ABSTRACT
A recent review of postapproval dosage changes between 1980 and 1999 indicates that, of the evaluable drug products ( n = 354), 21% had dosage changes ( 2 , 3 ). Many of these changes were based on new information that was obtained after the marketing approval of the drug products. These changes included dosing recommendations for specifi c populations, such as patients at various stages of renal or hepatic impairment, patients taking specifi c concomitant medications, or patients who are pregnant. This study pointed out the importance of having accurate dosage recommendation for individuals with various intrinsic or extrinsic factors prior to marketing to reduce the risks of adverse drug reactions (ADR). ADRs, accounting for 5% of hospital admissions and also experienced by 10% of hospitalized patients, have led to 700,000 injuries or deaths per year, and were estimated to be the fourth or the sixth leading cause of death in the United States for hospitalized patients ( 4 ). Serious ADRs, caused by various factors, have contributed to market withdrawals. Table 1 lists the drugs withdrawn from the US market in the past 7 years due to safety reasons ( 5 , 6 ).
