1School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia, 2School of Pharmacy, An-Najah National University, Nablus, Palestine, and 3Department of Medicine, Penang Hospital, Penang, Malaysia

Background and objective: Adverse drug events (ADEs) are a common cause of hospitalization and in-hospital complications. The aim of this study was to determine the rates, types, severity and preventability of pre-admission and in-hospital ADEs in patients with chronic kidney disease (CKD). Methods: This study was conducted at the nephrology unit at Penang General Hospital. A random sample of 300 adult patients with CKD was included. Medical records and charts were reviewed by a clinical pharmacist every work day to find any evidence of errors or complications related to drug use. If a suspected ADE was found, further investigations were carried out to assess the causality, severity and preventability of the event. Results: A total of 159 ADEs were reported in 122 (40.7%) of the patients. We found 86 suspected pre-admission ADEs in 68 (22.7%) of the patients. These were either the cause of admission for some patients or discovered by the initial physical examination and laboratory investigations. During hospitalization, 64 (21.3%) patients had 73 suspected ADEs. Out of the total 159 suspected ADEs, it was highly probable that 31 events were due to medication, while 61 were of lower probability, and 67 were merely possible. A total of 48 (30.2%) events was considered preventable. 46 events (28.9%) were serious, 93 (58.5%) were less serious and 20 (12.6%) were insignificant. The medication classes most frequently involved in ADEs were diuretics, antibacterials, drugs used for diabetes mellitus, antithrombotic agents, mineral supplements and antihypertensive drugs. Conclusion: ADEs are very common in hospitalized CKD patients, and some of these events are preventable. The service of a clinical pharmacist may help to reduce ADEs.