My neurologist just told me last week that restless leg is part of peripheral neuropathy. I only get maybe once or twice a year. My mom had it almost nightly.
I do get REMICADE infusions and before they run the REMICADE they run an intravenous dose of Benadryl. A few times I have gotten restless legs during the Benadryl and nurses have told me it is the benadryl.
Hope you find an answer to your problem, try to see a neurologist.