Caution when treating tuberculosis in malnourished children

Influence of Malnutrition on the Pharmacokinetics of Drugs Used in the Treatment of Poverty-Related Diseases: A Systematic Review

Background

Patients affected by poverty-related infectious diseases (PRDs) are disproportionally affected by malnutrition. To optimize treatment of patients affected by PRDs, we aimed to assess the influence of malnutrition associated with PRDs on drug pharmacokinetics, by way of a systematic review.

Methods

A systematic review was performed on the effects of malnourishment on the pharmacokinetics of drugs to treat PRDs, including HIV, tuberculosis, malaria, and neglected tropical diseases.

Results

In 21/29 PRD drugs included in this review, pharmacokinetics were affected by malnutrition. Effects were heterogeneous, but trends were observed for specific classes of drugs and different types and degrees of malnutrition. Bioavailability of lumefantrine, sulfadoxine, pyrimethamine, lopinavir, and efavirenz was decreased in severely malnourished patients, but increased for the P-glycoprotein substrates abacavir, saquinavir, nevirapine, and ivermectin. Distribution volume was decreased for the lipophilic drugs isoniazid, chloroquine, and nevirapine, and the α1-acid glycoprotein-bound drugs quinine, rifabutin, and saquinavir. Distribution volume was increased for the hydrophilic drug streptomycin and the albumin-bound drugs rifampicin, lopinavir, and efavirenz. Drug elimination was decreased for isoniazid, chloroquine, quinine, zidovudine, saquinavir, and streptomycin, but increased for the albumin-bound drugs quinine, chloroquine, rifampicin, lopinavir, efavirenz, and ethambutol. Clinically relevant effects were mainly observed in severely malnourished and kwashiorkor patients.

Conclusions

Malnutrition-related effects on pharmacokinetics potentially affect treatment response, particularly for severe malnutrition or kwashiorkor. However, pharmacokinetic knowledge is lacking for specific populations, especially patients with neglected tropical diseases and severe malnutrition. To optimize treatment in these neglected subpopulations, adequate pharmacokinetic studies are needed, including severely malnourished or kwashiorkor patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40262-021-01031-z.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Drug Treatment of Non-Tuberculous Mycobacteria in Cystic Fibrosis

Non-tuberculous mycobacteria (NTM) are an emerging group of pulmonary infectious pathogens of increasing importance to the management of patients with cystic fibrosis (CF). NTM include slow-growing mycobacteria such as Mycobacterium avium complex (MAC) and rapidly growing mycobacteria such as Mycobacterium abscessus. The incidence of NTM in the CF population is increasing and infection contributes to significant morbidity to the patient and costs to the health system. Treating M. abscessus requires the combination of multiple costly antibiotics for months, with potentially significant toxicity associated with treatment. Although international guidelines for the treatment of NTM infection in CF are available, there are a lack of robust pharmacokinetic studies in CF patients to inform dosing and drug choice. This paper aims to outline the pharmacokinetic and pharmacodynamic factors informing the optimal treatment of NTM infections in CF.

Effect of malnutrition on the pharmacokinetics of anti-TB drugs in Ghanaian children

BACKGROUND: Anti-TB drugs dosing based on weight alone may contribute to suboptimal drug concentrations and poor treatment outcomes in malnourished children. We examined the effect of malnutrition on the pharmacokinetics (PK) of first-line anti-TB drugs in children.METHODS: Drug concentrations were measured in Ghanaian children during the intensive phase of TB treatment. Weight-for-age (WFA), height-for-age (HFA), weight-for-height (WFH) and body mass index-for-age (BFA) were calculated and children with Z-scores < -2 SD (standard deviations) were considered as having malnutrition. PK differences of anti-TB drugs were compared by nutritional status.RESULTS: Of 100 participants, 24/48 (50.0%) of those younger than 5 years had wasting, 58/86 (67.4%) were underweight, and 56/99 (56.6%) had stunting; 22/51 (43.1%) children aged ≥5 years had low BFA. Children with stunting were more likely than controls to have lower mean peak concentration (Cmax) and area under the curve (AUC0-8h) of rifampin (RIF) and pyrazinamide (PZA), as well as a higher frequency of Cmax below the normal range. Wasting and underweight were associated with lower mean ethambutol (EMB) Cmax and AUC0-8h.CONCLUSIONS: The current WHO-recommended dosages were associated with lower plasma exposure of RIF, PZA and EMB in children with stunting, wasting and underweight. Anti-TB drugs dosing models for children may need to include height.

In vitro, in vivo and in silico rationale for the muscle loss due to therapeutic drugs used in the treatment of Mycobacterium tuberculosis infection

Tuberculosis globally affects millions of people every year and is responsible for high rates of mortality and morbidity in tropical countries like India. The treatment of tuberculosis involves using the first line of drugs especially Isoniazid, Pyrazinamide, Streptomycin, Ethambutol and Rifampicin for treatment under the DOTS (Directly Observed Treatment Shots) regime which can last up to minimum of six months. These drugs although widely used against Mycobacterium tuberculosis has given rise to multi drug resistant (MDR) tuberculosis strain. It has been observed widely that prolonged drug treatment for tuberculosis patient has rendered several side effects that include increasing muscle wasting and malnutrition. In our study, we have investigated the role of these major tuberculosis drugs namely Rifampicin, Streptomycin, Isoniazid, Pyrazinamide, and Ethambutol on actin polymerization which are famously known to be a central player in the sarcomere region of the muscle in human body. For in vitro studies, we have used biophysical approaches such as 90° scattering assay (RLS), size exclusion chromatography (SEC), Dynamic light scattering (DLS), Circular dichroism spectroscopy (CD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), kinetic analysis to understand the time taken to break down effect of above mentioned drugs on actin disruption. In vivo analysis was carried out on yeast Δend3 mutants which are rich in F-actin filaments in order to understand the effect of the aforementioned drugs in rendering the muscle wasting phenomenon in tuberculosis. Furthermore, we also carried out in silico analysis to understand the probable modes of binding of these drugs on actin filaments.Communicated by Ramaswamy H. Sarma.

Impact of negative tuberculin skin test on growth among disadvantaged Bangladeshi children

Millions of children are suffering from tuberculosis (TB) worldwide and often end-up with fatal outcome especially in resource-poor settings. Tuberculin skin test (TST) is a conventionally used diagnostic test, less sensitive but highly specific for the diagnosis of clinical TB especially in undernourished children. However, we do not have any data on the role of TST positivity among the children who received nutritional intervention. Our aim was to examine the growth differences between TST-positive and TST-negative undernourished children aged 12 to 18 months who received nutritional intervention prospectively for 90 feeding days. Our further aim was to explore the determinants of TST positivity at enrollment. TB screening as one of the secondary causes of malnutrition was performed on 243 stunted [length for age Z score (LAZ) <-2 standard deviations] or at-risk of stunting (LAZ score between <-1 and -2 standard deviations) children in a community-based intervention study designed to improve their growth parameters. Differences of growth between TST-positives (n = 29) and TST-negatives (n = 214) were compared using paired samples t-test and multivariable linear regression from anthropometric data collected before and after nutritional intervention. Multivariable logistic regression was used to find out possible predictors of TST positivity using baseline sociodemographic data. Of the 243 children screened, 29 (11.9%) were TST-positive and 11 (4.5%) had clinically diagnosed pulmonary TB. Statistically significant improvement of LAZ and weight for age Z-score (WAZ) were observed among the TST-negative participants at the end of intervention period (p = 0.03 for LAZ and p = 0.01 for WAZ). However, we did not find any association between TST status and response to nutritional intervention in our multivariable linear regression models. Our study findings demonstrated a positive impact of nutritional intervention on growth parameters among TST-negative participants.

Incidence Rates for Tuberculosis Among HIV Infected Patients in Northern Tanzania

Background: HIV and tuberculosis (TB) are leading infectious diseases, with a high risk of co-infection. The risk of TB in people living with HIV (PLHIV) is high soon after sero-conversion and increases as the CD4 counts are depleted.

Methodology: We used routinely collected data from Care and Treatment Clinics (CTCs) in three regions in northern Tanzania. All PLHIV attending CTCs between January 2012 to December 2017 were included in the analysis. TB incidence was defined as cases started on anti-TB medications divided by the person-years of follow-up. Poisson regression with frailty models were used to determine incidence rate ratios (IRR) and 95% confidence intervals (95% CI) for predictors of TB incidences among HIV positive patients.

Results: Among 78,748 PLHIV, 405 patients developed TB over 195,296 person-years of follow-up, giving an overall TB incidence rate of 2.08 per 1,000 person-years. There was an increased risk of TB incidence, 3.35 per 1,000 person-years, in hospitals compared to lower level health facilities. Compared to CD4 counts of <350 cells/μl, a high CD4 count was associated with lower TB incidence, 81% lower for a CD4 count of 350–500 cells/μl (IRR 0.19, 95% CI 0.04–0.08) and 85% lower for those with a CD4 count above 500 cells/μl (IRR 0.15, 95% CI 0.04–0.64). Independently, those taking ART had 66% lower TB incidences (IRR 0.34, 95% CI 0.15–0.79) compared to those not taking ART. Poor nutritional status and CTC enrollment between 2008 and 2012 were associated with higher TB incidences IRR 9.27 (95% CI 2.15–39.95) and IRR 2.97 (95% CI 1.05–8.43), respectively.

Discussion: There has been a decline in TB incidence since 2012, with exception of the year 2017 whereby there was higher TB incidence probably due to better diagnosis of TB following a national initiative. Among HIV positive patients attending CTCs, poor nutritional status, low CD4 counts and not taking ART treatment were associated with higher TB incidence, highlighting the need to get PLHIV on treatment early, and the need for close monitoring of CD4 counts. Data from routinely collected and available health services can be used to provide evidence of the epidemiological risk of TB.