rifampin and Malnutrition

Determining the optimal dosages of isoniazid, rifampicin, pyrazinamide and ethambutol in children is necessary to obtain therapeutic serum concentrations of these drugs. Revised dosages have improved the exposure of 1st line anti-tubercular drugs to some extent; there is still scope for modification of the dosages to achieve exposures which can lead to favourable outcome of the disease. High dose of rifampicin is being investigated in clinical trials in adults with some benefit; studies are required in children. Inter-individual pharmacokinetic variability and the effect of age, nutritional status, Human immunodeficiency virus (HIV) infection, acetylator genotype may need to be accounted for in striving for the dosages best suited for an individual.

Topics: Age Factors; Antitubercular Agents; Child; Drug Overdose; Ethambutol; Food; Genotype; HIV Infections; Humans; Isoniazid; Malnutrition; Nutritional Status; Polymorphism, Genetic; Pyrazinamide; Rifampin; Treatment Outcome; Tuberculosis

Nutritional status may have a profound impact on the pharmacokinetics of drugs, yet only few data are available for tuberculosis (TB) drugs. As malnutrition occurs frequently among TB patients, we assessed the effect of malnutrition on the steady-state pharmacokinetics of total and protein-unbound rifampin during the intensive phase of TB treatment. In a descriptive pharmacokinetic study in Bandung, Indonesia, patients received a fixed standard rifampin dose of 450 mg once daily during the intensive phase of TB treatment. A full pharmacokinetic curve for rifampin was recorded, and total and unbound concentrations of rifampin were analyzed in all samples. Rifampin pharmacokinetic parameters were compared between severely malnourished (BMI of <16.0 kg/m(2)), malnourished (BMI of <18.5 kg/m(2)), and well-nourished (BMI of ≥18.5 kg/m(2)) individuals. No difference in total and protein-unbound pharmacokinetic parameters between severely malnourished (n = 7), malnourished (n = 11), and well-nourished (n = 25) patients could be demonstrated. In addition, no significant correlation between BMI and exposure (area under the concentration-time curve from 0 to 24 h [AUC0-24] and maximum concentration of drug in serum [Cmax]) was found. Females had significantly higher total AUC0-24 (geometric mean, 59.2 versus 48.2 h · mg/liter; P = 0.02) and higher unbound AUC0-24 (geometric mean, 6.2 versus 4.8 h · mg/liter; P = 0.02) than males. Overall, a marked 2-fold interindividual variation in the free fraction was observed (7.6 to 15.0%; n = 36). Nutritional status and BMI do not appear to have a major effect on total and protein-unbound pharmacokinetic parameters of rifampin in Indonesian subjects. The large interindividual variability in the free fraction of rifampin suggests that protein-unbound rather than total rifampin concentrations should preferably be used to study exposure-response relationships.

Topics: Adolescent; Adult; Antitubercular Agents; Body Mass Index; Drug Administration Schedule; Female; Humans; Indonesia; Male; Malnutrition; Middle Aged; Rifampin; Tuberculosis; Young Adult

We compared the nutritional status of individuals with human immunodeficiency virus (HIV) infection alone, individuals with HIV infection and tuberculosis (after completion of antituberculosis treatment), and HIV-negative individuals and found that malnutrition, anemia, and hypoalbuminemia were most pronounced among HIV-positive patients with tuberculosis. Weight loss was associated with loss of fat in female patients and with loss of body cell mass in male patients.

Topics: Adult; AIDS-Related Opportunistic Infections; Anemia; Antitubercular Agents; Body Composition; Drug Therapy, Combination; Ethambutol; HIV Infections; HIV Seronegativity; Humans; Hypoalbuminemia; India; Isoniazid; Malnutrition; Nutritional Status; Pyrazinamide; Rifampin; Treatment Outcome; Tuberculosis, Pulmonary

In 2010, the World Health Organization (WHO) revised the paediatric dosages of anti-tuberculosis drugs, increasing rifampicin to 15 mg/kg, isoniazid to 10 mg/kg and pyrazinamide to 35 mg/kg. We assessed treatment outcomes, safety and adherence among children treated with the new recommended dosages.. Prospective cohort of children started on anti-tuberculosis treatment in Uganda with 12 months of follow-up, including alanine aminotransferase (ALT) monitoring. Treatment intake was observed.. Of 144 treated children, 81 were male (56.3%), 106 (73.6%) were aged <5 years, 30 (22%) had moderate to severe malnutrition and 48 (33.3%) had human immunodeficiency virus infection. Treatment outcomes were as follows: 117 (81.3%) successes, 3 (2.1%) failures, 4 (2.8%) lost to follow-up, 19 (13.2%) deaths and 1 (0.7%) transferred out. There was no relapse. Severe malnutrition (adjusted hazard ratio 8.76, 95% confidence interval [CI] 1.59-48.25) was the only predictor of death. Two serious adverse events were attributed to treatment: one case of increased ALT and one with peripheral neuropathy. Median ALT values at baseline and at weeks 2, 4 and 8 were respectively 24 (interquartile range [IQR] 16-39), 26 (IQR 18-38), 28 (IQR 21-40) and 27 (IQR 19-38) international units/l. Treatment adherence was above 85% on all visits.. We confirm the good tolerability of and adherence to the new treatment recommendations. The increased risk of fatal outcome among severely malnourished children requires attention.

Topics: Antitubercular Agents; Child, Preschool; Cohort Studies; Female; HIV Infections; Humans; Infant; Infant, Newborn; Isoniazid; Male; Malnutrition; Patient Compliance; Practice Guidelines as Topic; Prospective Studies; Pyrazinamide; Rifampin; Treatment Outcome; Tuberculosis, Pulmonary; Uganda; World Health Organization

The World Health Organization (WHO) recently issued revised first-line antituberculosis (anti-TB) drug dose recommendations for children, with dose increases proposed for each drug. No pharmacokinetic data are available from South American children. We examined the need for implementation of these revised guidelines in Venezuela.. Plasma isoniazid, rifampicin, pyrazinamide and ethambutol concentrations were assessed prior to and at 2, 4 and 8 h after intake of TB drugs by 30 TB patients aged 1-15 years. The effects of dose in mg/kg, age, sex, body weight, malnutrition and acetylator phenotype on maximum plasma drug concentrations (Cmax) and exposure (AUC0-24) were determined.. 25 patients (83%) had an isoniazid Cmax below 3 mg/l and 23 patients (77%) had a rifampicin Cmax below 8 mg/l. One patient (3%) had a pyrazinamide Cmax below 20 mg/l. The low number of patients on ethambutol (n = 5) precluded firm conclusions. Cmax and AUC0-24 of all four drugs were significantly and positively correlated with age and body weight. Patients aged 1-4 years had significantly lower Cmax and AUC0-24 values for isoniazid and rifampicin and a trend to lower values for pyrazinamide compared to those aged 5-15 years. The geometric mean AUC0-24 for isoniazid was much lower in fast acetylators than in slow acetylators (5.2 vs. 12.0, P < 0.01).. We provide supportive evidence for the implementation of the revised WHO pediatric TB drug dose recommendations in Venezuela. Follow-up studies are needed to describe the corresponding plasma levels that are achieved by the recommended increased doses of TB drugs.

Topics: Acetyltransferases; Adolescent; Age Factors; Antitubercular Agents; Area Under Curve; Biological Availability; Child; Child, Preschool; Dose-Response Relationship, Drug; Ethambutol; Female; Humans; Infant; Isoniazid; Least-Squares Analysis; Male; Malnutrition; Polymorphism, Genetic; Practice Guidelines as Topic; Pyrazinamide; Rifampin; Tuberculosis; Venezuela; World Health Organization