2One-third of the world population is infected with Mycobacterium tuberculosis (MTB) and hence at risk of developing active tuberculosis (TB). Each year, 8.8 million patients are newly diagnosed with active TB and 1.6 million patients die of TB. The rapid spread of the human immunodeficiency virus (HIV) has fueled the TB epidemic, especially in sub-Saharan Africa, where 28% of TB patients are HIV positive (176). The current first-line treatment for TB is a multidrug regimen consisting of rifampin, isoniazid, pyrazinamide, and ethambutol (RHZE). It must be taken for at least 6 months to achieve high cure rates (more than 95% in experimental settings). PROBLEMS WITH CURRENT TUBERCULOSIS TREATMENTThere are several major problems associated with the currently available TB treatment. First, the duration and complexity of treatment result in nonadherence to treatment. This leads to suboptimal response (failure and relapse), the emergence of resistance, and continuous spread of the disease (168). Second, adverse events in response to anti-TB drugs are common and contribute to the problem of nonadherence (19,168). Third, the increasing incidence of multidrug-resistant (MDR; resistance to at least rifampin and isoniazid) and extensively drug-resistant (XDR; MDR resistance plus resistance to a fluoroquinolone and an aminoglycoside) TB is a serious concern. Resistant TB occurs in the presence of partially suppressive drug concentrations that enable replication of bacteria, the formation of mutants, and overgrowth of wild-type strains by mutants (selective pressure) (175). The prevalence of MDR TB in new TB cases ranged from 0% in some Western European countries to more than 22% in Azerbaijan (2002 to 2007 survey); 14 of 72 participating countries reported an MDR TB prevalence of more than 5% (177). Second-line drugs for drug-resistant TB are not available everywhere and are less effective, more toxic, and require longer use than first-line drugs (61). Fourth, coinfection of TB and HIV is a problem by itself. Combined treatment of TB and HIV involves a high pill count with associated adherence problems, overlapping toxicity profiles of the antiretroviral and anti-TB drugs, drug interactions between rifampin and the antiretroviral protease inhibitors, and the risk of immune reconstitution syndrome (104). Fifth, prophylactic therapy of latent TB (TB infection without symptoms) with isoniazid is also associated with problems of nonadherence (180). Attempts to shorten treatment with alternative drugs resulted in severe adverse events (64,150,155).The World Health Organization (WHO) has developed the directly observed therapy short course (DOTS) strategy to optimize response and adherence to TB treatment. However, DOTS is labor-intensive and expensive. It causes a high burden on public health programs, especially in developing countries with limited human resources (49). In addition, TB diagnosis in the DOTS strategy is based on sputum microscopy, rather than sputum culture (173). Only advanced pulmonary TB is detected by sputum...

East Africa has a high tuberculosis (TB) incidence and mortality, yet there are very limited data on exposure to TB drugs in patients from this region. We therefore determined the pharmacokinetic characteristics of first-line TB drugs in Tanzanian patients using intensive pharmacokinetic sampling. In 20 adult TB patients, plasma concentrations were determined just before and at 1, 2, 3, 4, 6, 8, 10, and 24 h after observed drug intake with food to estimate the areas under the curve from 0 to 24 h (AUC 0 -24 ) and peak plasma concentrations (C max ) of isoniazid, rifampin, pyrazinamide, and ethambutol. Acetylator status for isoniazid was assessed phenotypically using the isoniazid elimination half-life and the acetylisoniazid/isoniazid metabolic ratio at 3 h postdose. The geometric mean AUC 0 -24 s were as follows: isoniazid, 11.0 h · mg/liter; rifampin, 39.9 h · mg/liter; pyrazinamide, 344 h · mg/liter; and ethambutol, 20.2 h · mg/liter. The C max was below the reference range for isoniazid in 10/19 patients and for rifampin in 7/20 patients. In none of the patients were the C max s for pyrazinamide and ethambutol below the reference range. Elimination half-life and metabolic ratio of isoniazid gave discordant phenotyping results in only 2/19 patients. A substantial proportion of patients had an isoniazid and/or rifampin C max below the reference range. Intake of TB drugs with food may partly explain these low drug levels, but such a drug intake reflects common practice. The finding of low TB drug concentrations is concerning because low concentrations have been associated with worse treatment outcome in several other studies.T he pharmacokinetic properties of tuberculosis (TB) drugs are well described, especially in Caucasian populations (1, 2). Pharmacokinetic data from East Africa are limited, especially data that are based on intensive pharmacokinetic sampling during the full dosing interval. Such intensive pharmacokinetic sampling enables an accurate assessment of the total exposure to TB drugs (area under the time-versus-plasma concentration curve from 0 to 24 h [AUC 0 -24 ]) and the peak plasma concentration (C max ) in individual patients. Large interpatient variability in these key pharmacokinetic parameters of TB drugs generally exists (1). As a result, a proportion of patients achieve drug concentrations that are below the reference range for TB drugs. Several studies have shown that such lower exposures to TB drugs are associated with a suboptimal response (3-8) A recent study showed that pharmacokinetic variability to just a single drug in the multidrug TB drug regimen is associated with treatment failure and acquired drug resistance (9, 10).On the other hand, unduly high exposures may cause toxicity and interruption of TB treatment. It is therefore important to have more knowledge on the pharmacokinetic properties of TB treatment in populations from East Africa, as a high TB incidence and a high TB mortality are found in this region (11). HIV infection (12-14) and malnutrition (15) have been associ...

BackgroundTo design effective, tailored interventions to support antiretroviral therapy (ART) adherence, a thorough understanding of the barriers and facilitators of ART adherence is required. Factors at the individual and interpersonal level, ART treatment characteristics and health care factors have been proposed as important adherence determinants.MethodsTo identify the most relevant determinants of adherence in northern Tanzania, in-depth interviews were carried out with 61 treatment-experienced patients from four different clinics. The interviews were ad-verbatim transcribed and recurrent themes were coded.ResultsCoding results showed that the majority of patients had basic understanding of adherence, but also revealed misconceptions about taking medication after alcohol use. Adherence motivating beliefs were the perception of improved health and the desire to live like others, as well as the desire to be a good parent. A de-motivating belief was that stopping ART after being prayed for was an act of faith. Facilitators of adherence were support from friends and family, and assistance of home based care (HBC) providers. Important barriers to ART adherence were the use of alcohol, unavailability of food, stigma and disclosure concerns, and the clinics dispensing too few pills. Strategies recommended by the patients to improve adherence included better Care and Treatment Centre (CTC) services, recruitment of patients to become Home Based Care ( HBC) providers, and addressing the problem of stigma through education.ConclusionThis study underscores the importance of designing tailored, patient-centered adherence interventions to address challenges at the patient, family, community and health care level.

In a multiple-dose-ranging trial, we previously evaluated higher doses of rifampin in patients for 2 weeks. The objectives of the current study were to administer higher doses of rifampin for a longer period to compare the pharmacokinetics, safety/tolerability, and bacteriological activity of such regimens. In a double-blind, randomized, placebo-controlled, phase II clinical trial, 150 Tanzanian patients with tuberculosis (TB) were randomized to receive either 600 mg (approximately 10 mg/kg of body weight), 900 mg, or 1,200 mg rifampin combined with standard doses of isoniazid, pyrazinamide, and ethambutol administered daily for 2 months. Intensive pharmacokinetic sampling occurred in 63 patients after 6 weeks of treatment, and safety/tolerability was assessed. The bacteriological response was assessed by culture conversion in liquid and solid media. Geometric mean total exposures (area under the concentration-versus-time curve up to 24 h after the dose) were 24.6, 50.8, and 76.1 mg · h/liter in the 600-mg, 900-mg, and 1,200-mg groups, respectively, reflecting a nonlinear increase in exposure with the dose ( < 0.001). Grade 3 adverse events occurred in only 2 patients in the 600-mg arm, 4 patients in the 900-mg arm, and 5 patients in the 1,200-mg arm. No significant differences in the bacteriological response were observed. Higher daily doses of rifampin (900 and 1,200 mg) resulted in a more than proportional increase in rifampin exposure in plasma and were safe and well tolerated when combined with other first-line anti-TB drugs for 2 months, but they did not result in improved bacteriological responses in patients with pulmonary TB. These findings have warranted evaluation of even higher doses of rifampin in follow-up trials. (This study has been registered at ClinicalTrials.gov under identifier NCT00760149.).