Phenylpropanolamine is similar to amphetamine, but does not cause euphoria and does not have the same potential for abuse. Phenylpropanolamine was used as a cough and cold agent initially, since it relieves congestion associated with the common cold. Before long, people realized that it caused
appetite suppression and that they were able to lose weight while taking it. In the 1940s, phenylpropanolamine became popular as a diet aid and stimulant. In 1951, the FDA enacted laws requiring people to have a doctor’s prescription to obtain certain drugs; phenylpropanolamine, however, was not covered by these regulations.
Phenylropanolamine was initially believed to have a very low risk of side effects, and the FDA allowed it to be available over the counter, without a prescription. After some time, phenylpropanolamine became the active ingredient in many nonprescription diet pills, such as Acutrim®, Dexatrim®, and
Protrim. Early studies demonstrated that the drug’s main side effect was an increase in energy that sometimes led to insomnia or agitation.
Phenylpropanolamine works by increasing dopamine and norepinephrine in the feeding center of the brain, which causes appetite suppression. Beginning in the 1970s, the FDA began to gather reports of individuals experiencing hemorrhagic stroke, a life-threatening bleeding in the brain or the tissue surrounding the brain, that was related to phenylpropanolamine’s stimulant effects. These strokes
generally occurred in young women and were suspected of being a result of very high blood pressure caused by phenylpropanolamine use.
In 2000, a report from Yale University determined that use of phenylprolamine-containing appetite suppressants made individuals 16 times more likely to have a hemorrhagic stroke. Phenylpropanolamine had also been linked to heart attacks and high blood pressure in many patients. Therefore, in November 2000, the FDA asked pharmaceutical manufacturers to stop marketing products containing phenylpropanolamine.
Many of the products originally containing phenylpropanolamine are still legally available, but have been reformulated with a different active ingredient and no longer contain phenylpropanolamine.