Primary care electronic medication record discrepancies in patients starting treatment at a hospital-based ambulatory care pharmacy and impact on prevalence of potential drug-drug interactions.

About 40% of patients had one or more medications in the EMR which they were not taking and one fifth used medications that were not listed in the EMR. EMR should not be used as the only source of information when screening for DDIs, especially in patients followed by different medical specialties or combining private and public healthcare.