21563C>T were 0.087, 0.365, 0.413, 0.308 and 0.356, respectively. However, no variant alleles were identified for three SNPs (c.499 C>G, c.1375 A>G and c.1459 C>T). Efavirenz plasma concentrations were significantly associated with c.516G>T (P= 0.0095), c.785A>G (P= 0.0017), g.21563C>T (P= 0.0036) and g.18492C>T (P= 0.0011). The composite CYP2B6 of three SNPs (c.516G ≥ T, c.785A ≥ G and g.21563C ≥ T) genotypes were significantly associated with higher efavirenz concentrations.ConclusionsOur data indicate that the GAC‐CYP2B6 haplotype is associated with higher plasma efavirenz concentrations in HIV‐infected Thai adults.

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Section: Introductionmentioning

confidence: 99%

Pharmacogenetic markers of CYP2B6 associated with efavirenz plasma concentrations in HIV‐1 infected Thai adults

Sukasem

Cressey

Prapaithong

et al. 2012

Brit J Clinical Pharma

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“…Although rifampin resulted in a modest reduction in efavirenz plasma exposure in subjects as a whole, there was high variability in responses between subjects, suggesting that efavirenz dose adjustment with rifampin may need to be individualized. Body weight and genetic factors will be important covariates in dosing algorithms.Efavirenz is an essential component of preferred antiretroviral regimens in treatment of human immunodeficiency virus (HIV) infection in patients coinfected with tuberculosis (TB) (6,32,33). The standard adult dose of 600 mg daily is associated with considerable interindividual variability in plasma concentrations and clinical effects (10,28,38).…”

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confidence: 99%

“…Efavirenz is an essential component of preferred antiretroviral regimens in treatment of human immunodeficiency virus (HIV) infection in patients coinfected with tuberculosis (TB) (6,32,33). The standard adult dose of 600 mg daily is associated with considerable interindividual variability in plasma concentrations and clinical effects (10,28,38).…”

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confidence: 99%

“…While the clinical significance of the interactions between efavirenz and rifampin is not entirely understood, to offset the mean reduction of efavirenz exposure with rifampin, some experts have recommended increasing the efavirenz dose to 800 mg/day, especially when body weight is greater than 50 kg (6,33). An extensive review of published literature did not find adequate evidence to support a dose increase with rifampin coadministration because of current lack of understanding of the likelihood of under-or overdosing individuals (11).…”

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confidence: 99%

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Modest but Variable Effect of Rifampin on Steady-State Plasma Pharmacokinetics of Efavirenz in Healthy African-American and Caucasian Volunteers

Kwara

Tashima

Dumond

et al. 2011

Antimicrob Agents Chemother

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Efavirenz-based antiretroviral regimen is preferred during rifampin-containing tuberculosis therapy. However, current pharmacokinetic data are insufficient to guide optimized concurrent dosing. This study aimed to better characterize the effects of rifampin on efavirenz pharmacokinetics. Subjects were randomized to receive 600 mg efavirenz/day or 600 mg efavirenz with 600 mg rifampin/day for 8 days, with plasma samples collected for pharmacokinetic analysis over 24 h on day 8. Treatments were then crossed over after at least a 2-week washout period, and procedures were repeated. Efavirenz concentrations were determined by high-performance liquid chromatography (HPLC), and pharmacokinetic parameters were estimated by noncompartmental analysis. Efavirenz pharmacokinetic differences between treatment periods were evaluated by paired t test. The coefficients of variation in efavirenz plasma AUC 0-24 (area under the concentration-time curve from 0 to 24 h) were 50% and 56% in the absence and presence of rifampin, respectively. Of the 11 evaluable subjects (6 white, 5 black; 6 women, 5 men), the geometric mean AUC 0-24 ratio on/off rifampin (90% confidence interval) was 0.82 (0.72, 0.92), with individual AUC 0-24 ratios varying from 0.55 to 1.18. Five subjects had a 24-hour efavirenz concentration (C 24 ) of <1,000 ng/ml on rifampin. They were more likely to have received a lower dose in milligrams/kilogram of body weight and to have lower efavirenz AUC 0-24 values in the basal state. Although rifampin resulted in a modest reduction in efavirenz plasma exposure in subjects as a whole, there was high variability in responses between subjects, suggesting that efavirenz dose adjustment with rifampin may need to be individualized. Body weight and genetic factors will be important covariates in dosing algorithms.Efavirenz is an essential component of preferred antiretroviral regimens in treatment of human immunodeficiency virus (HIV) infection in patients coinfected with tuberculosis (TB) (6,32,33). The standard adult dose of 600 mg daily is associated with considerable interindividual variability in plasma concentrations and clinical effects (10,28,38). There is even greater variability in efavirenz concentrations during coadministration with rifampin or rifampin-containing TB therapy (2,13,29). Efavirenz is primarily metabolized by hepatic CYP2B6, with some contributions from CYP3A4/5 (42), CYP2A6 (30), and UGT2B7 enzymes (1). Rifampin was shown to be a potent inducer of CYP2B6 activity when bupropion was used as a probe of enzyme activity (22). Among healthy volunteers, rifampin caused 26% and 20% reductions in mean efavirenz area under the curve (AUC) and maximum concentration (C max ), respectively (2). Among HIV-TB-coinfected patients, mean reductions of 24% and 25% in efavirenz AUC and C max , respectively, were reported with rifampin coadministration. In the above-mentioned studies, some subjects had higher efavirenz plasma exposure with rifampin (compared with that when off rifampin), suggesting a lack of a signif...

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“…Nevertheless it is not intended to describe in detail how to meet these standards or to present detailed standard operating procedures (SOP). It aims to complement existing WHO and other international recommendations and guidelines [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

Section: Who Euro Laboratory Task Forcementioning

confidence: 99%

Recommended standards for modern tuberculosis laboratory services in Europe

Drobniewski¹,

Hoffner²,

Rüsch-Gerdes³

et al. 2006

Eur Respir J

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The principles underpinning these standards are that any tuberculosis laboratorybased diagnostic procedure should be performed by appropriately trained staff, working to standardised operating procedures in appropriately equipped and safe laboratories, against clear national and international proficiency and quality standards. Quality should be the pre-eminent criteria, not cost.The standards are technologically feasible, but initially may not be within the financial capacity of all laboratories. There is a requirement for government and international donors to adequately fund an appropriate safe infrastructure to enable staff to deliver accurate and timely results at whatever level of activity they are performing.There is a need for national reference laboratories to train a new cadre of mycobacterial laboratory experts. This will require the funding of appropriate individuals at these centres to train and assist in the implementation of good laboratory practice and evaluation to build sustainable capacity. Further operational research is needed to establish the optimal configuration of new technologies to determine isoniazid, rifampicin and second-line drug susceptibility in mycobacterial cultures and also, increasingly, directly on specimens.Improved integration of laboratory medicine as a core part of all tuberculosis programmes is needed to achieve and maximise the potential of new developments.

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BHIVA treatment guidelines for tuberculosis (TB)/HIV infection 2005

Cited by 62 publications

References 112 publications

Pharmacogenetic markers of CYP2B6 associated with efavirenz plasma concentrations in HIV‐1 infected Thai adults

Pharmacogenetic markers of CYP2B6 associated with efavirenz plasma concentrations in HIV‐1 infected Thai adults

Modest but Variable Effect of Rifampin on Steady-State Plasma Pharmacokinetics of Efavirenz in Healthy African-American and Caucasian Volunteers

Recommended standards for modern tuberculosis laboratory services in Europe

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