Poor-tasting pediatric medicines: Part 1. A scoping review of their impact on patient acceptability, medication adherence, and treatment outcomes

FIGURE 1 The relationship between medication palatability and patient acceptability, which in turn can impact medication adherence and the safety and efficacy of the treatment.

Abstract

Background: Many medicines for children taste bitter and unpleasant, presenting a significant barrier to effective pharmacotherapy. Anecdotally, this issue is widely recognized; however, empirical evidence on the consequences of unpalatable medicines remains scarce and fragmented. The objective of this scoping review was to investigate the impact of poor tasting pediatric medicines on patient acceptability, medication adherence, and/or treatment outcomes.

Methods: A literature search was performed in MEDLINE/PubMed, EMBASE and CINAHL from inception to June 2023. Eligibility criteria included interventional or observational studies conducted in children aged 0–18 years (population), administered an unpalatable oral medicine (exposure), with any reported impact on patient acceptability, medication adherence, and treatment effects (outcomes). Study screening and data extraction was completed using a standardized form on Covidence.

Results: After searching 2,282 citations and reviewing 429 full-text papers, 225 articles were included in the final analysis. The impact of poor-tasting medicines was observed across 77 diseases or indications, with 156 different unpalatable medicinal products identified. Outcomes were most frequently linked to reduced patient acceptability, with 64% of articles reporting rejection responses, the need for strategies to aid administration (from positive reinforcement to physical restraint and forced administration), and impacts on prescribing practices (e.g., use of non-first line alternative therapies). Medication adherence impacts were reported in 27% of the reviewed studies, where poor taste was reported as a barrier to adherence in chronic diseases and correlated with incomplete dose administration in acute conditions. A small number of studies linked palatability with treatment outcomes, including viral suppression in HIV and seizure control in epilepsy.

Conclusion: This review highlights the widespread adverse impact of poor-tasting pediatric medicines on patient experiences and outcomes, though the true extent of the issue may still be underreported. The problem affects children worldwide, across all age groups, and is frequently noted by parents, caregivers, and healthcare professionals in both clinical and domiciliary settings. These findings emphasize the need for the development and prescription of more palatable medicines for children, as well as the advancement of more universal taste-masking strategies to address this widespread problem.

Introduction

Globally, approximately 30% of the population, or around 2.4 billion people, are babies, children, and adolescents under the age of 18 years (United Nations, 2022). Almost all of this pediatric population will need to take medicines at some point during this stage of life, be it over-the-counter (OTC) products for minor, acute ailments to regular prescribed medicines to manage chronic diseases. Two important concepts must be considered when developing and prescribing medicines: patient acceptability, namely, the overall ability and willingness of the patient to use and its care giver to administer the medicine as intended (European Medicines Agency, 2013); and medication adherence, the degree to which use of medication by the patient corresponds with the prescribed regimen (World Health Organization, 2003). Even the most efficacious drug treatments will be futile if patients do not take them as required.

Palatability is a crucial factor that impacts patients’ experiences of taking medicines. Regulatory agencies define this as the overall appreciation of an (often oral) medicinal product in relation to its smell, taste, aftertaste and texture (i.e., feeling in the mouth) (European Medicines Agency, 2013) and the quality of a drug product that makes it pleasant or acceptable in terms of these attributes (Food and Drug Administration, 2018). However, developing palatable medicines is challenging due to a major obstacle: many drugs have bitter and unpleasant tastes (Mennella et al., 2013). This is unsurprising, as most drugs are xenobiotics – chemical substances not naturally produced or expected to be present within the body – that can exert biological, and potentially adverse effects (Schiffman et al., 2002). Thus, bitterness is an innately aversive sensation that serves as an evolutionary, biological warning to prevent the ingestion of potentially toxic and harmful substances (Breslin, 2013; Wooding et al., 2021). Despite this natural aversion, it is crucial that patients are able to take their medications for effective clinical treatment.

Indeed, patients of all ages are more likely to prefer better-tasting medicines with favorable sensory and organoleptic properties, but this issue is particularly challenging in children. While adults are often able to tolerate unpalatable medicines due to their understanding of the health benefits, children’s experiences are shaped by their cognitive development and more primal sense of what is acceptable or not. Young patients may lack the ability to fully understand the importance of taking medication or cooperate in its administration. Taste perception is a complex process, and sensitivity and responses to the same stimuli can vary considerably among individuals. This can be influenced by a multitude of confounding factors including age, sex, genetics, ethnicity, and health status (Shizukuda et al., 2018; Cattaneo et al., 2022). Taste perception first develops in-utero and matures with age, though children have a recognized preference for sweet tastes and dislike for bitter stimuli which stems from their innate biology (Mennella and Bobowski, 2015; Ustun et al., 2022; Mennella, 2014). Studies have shown that children are more sensitive to bitter tastes compared with adults when exposed to the same stimulus (Ranmal et al., 2023; Mennella et al., 2005; Mennella et al., 2010).

In its seminal guideline on the pharmaceutical development of pediatric medicines, the European Medicines Agency (EMA) acknowledges that palatability is one of the main elements of the patient acceptability, and in turn, patient acceptability is likely to have a significant impact on patient adherence and consequently, on the safety and efficacy of a medicinal product (European Medicines Agency, 2013). The United States Food and Drug Administration (FDA) also notes this association between palatability and patient acceptability, and the resulting impact on adherence, a key factor in successful therapeutic intervention (Food and Drug Administration, 2018). This proposed relationship is illustrated in Figure 1, showing in turn how medication taste can facilitate or compromise these related outcomes. This relationship is logically sound and anecdotally, the issue is widely recognized; however, empirical evidence demonstrating the impact of bad-tasting medicines is scarce and fragmented.

The objective of this scoping review was to investigate the impact of poor tasting pediatric medicines on three key concerns: patient acceptability, medication adherence, and treatment outcomes. A scoping review allowed this broad research question to be explored by systematically searching and synthesizing existing knowledge, while mapping key concepts and identifying gaps in evidence (Colquhoun et al., 2014). Insights into the real-world experiences of pediatric patients and their caregivers also provides valuable understanding of the practical challenges faced in administering unpalatable medicines. This is complemented by an accompanying article on the experiences of pediatric healthcare providers and caregivers in the United States and Sub-Saharan Africa (El-Sahn et al., 2025).

The conduct and reporting of the review was guided by the JBI Manual for Evidence Synthesis (Peters et al., 2020) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) (Tricco et al., 2018). In line with the Population-Concept-Context (PCC) framework recommended by JBI, the review focused on: 1) population: children aged 0–18 years; including studies with patients, caregivers, and healthcare professionals (HCPs) involved in medicines administration; 2) concept: exposure to a bad tasting or unpalatable oral medicinal product impacting patient acceptability and administration, medication adherence, and/or therapeutic outcomes; and 3) context: any disease area or ailment and across all geographical locations.

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Sejal R. Ranmal, Jennifer Walsh and Catherine Tuleu, Poor-tasting pediatric medicines: Part 1. A scoping review of their impact on patient acceptability, medication adherence, and treatment outcomes, SYSTEMATIC REVIEW article, Front. Drug Deliv., 22 April 2025, Sec. Drug Delivery for Special Patient Populations, Volume 5 – 2025 | https://doi.org/10.3389/fddev.2025.1553286