A recent study found “that 6.5% of all adult nonobstetrical patients admitted to two teaching hospitals suffered an adverse drug event”; and that “most errors occurred in the physician ordering (39%)”. Even more interesting are what caused the errors by the physicians:

• Lack of knowledge about the drug 36%
• Lack of information on the patient 24%
• Rules violation 19%
• Slips and memory lapses 11%
• Inadequate monitoring 8%
• Other 2%

SOURCE: Leape LL, et al. Systems analysis of adverse drug events. JAMA1995;274: 35-43