In 2002, the U.S. Food and Drug Administration (F.D.A.) approved the use of injected botulinum toxin type A (Botox) for temporary reduction in the appearance of wrinkles between the eyebrows. It soon became apparent that the treatment was also effective at other sites and in 2013, the FDA approved its use for lines at the sides of the eyes (crow's feet). In its 2014 compilation of usage and trends, the American Society of Plastic Surgeons reported that 6.6 million injections of Botox were performed that year.
"The cosmetic use of Botox for wrinkle reduction is so well known that its therapeutic use for a variety of medical problems has been overshadowed," says Alicia Cool, M.D., board-certified dermatologist at Advanced Dermatology P.C. (New York City). "Botox injections work by temporarily weakening or paralyzing targeted muscle and make Botox an effective treatment for some conditions that are caused by spasmodic muscle contractions."
The botulinum toxin type A that is used for both cosmetic and medical purposes is a small dose of the same toxin that causes the dangerous food poisoning known as botulism. It is a protein complex produced by spores of the bacteria Clostridium botulinum. Small doses of purified botulinum toxin prevent nerve cells from releasing a chemical that triggers muscle contraction and were initially used - and approved by the F.D.A. in 1989 - to treat two disorders of the eye muscles: uncontrolled blinking (blepharospasm) and misaligned eyes (strabismus). Doctors noticed that a side effect of relaxing the underlying eye muscles was that the vertical lines between the eyebrows were softened and smoothed. Following studies that verified that frown lines were reduced for up to 120 days, the F.D.A. approved the use of Botox for that purpose and later for treating crow's feet.
While the use of Botox for its cosmetic effects continues to gain popularity, the F.D.A. has also approved its use for several medical conditions in addition to eye muscle disorders, including:
- Chronic migraine: People with chronic migraine suffer with debilitating headaches as much as half the time and many have been unable to find relief. The F.D.A. has approved Botox for patients who suffer more than 14 headaches a month; injections around the temples, forehead, neck and shoulders may reduce the number of occurrences.
- Excessive sweating: Botox is approved for treatment of axillary hyperhidrosis (over-activity of the underarm sweat glands). It works by blocking the release of the chemical that stimulates sweat glands.
- Overactive bladder: Botox injected into the wall of the bladder relieves symptoms such as frequent urination, nighttime waking to use the bathroom, and urinary incontinence.
- Cervical dystonia: Botox reduces the severe contractions of the neck and shoulders that characterize this neurological disorder.
- Upper limb muscle spasms: Botox can be used to decrease spasticity in the flexor muscles of the elbow, wrist, and fingers in adults with conditions such as stroke, traumatic brain injury, cerebral palsy, or progressive multiple sclerosis.
There are additional uses of Botox that have not been approved by the FDA, known as "off label" usage. One example is a smile in which too much of the upper gum is visible. Injecting Botox into the upper lip relaxes the retractor muscles so the lip won't raise as high when smiling and less gum will show.
"The effects of Botox injections are temporary," says Cool. "And they vary in duration depending on the condition being treated. But in all cases - whether for medical or cosmetic therapy - Botox should be administered only by a highly qualified medical professional and only in the lowest effective dose. Botox isn't a wonder drug or a fountain of youth. But - used properly - it is a minimally invasive solution for a wide variety of conditions."