What is the best otc pain medicine for a sprained knee?

NSAIDs : Try motrin, ibuprofen, Naproxen with food and as long as you don't have gastritis or stomach problems.Ice, elevation and rest helps as well. Tylenol (acetaminophen) if stomach problems, kidney or heart problems.

Magnesium salicylate: Support the sprained area with local muscle rub and ace wrap herb horsetail extract also helps to repair tendons.

Ibuprofen or similar: Nonsteroidal anti-inflammatories, such as Ibuprofen are best for sprains. Icing the knee intermittently can also help, while elevation may help keep swelling down.

Knee sprain: Nonsteroidal anti-inflammatory drugs (NSAIDS) can help with both pain relief and in reducing inflammation. Examples are ibuprofen (like Advil, Nuprin or Motrin), Naproxen sodium (like Aleve, (naproxen) Naprosyn, Anaprox) or Asprin (such as Bayer, Ecotrin, Ascriptin). Avoid NSAID's if pregnant or allergic to them. In that situation can consider acetaminophen.