Intended for healthcare professionals


Not too little, not too much: problems of selecting oral antibiotic dose for children

BMJ 2015; 351 doi: (Published 03 November 2015) Cite this as: BMJ 2015;351:h5447
  1. J A Bielicki, clinical research fellow12,
  2. C I S Barker, clinical research fellow 13,
  3. S Saxena, clinical reader in primary care 4,
  4. I C K Wong, professor of pharmacy practice 56,
  5. P F Long, reader in pharmacognosy7,
  6. M Sharland, professor of paediatric infectious diseases 1
  1. 1Paediatric Infectious Diseases Research Group, Institute for Infection and Immunity, St George’s, University of London, London, UK
  2. 2Paediatric Pharmacology, University of Basel Children’s Hospital, Basel, Switzerland
  3. 3Institute of Child Health, University College London, London, UK
  4. 4School of Public Health, Imperial College London, London, UK
  5. 5Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, University of Hong Kong, China
  6. 6Centre for Paediatric Pharmacy Research, UCL School of Pharmacy, University College London, London, UK
  7. 7Institute of Pharmaceutical Science, King’s College London, London, UK
  1. Correspondence to: J Bielicki jbielick{at}
  • Accepted 5 October 2015

J A Bielicki and colleagues compare common strategies for selecting antibiotic dose for children and discuss how best to balance usability with accuracy

Globally, antibiotics are the most common drugs used to treat acutely ill children.1 2 Antibiotic doses should be selected to achieve optimal killing of bacteria with minimal undesirable effects, such as drug toxicity or the selection of resistant pathogens. Given the challenges associated with increasing antibiotic resistance, optimal use of antibiotics for children is important for global antimicrobial stewardship.3

Challenges of achieving optimal dosing in children

Drug dosing in children is more complex than in adults. As the organs and immune system develop throughout childhood, the way in which drugs are absorbed, transported, and eliminated by the body (pharmacokinetics) changes, which in turn affects the drug’s action on the body (pharmacodynamics).4 During the first two years of life, the evolution of renal function and hepatic metabolism have an important effect on the optimal antibiotic dose. Inaccurate dosing can lead to problems because higher antibiotic doses potentiate undesirable side effects, especially diarrhoea, and may promote the selection of resistant bacteria.5

Finding suitable formulations for children is also more challenging than for adults. Antibiotic doses need to be titrated to achieve optimal effectiveness and be adapted to maturational changes.6 Achieving the correct dose may require splitting or crushing tablets, for example.7 Although liquid antibiotic preparations are the most flexible to dose, measuring small volumes can be inaccurate.8 Generally, syringes have been found to be more accurate than dosing cups or spoons,9 and the use of pictures to demonstrate correct dosing can further improve accuracy.10 Nevertheless, in one US study more than two thirds of preventable adverse drug events outside hospital were due to parental errors in administering drugs, indicating the difficulties of providing easy to follow instructions. …

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