The previous slides have reviewed information about  the magnitude of adverse drug reactions and the burden they place on the healthcare system.  How much do drug interactions contribute to the total number of  preventable ADRs?

Again, estimates of the  numbers of patients injured due to drug interactions vary widely.  However, some reasonable estimates come from the work of Dr. Lucien Leape and colleagues.{Leape}  In a systems analysis of ADRs, they estimated that drug-drug interactions represent from 3-5% of all in-hospital medication errors.  Drug interactions are also an important cause of patient visits to physicians and emergency departments.{Raschetti}

Leape LL, Bates DW, Cullen DJ, Cooper J, Demonaco HJ, Gallivan T et al. Systems analysis of adverse drug events. ADE Prevention Study Group. JAMA 1995; 274(1):35-43.
Raschetti R, Morgutti M, Menniti-Ippolito F, Belisari A, Rossignoli A, Longhini P et al. Suspected adverse drug events requiring emergency department visits or hospital admissions. Eur J Clin Pharmacol 1999; 54(12):959-963.