A public interest group petitioned the Food and Drug Administration on Thursday to increase the warnings on the popular cosmetic and drug Botox.
Dr. Sidney Wolfe of Public Citizen Health Research Group said severe reactions including deaths have been linked to the product.
Botox and another drug, Myobloc, use botulinum toxin, which blocks nerve impulses to muscles, causing them to relax.
But in a few cases, the toxin has spread to other parts of the body, resulting in problems including paralysis of respiratory muscles and difficulty swallowing, potentially leading to food or liquids entering the lungs and causing aspiration pneumonia, Wolfe said.
Public Citizen sought so-called black box warnings on both products.
Botulinum toxin is approved for such uses as easing muscle spasms and crossed eyes. Botox is also approved for one cosmetic use — treatment of wrinkles between the eyebrows.
Botox maker Allergan did not immediately respond to requests for comment on the petition.
According to the petition, there have been 180 reports of adverse effects in the United States including 16 deaths.
While the possibility of dangerous side effects is noted in the detailed information available for the products, that is not always available to the public. The enhanced warnings would make people aware of the possibility of side effects so they could seek help if they experienced early symptoms such as dry mouth, difficulty swallowing, difficulty breathing, slurred speech, drooping eyelids and muscle weakness.