Kidney impairment is common in the paediatric population. This includes patients with an acute deterioration in kidney function during an episode of acute kidney injury (AKI), patients with chronic kidney disease (CKD) and patients undergoing renal replacement therapy (RRT) or with kidney transplants. Patients with kidney impairment are at increased risk of adverse events associated with errors in drug prescribing and administration.1 This article aims to highlight several key principles prescribers should be aware of when managing these patients, with a particular focus on management in secondary care.

A person’s response to a drug is determined by a combination of pharmacokinetics and pharmacodynamics.2 Pharmacodynamics is concerned with the effect of the drug on the body. Pharmacokinetics is best described as the effect of the body on the drug and reflects the physiological processes of absorption, distribution, metabolism and elimination;2–4 it is important to remember that each of these processes may be altered in kidney disease. Unfortunately, there are no agreed national guidelines on how to adjust doses in kidney impairment. Pharmacists have specialist knowledge which should be used within the multidisciplinary team (MDT) to advise the necessary dosage adjustments.

Absorption may be reduced in patients with kidney impairment for numerous reasons including nausea and vomiting associated with uraemia and oedema of the gastrointestinal tract due to hypoproteinaemia.2 4 Drug doses are not routinely altered to allow for these factors but must be considered when assessing the efficacy of treatment. An example could be switching from oral prednisolone to intravenous methylprednisolone if there was a concern regarding the absorption of the oral medication.

Distribution of drugs is affected as a result of changes affecting protein binding, primarily hypoalbuminaemia. This is particularly important for highly protein-bound drugs, for example, tacrolimus. A higher proportion of unbound drug, due to …