Does phentermine induce or provoke relapse of substance abuse? Statement of the Issue: FDA drug labeling and the PDR state that phentermine is contraindicated in patients with a history of drug abuse. The FDAs hypothesis is that phentermine, a category IV controlled substance, prescribed for such patients can provoke relapse of drug abuse (first hypothesis). A corollary hypothesis, which must also be true for the first hypothesis and the FDAs contraindication to be valid, is that phentermine has significant human addiction potential (second hypothesis). Origin of the Issue & Historical perspective: Phentermine was approved for marketing by the FDA in 1959. At the time phentermine was approved, far less was understood of the nature of stimulant drug abuse than is the case today. At that time, the favored hypothesis was that stimulant abuse potential was directly correlated to stimulant potency. No suggestion of abuse or depe
