Do difficulties in swallowing medication impede the use of hydroxyurea in children?

Assessing multilevel barriers to hydroxyurea adherence in youth with sickle cell disease using pharmacy-based refill records

BACKGROUND

Suboptimal medication adherence is common across youth with chronic health conditions and may contribute to health disparities and adverse health outcomes, especially in underserved communities.

METHODS

Using pharmacy prescription records and guided by the World Health Organization Multidimensional Adherence Model, we examined patient-, treatment-, and health system-related factors that may affect hydroxyurea adherence in 72 youth with sickle cell disease (SCD), 10-18 years who had participated in the multisite "Hydroxyurea Adherence for Personal Best in SCD" (HABIT) feasibility (6 months) and efficacy (12 months) trials. Pharmacy data were collected from the year prior to study entry through the duration of each trial. We also examined hydroxyurea dose at baseline, prescribing patterns (hydroxyurea formulation and dose prescribed), quantity of hydroxyurea dispensed, and number of daily capsules/tablets prescribed. Data were analyzed using descriptive statistics.

RESULTS

On average, youth were prescribed 1095 ± 402 mg hydroxyurea per day, requiring ingestion of 3 or more capsules for 39.4% of youth. Frequently identified potential barriers were complex medication regimens in which dose of hydroxyurea differed by day of week (47.2%); receipt of an inadequate (< 30 days) supply of hydroxyurea from the pharmacy ≥ 3 times during record collection period (29.2%); and prescription of hydroxyurea suspension suggesting problems swallowing capsules (22.2%). In this sample, most youth were exclusively prescribed 500 mg capsules (62.5%), which was associated with complex medication regimens (RR 3.0, 95% CI 1.4-6.7). Potential barriers were common, occurred at all levels and are potentially modifiable with targeted interventions at the treatment- and health system-related levels.

Paediatric medicine issues and gaps from healthcare workers point of view: survey results and a narrative review from the global accelerator for paediatric formulations project

The WHO Model List of Essential Medicines for Children (EMLc) has not been systematically revised in the last few years. We conducted a survey addressed to healthcare professionals prescribing, preparing, or administering medicines to children and a narrative review to identify problematic paediatric formulations or missing medicines in all therapeutic fields to inform the review of the EMLc in 2023. A total of 285 physicians (63%), 28 nurses (6%) and 142 pharmacists (31%), mostly working in the hospital setting, reported at least one problematic medicine. 290 medicines were reported as missing (completely or the child-appropriate formulation). The top three most mentioned were ciprofloxacin together with phenobarbital and omeprazole. 387 medicines were reported as problematic (34% were oral liquid formulations, 34% tablets, 18% parenteral preparations. Mostly of the products were antibacterials (27%), cardiovascular medicines (11%) and antivirals (11%). The obtained responses show the perspective of healthcare workers working around the world, particularly in the European region (25%), in the African region (24%), and in the Region of the Americas (19%), with limited representation from Northern Africa and the Middle East. Our results need to be analysed with the outputs of other ongoing works before specific products can enter the WHO-hosted Global Accelerator for Paediatric formulations network prioritisation process. Efforts to develop appropriate formulations for children should be accelerated so that the uncertainties associated with off-label drug preparation and use are minimised, and therapeutic benefits are optimised.

Impact of Hydroxyurea Starting Dose on Pain Outcomes in Patients with Sickle Cell Disease

In patients with sickle cell disease, hydroxyurea decreases the number of pain crises experienced. This study aimed to evaluate the difference in pain outcomes between patients started on a guideline concordant, weight-based starting dose of at least 15 mg/kg/day of hydroxyurea and those not. The first prescription of hydroxyurea was the baseline date, follow-up was a visit 60-120 days after baseline. The primary outcome was the change in opioid prescribing between baseline and follow-up. 138 patients met inclusion criteria; of these, 55 were started on a guideline concordant dose of hydroxyurea. Greater white blood cell count (9.5 vs 12.0; p < 0.01) was statistically associated with subtherapeutic dosing. Greater actual body weight (68.0 vs 72.1 kg; p = 0.16) also appeared higher in the non-guideline concordant group. No statistically significant difference in opioid prescribing was observed between those started on a guideline concordant dose of hydroxyurea and those who were not. In the guideline concordant starting dose group, 42% had a reduction in pain scores at first follow up, compared to 35% with a non-guideline recommended starting dose. (p = 0.41). While this difference is in the direction that would be expected based on the guidelines, the difference does not appear to be clinically meaningful.

Stability evaluation of compounded hydroxyurea 100 mg/mL oral liquids using a novel analytical method involving chemical derivatization

This study assessed the stability of six extemporaneously compounded hydroxyurea oral liquids stored at room temperature. Hydroxyurea oral liquids (100 mg/mL) were prepared using three different mixing methods (mortar, mixer or QuartetRx) from either bulk powder, capsule content, or whole capsules. Two brands of capsules were tested in this study. All formulations were stored at room temperature (25°C / 60% RH) in amber plastic bottles for 90 days and amber plastic syringes for 14 days. Physical stability was assessed visually, while chemical stability was evaluated using a stability-indicating high-performance liquid chromatography method. Chemical derivatization with xanthydrol allowed the retention of hydroxyurea on a reverse-phase column. At least 93.9% and 97.0% of the initial concentration of hydroxyurea remained after 90 days in bottles and 14 days in syringes, respectively. There were no visual changes in formulations over the study period. Changes in pH up to 1.6 units were observed after 90 days of storage and were explained most likely by an ammonium generating degradation pathway. Ammonium was quantified and remained within safe levels in each HU 100 mg/mL oral preparations. Hydroxyurea oral liquids were all stable for 90 days in amber plastic bottles and 14 days in amber plastic syringes.

A Systematic Review of Medication Adherence Interventions in Pediatric Sickle Cell Disease

Objective

Adherence to medication regimens is of critical importance in sickle cell disease (SCD). Most notably, data indicate that hydroxyurea, penicillin, and iron chelators increase life expectancy and decrease comorbid medical problems (e.g., strokes). However, average pediatric SCD adherence rates are only 55–74%. Studies have introduced interventions for pediatric SCD adherence, but no review has synthesized these data.

Methods

We conducted a systematic review of interventions for enhancing medication adherence in pediatric SCD. There were 9 studies that met inclusion and exclusion criteria. The Pediatric Self-Management Model provided a framework for organizing the modifiable factors targeted by existing interventions.

Results

The 9 studies had high risk of bias levels and most targeted hydroxyurea. All studies used multiple measures of adherence, the interventions were multicomponent, and most included behavioral or technological interventions. There was variability in terms of whether the intervention targeted the individual, family, community, or healthcare system.

Conclusions

Consistent with the broader adherence literature, targeting knowledge alone was insufficient in increasing adherence. Findings suggest that reminders and targeting self-efficacy were key to success. In addition, addressing multiple domains in an intervention yielded larger effects on adherence. Although these results are promising, this review highlights several limitations of the extant literature, including a paucity of intervention studies and several methodological weaknesses, such as small sample sizes, few randomized controlled trials, and variable measures of adherence. Recommendations for advancing scientific understanding of adherence promoting interventions in pediatric SCD are provided.

Hydroxyurea Initiation Among Children With Sickle Cell Anemia

This study assesses characteristics of children with sickle cell anemia associated with hydroxyurea initiation. Medicaid administrative claims from 6 states (2005-2012) were used to identify children with sickle cell anemia enrolled in Medicaid for ≥2 years. Hydroxyurea use was defined as >30 days' supply of filled prescriptions. Children were classified as initiators (no use in year 1; use in year 2) or nonusers (no use in either year). Logistic regression was used to estimate associations between initiation, health care encounters, and demographics. A total of 4435 children were enrolled for 2 years during the study period; 885 (20.0%) initiators and 3080 (69.4%) nonusers. Children had an annual mean of 2.0 sickle cell disease-related inpatient admissions (SD = 2.2), 8.2 sickle cell disease-related outpatient visits (SD = 7.2), and 3.6 emergency department visits (SD = 3.5). The odds of initiating hydroxyurea increased with increasing health care utilization, age, and calendar year (all P values <.05).

Hydroxyurea: Pattern of Use, Patient Adherence, and Safety Profile in Patients with Sickle Cell Disease in Oman

OBJECTIVES

Many barriers contribute to the underutilization of hydroxyurea (HU) in the treatment of sickle cell disease (SCD), and adherence to its use is often reported to be suboptimal. It is important to have information on the safety of HU in patients with SCD. Our study assessed the pattern of use, patients' adherence to medication, discontinuation of use, and safety of HU in patients with SCD.

METHODS

This cross-sectional study was conducted in the department of medicine of a referral hospital in Oman over five months and included a review of patient files and patient interview. Approval was obtained from the Regional Research and Ethics Committee of the A'Dakhiliyah Governorate and the hospital administration. The parameters were compared between groups using the chi-square test.

RESULTS

Of 298 patients studied, 128 (43.0%) had used HU at some points. The difference in the prevalence of HU use was statistically significant based only on age (p = 0.014), with younger patients more likely to be currently using HU or used HU in the past. The majority of patients were adherent (82.5%) based on self-reported adherence. The prevalence of discontinuation (temporary or permanent) of HU use was high (57.0%), and suspected adverse drug reaction (ADR) was the most common reason. Among those who had never used HU, 33.7% of patients had an indication for the initiation of HU. A quarter of patients who used HU developed a suspected ADR, with blood abnormalities being the commonest. The duration of HU use influenced ADR prevalence (p = 0.015).

CONCLUSIONS

Among the current users of HU, the majority of the patients were adherent based on self-reported medication adherence. The prevalence of discontinuation of HU use and instances of non-initiation of HU among those indicated were high. A larger study, ideally of a prospective nature, in various governorates of Oman, would provide a wider picture at the national level.

Greater number of perceived barriers to hydroxyurea associated with poorer health-related quality of life in youth with sickle cell disease

BACKGROUND

Despite medical benefits, hydroxyurea adherence in adolescents is often poor. As part of a baseline assessment of 28 youth (10-18 years) parent dyads who participated in a 6-month feasibility trial to improve hydroxyurea adherence, we measured the relationship between greater barriers to adherence and health-related quality of life (HRQL) from youth and parent perspectives.

PROCEDURE

Barriers were measured using the Adolescent and Parent Medication Barriers Scales with nine hydroxyurea items added. Barriers reported by ≥25% of the sample were considered common. Generic and disease-specific HRQL were measured by PedsQL and PedsQL Sickle Cell Disease modules. Data were analyzed using descriptive statistics, Cronbach alpha, Spearman correlation coefficients, and paired t tests.

RESULTS

Fifty-six subjects (28 dyads) participated. Youth reported greater barriers compared with parents (5.0 ± 3.9 and 3.5 ± 3.2; P = 0.03), with >80% of respondents reporting ≥1 barriers. Twelve barriers were reported by ≥25% of adolescents, whereas six were reported by ≥25% of parents. Of these, only two were common to both dyad members. Approximately one-third of youth had generic and disease-specific HRQL scores that fell at or below cutoff scores, suggesting being at risk for impaired HRQL. Greater barriers were inversely associated with poorer generic (parent r = -0.43, P = 0.03; youth r = -0.44, P < 0.001) and disease-specific HRQL (parent r = -0.53, P = 0.005; youth r = -0.53, P < 0.001).

CONCLUSIONS

Hydroxyurea barriers were frequently reported but differed by dyad members' perspective. Greater barriers were associated with poorer generic and disease-specific HRQL. To reduce barriers to hydroxyurea in youth with sickle cell disease, perspectives of both dyad members should be addressed.

Hydroxyurea prescription, availability and use for children with sickle cell disease in Italy: Results of a National Multicenter survey

BACKGROUND

The number of patients with sickle cell disease (SCD) has increased in Italy in the past decade due to immigration. In spite of the established efficacy of hydroxyurea (HU) in childhood, population-based data regarding its prescription and effectiveness come mainly from studies performed in adults or outside Europe.

POPULATION AND METHODS

The Hydroxyurea in SCD: A Large Nation-wide Cohort Study from Italy was a retrospective cohort study of adult and pediatric patients with SCD attending 32 centers. Pediatric data are analyzed separately.

RESULTS

Out of 504 children followed in 11 centers, 206 (40%) were on HU (194 SS/Sβ°, 12 SC/Sß+); 74% came from Sub-Saharian Africa and 18% from Europe. HU therapy indications for SS/Sβ° patients were as follows: 57% painful vaso-occlusive crisis, acute chest syndrome or both, 24% anemia, 8% anemia, and other reasons (the majority had Hb ≤ 8-8.5 g/dl, revealing scarce acceptance of low Hb values by pediatric hematologist). Mean starting dose was 15.5 mg/kg, and dose at full regimen was 17.1 mg/kg. Mean age at HU therapy was 7.68 years, although it was lower for SS/Sβ° patients. Only 10% started HU before 3 years. In 92%, 500 mg capsule was used; in 6%, the galenic was used; and in 2%, 100 mg tablet was used. Significant reduction of clinical events and inpatients admissions, with improvement in hematological parameters, was observed for SS/Sβ° patients and a trend toward improvement for SC/Sß+ patients was also observed.

CONCLUSIONS

HU effectiveness is demonstrated in a national cohort of children with SCD living in Italy, even at a lower dose than recommended, revealing good adherence to a treatment program by a socially vulnerable group of patients such as immigrants.

Tablet/Capsule Size Variation Among the Most Commonly Prescribed Medications for Children in the USA: Retrospective Review and Firsthand Pharmacy Audit

INTRODUCTION

Children are frequently asked to take tablets and capsules of different sizes and shapes to manage acute and chronic medical conditions. Medication size is an important factor that contributes to compliance, yet few studies detail size variation or pediatric pharmacy inventory.

OBJECTIVE

This study assesses the available sizes and size variations of common inpatient and outpatient pediatric medications and provides an inventory of the tablet and capsule sizes available in a children's inpatient hospital pharmacy.

METHODS

We derived the most frequently prescribed oral medications from US national databases, including the IMS, Vector One(®): National (VONA) and Pediatric Health Information System (PHIS). We analyzed a composite list using the National Library of Medicine Pillbox website, which provides size measurements. Medications from a children's inpatient pharmacy were audited and hand measured for comparison.

RESULTS

We created a list of the top 15 most prescribed inpatient and outpatient pediatric tablet/capsule medications and observed a wide variation in size: acetaminophen 500 mg ranged from 5 to 22 mm in length, median 15 mm. Common pediatric antibiotics were larger and ranged from 8 to 25 mm in length, median 17 mm. Hand-measured samples from the inpatient pharmacy were often the larger pill sizes, despite smaller alternatives being available.

CONCLUSIONS

We observed a marked variation in the sizes of common pediatric tablet/capsule medications, and pharmacies that serve children may not stock the most child-friendly medications. Tablet/capsule size does not appear to be considered when decisions about tablet and capsule medication selections are made. These results should increase awareness of these sizes and affect how physicians prescribe, how pharmacies order inventory, and how insurers and pharmaceutical companies pay for and produce pediatric medications.

Pharmacokinetics and bioequivalence of a liquid formulation of hydroxyurea in children with sickle cell anemia

Hydroxyurea (HU) is a crucial therapy for children with sickle cell anemia, but its off-label use is a barrier to widespread acceptance. We found HU exposure is not significantly altered by liquid vs capsule formulation, and weight-based dosing schemes provide consistent exposure. HU is recommended for all children starting as young as 9 months of age with sickle cell anemia (SCA; HbSS and HbSβspan(0) thalassemia); however; a paucity of pediatric data exists regarding the pharmacokinetics (PK) or the exposure-response relationship of HU. This trial aimed to characterize the PK of HU in children and to evaluate and compare the bioavailability of a liquid vs capsule formulation. This multicenter; prospective; open-label trial enrolled 39 children with SCA who provided 682 plasma samples for PK analysis following administration of HU. Noncompartmental and population PK models are described. We report that liquid and capsule formulations of HU are bioequivalent; weight-based dosing schemes provide consistent drug exposure; and age-based dosing schemes are unnecessary. These data support the use of liquid HU in children unable to swallow capsules and in those whose weight precludes the use of fixed capsule formulations. Taken with existing safety and efficacy literature; these findings should encourage the use of HU across the spectrum of age and weight in children with SCA; and they should facilitate the expanded use of HU as recommended in the National Heart; Lung; and Blood Institute guidelines for individuals with SCA.