Definition: (Of a drug or treatment). The maximum ability of a drug or treatment to produce a result regardless of dosage. A drug passes efficacy trials if it is effective at the dose tested and against the illness for which it is prescribed. In the procedure mandated by the FDA, Phase II clinical trials gauge efficacy, and Phase III trials confirm it
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Source:
ClinicalTrials.gov
Examples: Trials have shown the efficacy of Depakote, Topamax, propranolol, and timolol for Migraine prevention.
