Background Medicines reconciliation in intensive care units (ICU) is essential in preventing medicines errors. Medicines reconciliation errors have been found to occur mainly in the transition of care.

Purpose To develop and evaluate a medicines reconciliation programme in critically ill patients.

Materials and Methods Prospective study. Discrepancies between chronic treatment and treatment prescribed by the hospital physician in patients admitted to the ICU were analysed. Medicines histories were obtained from the medical history and patient interview. If discrepancies were found, the ICU physician was contacted.

Results A total of 50 patients were studied (mean age 62.7 years, SD 13.2). 60% of patients showed at least one reconciliation error. The average number of drugs involved in reconciliation errors was 1.8 (SD 1.2) per patient. A total of 54 (17%) drugs discrepancies were found. The most common error was omission of a regularly used medicine (74%), followed by discrepancies in the frequency (9%), incorrect drug (9%) and incorrect dose (8%). Antihypertensive drugs represented 37% of all discrepancies. Pharmacists made interventions in 98% of discrepancies. Most pharmacist interventions consisted of the addition of an omitted drug (66%) and dosage adjustment (9.4%). 81% of recommended interventions were accepted by ICU physicians. Most rejected interventions were due to the patient’s clinical status (70%).

Conclusions Critically ill patients showed a high incidence of medicines reconciliation errors. Most reconciliation errors consisted of omissions of chronic medicines and involved antihypertensive drugs. 81% of pharmacist interventions were accepted. Medicines reconciliation could reduce medicines errors in critically ill patients and should be incorporated into the daily routine of the pharmacist responsible for the unit.

No conflict of interest.