Claim: Naproxen causes stiffness.
Evidence: Naproxen -LRB- brand names : Aleve , Naprosyn , and many others -RRB- is a nonsteroidal anti-inflammatory drug -LRB- NSAID -RRB- of the propionic acid class -LRB- the same class as ibuprofen -RRB- that relieves pain , fever , swelling , and stiffness.