"Every product the FDA evaluates looks at its benefit-to-risk ratio," she tells WebMD. "If you look at it from the standpoint of a cancer patient, one might be more willing to accept the adverse events of a certain drug more readily than when using a product that you don't necessarily need to improve health. Therefore, we really look at their safety."
Prior to its approval as a wrinkle treatment, the FDA initially approved Botox in 1989 to treat two eye disorders -- uncontrollable eyelid spasms and misaligned eyes -- and in 2000 to treat a condition that causes severe neck and shoulder contractions. It was a Canadian eye surgeon who first noted its wrinkle-reducing properties.
In other countries, such as the U.K., Botox has already been approved for other conditions, including excessive sweating and spasticity.
"Interestingly, except for cosmetic use, the U.S. is usually far behind other countries in the drug approval process," says Allergan spokeswoman Christine Cassiano, who acknowledges that Botox is currently being studied by private researchers and in corporate-funded clinical trials to test some of its other potential uses.