The kidney plays a critical role in the elimination of many drugs from the body, hence consideration should be given to a patient’s renal function whenever any drug is prescribed. Much kidney disease is unrecognized, but the widespread reporting of estimated glomerular filtration rates (eGFR) has brought greater awareness of the prevalence of chronic kidney disease (CKD) and thereby encouraged medical practitioners to take account of reduced renal function when prescribing. CKD is very often one of many coexisting comorbid conditions, especially in elderly patients, when particularly careful thought must be given to appropriate drug dosing and the possibility of drug interactions....