There are some benefits and potential dangers.
To hear her now, you'd never know Marquita Lister almost lost it all.
"I've had the kind of life that people only dream about," Marquita Lister, an opera singer, said.
The international opera star was diagnosed with Polymyositis, it attacks the lungs and muscles.
"I almost died," Marquita said.
A medical team at national rehabilitation hospital came up with an innovative form of therapy, including a drug normally used to treat lymphoma patients.
Doctors took a chance with the off-label drug use and it paid off. Marquita pulled through.
Experts say as many as one in five prescriptions in the U.S. is used for something it's not approved for by the FDA, and it's perfectly legal.
Antipsychotic drugs are often prescribed for dementia, anxiety drugs are used as sleep aids and some cancer drugs for eye problems.
Off-label drugs worked for Marquita, but they aren't safe in all cases.
Studies show some anti-psychotics used to treat elderly patients with dementia did show benefits, but also increased risk of death.
Other studies found a drug used to help patients from bleeding uncontrollably during surgery, increased the odds of blood clots when used off-label.
While studies and results may differ on the practice, off-label drugs got Marquita back on stage, for her the risk was worth it.
Off-label drug use is possible because once the FDA approves drugs, physicians are allowed to use their own judgment on what they prescribe it for.
However, the FDA does bar drug makers from promoting their products for off-label use.
Because of that, manufacturers are fighting the off-label rule in court right now, claiming the ban violates their first amendment rights.
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