Looks a lot like another medication sometimes used to treat RLS associated with opioid withdrawal, Ropinirole.
Frankly I tend to believe GBP is more appropriate along with something like clonidine and diazepam when it comes to really severe RLS, but if your symptoms aren't insane this med should help.
I'd this a shot though. If you get any uncomfortable side effects stop taking it and push for GBP. Ropinirole can lead some weird side effects (though I didn't notice any), so I imagine this might as fell for some people.
Let us know how it works/what you end up doing.