Taking a muscle relaxant is compatible with your other medications, but you must be careful to check the ingredients. Many over-the-counter formulas contain ibuprofen (Robaxplatine or generic brand, Motrin muscle pain), which is an anti-inflammatory like Naproxen and should be avoided. There is a combination of muscle relaxant and acetaminophen (e.g. Robaxacet) available over-the-counter that would be compatible with your other medications. However, it should be noted that muscle relaxants can cause drowsiness, and when combined with hydromorphone, you should be careful when performing activities that require vigilance and avoid alcohol. If you need any further information, please do not hesitate to contact me.