These dosage changes reveal a discrepancy between the dosage information gathered from pre-marketing studies and that needed for safe and effective use in clinical practice. Avoiding needless overdosing could reduce both side effects and costs of prescription drugs.
In the modern drug development process, great pressure is placed on defining a drug dosage early in the clinical evaluation stage, when information about the drug and its actions is sparse. Ideally, this dosage should remain the same throughout the lifetime of the drug, but the studies published this week indicate that the dosages of cardiovascular and most other classes of drugs are initially overestimated. These overestimated doses are discovered at various times after the drug is introduced into medical practice.
The Georgetown researchers studied the label changes made for all the new drugs approved for use in the United States by the FDA between 1980 and 1999. The team was led by James Cross, MS, regulatory project manager in the FDA's Center for Drug Evaluation and Research (CDER), who was a CDDS research fellow when the research was conducted. They found that dosage changes occurred in 21% of the drugs. Of these, 79% were due to safety concerns. "This pattern may represent a systematic flaw in pre-marketing dosage evaluation," the authors said.
In a separate paper, Dutch researchers from Utrecht University and Maastricht University, observed a similar proportion of dosage changes in drugs introduced in other countries, with t
Contact: Beth Porter
Georgetown University Medical Center