IDK why someone is saying loperamide. It is an opioid, so its not an option. Plus, anything near a dose to help alleviate RLS on a regular basis will leave you with dangerously unhealthy constipation.
The best answer so far has been to try Ondansetron AKA Zofran and next a non selective beta blocker like Propranolol. And I hate to be pessimistic but they are not going to come close to relieving your RLS as well as opiates. Still worth giving it a try as they are both classes of medication you have not tried before and they are relatively harmless.
Also, IMO this is just like using benzos for anxiety. Of course they work better than anything else for the ailment but the rebound symptoms can seem 5x as bad.