Dalfampridine
"Hello. It's been 6 months since I've started taking Ampyra. It is still a miracle drug, and I would recommend it to anyone with MS. The only side effect I've had was slight back pain. That side effect only lasted about 2 weeks. I've noticed a difference  in my walking immediately, and still stand by this med. I do notice if I forget to take a pill, then I have to wait to get back on schedule. that's the only complaint."