A few examples include an anticonvulsant, analgesic, and anxiolytic medication used to treat epilepsy, neuropathic pain, fibromyalgia, restless leg syndrome, opioid withdrawal, and generalized anxiety disorder that has been repurposed as an IOP-reducing agent (pregabalin [228]), a prostaglandin EP2-receptor agonist [227], an autotaxin/lysophosphatidic acid receptor antagonist [229] and a TRPV-4 antagonist [50,51] (see [127] for more information on these and additional investigative drug candidates). This evidence concerns the gene TRPV4 and restless legs syndrome.