The best-known treatment for Parkinson's disease isn't perfect. That is why, after nearly five decades, a drug known as ketamine is being repurposed to potentially help Parkinson's patients in a new clinical trial at the UA College of Medicine - Tucson.
The drug named Levodopa can treat the stiffness and slowness of movement associated with the disease. "The problem is Levodopa works great for a few years, but then you start getting these side effects," says Scott Sherman, MD, PhD, a neurologist at the University of Arizona College of Medicine - Tucson.
According to Sherman, forty percent of patients on Levodopa eventually experience dyskinesia, uncontrollable and involuntary movements of the arms, legs, head or entire body.
"Patients that have uncontrolled movements of their limbs and face, these can be mild but sometimes they become so extreme that the patients need to lay down to wait until the side effect passes which could be hours," he said.
Unless patients stop Levodopa treatment altogether, these movements do not go away. Now, UA researchers will repurpose ketamine, a drug currently used to treat pain and depression, to try to reduce these involuntary movements brought on by Levodopa.
"Patients would be able to continue taking their medications and they would get a treatment of ketamine about once a month get an infusion that would last about 6 hours," he explained.
Led by Dr. Sherman and Torsten Falk, Ph.D., a neuroscientist in the UA Department of Neurology, the two will launch a small phase I clinical trial this summer at the UA College of Medicine - Tucson. The trial is supported by a three-year $750,000 grant from the Arizona Biomedical Research Commission (ABRC). They will use 10 patients in their first clinical trial which will verify that Dr. Sherman's hunch holds true - that ketamine is tolerable and effective for treating dyskinesia.
Sherman says the treatment would last for many weeks and calm the abnormal movement. The combination of the two could be a good option for treating some patients that would otherwise need surgical procedures, he said.
Repurposing ketamine, a drug that has 50 years of safety, for other indications lets the process go quicker, Falk said. He expects the treatment to be available soon.