Objective: To identify the accessibility of sources of pre-admission medication (PAM) information, to quantify agreement between the PAM list and the 'gold-standard' PAM list (GS-PAML) and to categorise disagreements.

Methods: A random selection of patients with chronic illness admitted via accident and emergency to one of two study hospitals in the Republic of Ireland were recruited.  For each patient, a GS-PAML was compiled and PAM lists were obtained from each relevant source, including patient own medications, general practitioner (GP) referral letter, past inpatient prescription (Kardex) and discharge summary, nursing home letter and personal communication with GP staff, community pharmacy staff and nursing home staff.  Data were collected regarding availability for use of each source and allergy status.  The GS-PAML was compared to each PAM, and disagreements were identified and categorised.

Key findings: Data were collected for 134 patients.  Community pharmacy and nursing home staff were most accessible to researchers when undertaking the medication history (more than 90%), followed by GP staff (66%).  Except for nursing home sources, agreement between PAML and GS-PAML was low (2-17% of patients, 44-77% of medications).  The community pharmacy PAML most frequently agreed with the GS-PAML (17% of patients, 77% of medications) followed by GP staff (10% of patients, 69% of medications).  Previous (within the last 6 months) discharge summaries (3% of patients, 49% of medications) and GP referral letters (2% of patients, 44% medications) agreed least frequently.  Nursing home (100%) and GP (91%) staff provided most accurate allergy information.  Drug omission (more than 35%) was the most common disagreement for all sources except nursing home staff.  GP staff and community pharmacy PAMLs contained a considerable proportion of commission discrepancies.

Conclusions: Community pharmacy and GP staff were identified as the most available and accurate sources of PAM information and should be prioritised when undertaking admission medication reconciliation in a busy clinical environment.