Treatment of childhood tuberculosis: caregivers' practices and perceptions in Cape Town, South Africa

Parents' Experiences and Perspectives Toward Tuberculosis Treatment Success Among Children in Malaysia: A Qualitative Study

Introduction: The trends of tuberculosis (TB) treatment success rate among children in Malaysia plateaued at 90% from 2014 to 2017. Malaysia sets a higher treatment success target of 95% to be achieved in line with an affordable, accessible, and holistic approach in managing TB among children. Objective: This study aims to explore the parents' experiences and perspectives toward achieving treatment success among children who were diagnosed with TB in two districts in Selangor state, Malaysia. Methods: The study was conducted using phenomenology study design via an in-depth interview of 15 mothers who were purposively sampled from the list of pediatric TB cases in the MyTB version 2.1 database in Klang and Petaling Districts of Selangor state. The R-based qualitative data analysis package of R version 0.2-8 was used to perform the thematic analysis. Results: Two main themes were identified from this study. The first theme was trust toward the healthcare services with the subthemes of acceptance, self-efficacy, holistic care, and perceived benefits. The second theme was the motivation to take or continue medication. The subthemes were support from family, healthcare workers' (HCWs') support, the convenience of healthcare services, community support, personal strength, and child's character. Conclusion: TB treatment success for children can be achieved when parents develop trust in healthcare services and have strong motivational factors to remain steadfast in achieving a successful treatment goal. Psychosocial support should be provided to the primary caregiver who faced any difficulty, while good relationships between parents and HCWs should be maintained. These results will inform the TB program managers to strengthen the holistic approach and identify the motivational factors among parents of children with TB disease.

Population Pharmacokinetics of Cycloserine and Pharmacokinetic/Pharmacodynamic Target Attainment in Multidrug-Resistant Tuberculosis Patients Dosed with Terizidone

Cycloserine is a WHO group B drug for the treatment of multidrug-resistant tuberculosis (TB). Pharmacokinetic/pharmacodynamic data for cycloserine when dosed as terizidone are sparse. The aim of this analysis was to describe the population pharmacokinetics of cycloserine when administered as terizidone and predict the doses of terizidone attaining cycloserine exposures associated with efficacy. The plasma cycloserine level was measured 2 to 6 weeks after treatment initiation in patients hospitalized for second-line tuberculosis treatment. The pretreatment MICs of cycloserine were determined for the clinical isolates. We enrolled 132 participants with rifampicin-resistant TB; 79 were HIV positive. The median pretreatment MIC was 16 mg/liter. A one-compartment disposition model with two clearance pathways, nonrenal (0.35 liters/h) and renal (0.43 liters/h), described cycloserine pharmacokinetics well. Nonrenal clearance and the volume of distribution were allometrically scaled using fat-free mass. Smoking increased nonrenal clearance by 41%. Simulations showed that with daily doses of terizidone (750 mg and 1,000 mg for patients weighing ≤45 kg and >45 kg, respectively), the probability of maintaining the plasma cycloserine concentration above the MIC for more than 30% of the dosing interval (30% T>MIC) (which is associated with a 1.0-log10-CFU/ml kill in vitro) exceeded 90% at MIC values of ≤16 mg/liter, but the proportion of patients achieving 100% T>MIC (which is associated with the prevention of resistance) was more than 90% only at MICs of ≤8 mg/liter. Based on a target derived in vitro, the WHO-recommended doses of terizidone are effective for cycloserine MICs of ≤8 mg/liter, and higher doses are required to prevent the development of resistance.

Impact of Food and Drink Administration Vehicles on Paediatric Formulation Performance Part 2: Dissolution of Montelukast Sodium and Mesalazine Formulations

Paediatric medicines are not always age-appropriate, causing problems with dosing, acceptability and adherence. The use of food and drinks as vehicles for medicine co-administration is common practice, yet the impact on drug bioavailability, safety and efficacy remains unaddressed. The aim of this study was to use in vitro dissolution testing, under infant simulating conditions, to evaluate the effect of co-administration with vehicles on the dissolution performance of two poorly soluble paediatric drugs. Dissolution studies of mesalazine and montelukast formulations were conducted with mini-paddle apparatus on a two-stage approach: simulated gastric fluid followed by addition of simulated intestinal fluid. The testing scenarios were designed to reflect daily administration practices: direct administration of formulation; formulation co-administered with food and drinks, both immediately after mixing and 4 h after mixing. Drug dissolution was significantly affected by medicine co-administration with vehicles, compared to the direct administration of formulation. Furthermore, differences were observed on drug dissolution when the formulations were mixed with different vehicles of the same subtype. The time between preparation and testing of the drug-vehicle mixture also impacted dissolution behaviour. Drug dissolution was shown to be significantly affected by the physicochemical properties and composition of the vehicles, drug solubility in each vehicle and drug/formulation characteristics. Ultimately, in this study, we show the potential of age-appropriate in vitro dissolution testing as a useful biopharmaceutical tool for estimating drug dissolution in conditions relevant to the paediatric population. The setup developed has potential to evaluate the impact of medicine co-administration with vehicles on paediatric formulation performance.

Impact of Food and Drink Administration Vehicles on Paediatric Formulation Performance: Part 1-Effects on Solubility of Poorly Soluble Drugs

Food and drinks are commonly used to facilitate administration of paediatric medicines to improve palatability and enhance patient compliance. However, the impact of this practice on drug solubility and on oral drug bioavailability is not usually studied. Based on recommended strategies for oral administration of paediatric medicines with food and drink vehicles, the aims of this study were (i) to measure the physicochemical properties of (soft) food and drink vehicles, commonly mixed with paediatric medicines prior to administration, and (ii) to assess the impact of the co-administered vehicles on the solubility of two poorly soluble paediatric drugs. Montelukast (sodium) and mesalazine were selected as the model compounds. Distinct differences were observed between the physicochemical properties (i.e. pH, surface tension, osmolality, viscosity and buffer capacity) and macronutrient composition (i.e. fat, sugar and protein content) of the different soft foods and drinks, not only among vehicle type but also within vehicles of the same subtype. Solubility studies of the two model compounds in selected drinks and soft foods resulted in considerably different drug solubility values in each vehicle. The solubility of the drugs was significantly affected by the vehicle physicochemical properties and macronutrient composition, with the solubility of montelukast being driven by the pH, fat and protein content of the vehicles and the solubility of mesalazine by vehicle osmolality, viscosity and sugar content. This vehicle-dependent impact on drug solubility could compromise its bioavailability, and ultimately affect the safety and/or efficacy of the drug and should be taken into consideration during paediatric product development.

Co-administration of Paediatric Medicines with Food and Drinks in the Context of Their Physicochemical Properties-a Global Perspective on Practices and Recommendations

Medicine co-administration with food or drink vehicles is a common administration practice in paediatrics. The aims of this review were (i) to describe the current recommended strategies for co-administration of paediatric medicines with food and drinks (vehicles); (ii) to compare current administration recommendations from different countries; and (iii) to obtain a global perspective on the rationale behind the choice of recommended vehicle, in the context of the physicochemical properties of the drug and formulation. This study used a defined search strategy on the practices of paediatric medicine co-administration with vehicles, recommended in a commonly used paediatric and neonatal handbook, in addition to the information previously gathered from UK formularies. Logistic regression analysis was performed to further understand the biopharmaceutical basis of the choice of recommended vehicle for medicine co-administration. Differences were identified in the type of vehicles globally recommended for medicine co-administration. Ultimately, a statistical model was developed which provided an understanding on which vehicle is recommended for use with drugs/formulations, with basis on their biopharmaceutical properties. Overall, this review highlights the areas where further information is needed to support standardised procedures and guide the recommendation of age-appropriate and acceptable vehicles for use in the co-administration of paediatric medicines. Unified requirements are needed for harmonisation of the practice of medicine co-administration with vehicles. In vitro and/or in silico tools should be developed to evaluate the potential clinical outcomes of this practice during paediatric drug development.

Effect of tablet crushing on drug exposure in the treatment of multidrug-resistant tuberculosis

SETTING: Treatment outcomes in multidrug-resistant tuberculosis (MDR-TB) are poor. Due to drug toxicity and a long treatment duration, approximately half of patients are treated successfully. Medication is often crushed for patients who have difficulty swallowing whole tablets. Whether crushing tablets affects drug exposure in MDR-TB treatment is not known.OBJECTIVE AND DESIGN: We performed a sequential pharmacokinetic study in patients aged >18 years on MDR-TB treatment at two hospitals in Cape Town, South Africa. We compared the bioavailability of pyrazinamide, moxifloxacin, isoniazid (INH), ethambutol and terizidone when the tablets were crushed and mixed with water before administration vs. swallowed whole. We sampled blood at six time points over 10 h under each condition separated by 2 weeks. Non-compartmental analysis was used to derive the key pharmacokinetic measurements.RESULTS: Twenty participants completed the study: 15 were men, and the median age was 31.5 years. There was a 42% reduction in the area under the curve AUC0-10 of INH when the tablets were crushed compared with whole tablets (geometric mean ratio 58%; 90%CI 47-73). Crushing tablets of pyrazinamide, moxifloxacin, ethambutol and terizidone did not affect the bioavailability significantly.CONCLUSION: We recommend that crushing of INH tablets in the MDR-TB treatment regimen be avoided. Paediatric INH formulations may be a viable alternative if the crushing of INH tablets is indicated.

A survey of caregivers of Nigerian children less than 6 years of age to determine the experience and perception of acceptability of oral solid dosage forms

OBJECTIVES

The World Health Organization (WHO) recommends flexible solid oral dosage forms such as dispersible tablet as the preferred formulation for (young) children, especially in developing/low- and middle-income countries, LMIC. The aim of this study was to assess experience, perceptions of acceptability, and formulation preferences, among 10 oral dosage forms for young children in a sample of end-users in Nigeria as an exemplar LMIC.

METHODS

Using a semi-structured and validated questionnaire, 148 caregivers were surveyed. Acceptability was assessed by level of liking using a 3-point Likert scale and ease of administration. Preference was assessed from participants' dosage form of choice. Oral dosage forms assessed were those mentioned in the British National Formulary for children, 2013.

RESULTS

The formulation perceived as the most acceptable was the chewable/suckable tablet. However, preference was for liquids. Specifically with the dispersible tablet, whilst 89% (n=111) of caregivers of young children found it easy-to-administer, only 50% of children liked it.

CONCLUSION

There is a gap between the proposal of dispersible tablet as the preferred dosage form for young children and caregivers' perceptions of acceptability and preference. Educational strategies to increase acceptability of dispersible tablets as the preferred formulation for young children would be required.

Recommended strategies for the oral administration of paediatric medicines with food and drinks in the context of their biopharmaceutical properties: a review

OBJECTIVES

This review focuses on the recommended strategies for the oral administration of paediatric medicines with food in the context of their biopharmaceutical properties.

KEY FINDINGS

Acceptability of oral medicines in young patients is more challenging than in adult patients. Mixing oral dosage forms with foods and drinks is sometimes suggested to administer a specific dose and enhance compliance in the paediatric population. In this review, the strategies for the co-administration of paediatric medicines with food and drinks are discussed. Current administration practices as reported by healthcare professionals and parents/carers are compared with the relevant guidelines. Differences in the type of vehicles recommended to be used and actually used in current practice were identified. Correlations of the type of food recommended, the type of formulation and the drug's biopharmaceutical classification system (BCS) class were performed and revealed that recommendations should be made on a case-by-case basis.

SUMMARY

The propensity for physiochemical or bioavailability changes that may occur from the co-administration of medicines with food and drinks in the paediatric population should be considered, and harmonisation of the recommended administration strategies is needed.