Friday, February 05, 2016 Botox Approved for Lower Limb Spasticity Six years after gaining FDA approval for the treatment of upper limb spasticity, onabotulinumtoxinA—commonly known as Botox—has now been OK'ed for the same use in lower limbs. According to Medscape (free sign-in required) the FDA approval was based on a clinical trial of more than 400 individuals who were experiencing lower limb spasticity poststroke. Participants treated with Botox showed statistically significant improvements at weeks 4 and 6 in muscle tone and clinical patient benefit. The trials were focused on the ankle and toes, and didn’t confirm use in other areas of the lower extremities. In 2010, FDA approved the use of Botox for upper limb spasticity, but effectiveness was only confirmed for the elbow, wrist, and fingers. Five years later, effectiveness was confirmed for use in 2 thumb muscles.