Delivering healthcare can be complex and error prone. Five to seven per cent of prescriptions involve errors, with medicines after hospital discharge being particularly associated with adverse health consequences. The dispensing error rate in pharmacies has been estimated at between 0.01 and 3.32 per cent of dispensed medicines. It is clear from reports from the National Reporting and Learning System (NRLS) that things go wrong at every stage, from prescribing through to dispensing, supply, administration and monitoring. The medications of most concern are those with the greatest potential for harm both due to their inherent toxicity and the number of patients exposed to them.

Of particular note are insulin, opiates, methotrexate, warfarin and lithium. Pharmacists and pharmacy technicians make patient safety interventions multiple times a day, to great effect. Every clinical intervention could be considered a patient safety incident averted. Reporting more pharmacy interventions to the NRLS would greatly increase our understanding of what goes wrong at the prescribing stage in primary care. In addition, pharmacy teams prevent errors that may be made by the patient. Supporting adherence, building understanding and optimising therapy, especially where there are multiple morbidities and polypharmacy, all contribute to the safety of medication use.