Medication adherence and formulation challenges

Overview & Definition

A registrar in a paediatric nephrology clinic sees a 6-year-old renal transplant recipient whose tacrolimus levels have been bouncing unpredictably for months. The dose is correct, the family understands the diagnosis, but the child spits out the bitter liquid and the half-tablets crumble. The registrar reaches for "non-adherence" as the label. This leaf owns that moment — medication adherence and formulation challenges — and reframes it from a failing of the child into a property of the prescribing that the prescriber can fix. The broader pharmacology, off-label use and pharmacovigilance theory lives on its own leaves; this page is about the swallow, the taste and the daily reality of taking medicine as a child. [1] [6]

Hold three words apart, because examiners live in the gaps between them. Adherence is the extent to which a person's medicine-taking behaviour corresponds to the agreed recommendations; it is shared, negotiated and behavioural. Compliance is the older term that implied the patient obeys the prescriber — it is now discouraged precisely because it frames the child or family as the problem. Persistence is the length of time a patient continues to take the medicine before stopping; it is a separate dimension from day-to-day implementation. The ABC taxonomy used in adult and paediatric research separates adherence into initiation (taking the first dose), implementation (taking it as prescribed over time) and discontinuation (stopping); non-adherence can sit in any one of these. [2]

The reason this framing matters clinically is that the formulation is half of adherence. A child cannot be adherent to a tablet they cannot swallow, a liquid that makes them vomit, or a regimen so complex that no family can sustain it. Nunn and Richey's 2005 British Journal of Clinical Pharmacology paper set out the paediatric formulation gap and remains the canonical reference; it is the paper to name at viva. The rest of this page is about closing that gap at the bedside. [1] [3]

References12Show ledgerHide ledger

1. [1]Nunn T Formulation of medicines for children. Br J Clin Pharmacol, 2005.PMID 15948931
2. [2]Dean AJ A systematic review of interventions to enhance medication adherence in children and adolescents with chronic illness. Arch Dis Child, 2010.PMID 20522463
3. [3]Mennella JA Optimizing oral medications for children. Clin Ther, 2008.PMID 19108800
4. [4]Mennella JA The bad taste of medicines: overview of basic research on bitter taste. Clin Ther, 2013.PMID 23886820
5. [5]Salunke S The STEP (Safety and Toxicity of Excipients for Paediatrics) database: part 2 - the pilot version. Int J Pharm, 2013.PMID 24070789
6. [6]Allegaert K Neonates need tailored drug formulations. World J Clin Pediatr, 2013.PMID 25254168
7. [7]Palmeirim MS Efficacy, safety and acceptability of a new chewable formulation versus the solid tablet of mebendazole against hookworm infections in children: a randomised controlled trial. EClinicalMedicine, 2020.PMID 33150325
8. [8]Haslund-Krog SS Acceptability of Prednisolone in an Open-Label Randomised Cross-Over Study-Focus on Formulation in Children. Children (Basel), 2022.PMID 36010126
9. [9]Münch J, Sessler I, Bosse HM, et al. Evaluating the Acceptability, Swallowability, and Palatability of Film-Coated Mini-Tablet Formulation in Young Children. Pharmaceutics, 2023.PMID 37376177
10. [10]Perez F Acceptability of Mebendazole Chewable Tablet in Children Aged 2 to 4 Years in Peru. Pharmaceutics, 2021.PMID 35056923
11. [11]Saito J Drug Formulation for Pediatric Oral Antimicrobial Agents in Japan: Current Status, Prospects, and Challenges. Pediatr Infect Dis J, 2023.PMID 37343212
12. [12]Edgcomb JB Medication Adherence Among Children and Adolescents with Severe Mental Illness: A Systematic Review and Meta-Analysis. J Child Adolesc Psychopharmacol, 2018.PMID 30040434