Most definitely. The last time I was prescribed this drug the leaflette that came with it warned me that weight gain was a likely side effect. I'm pretty sure that weight gain is a possible side effect of all NSAIDs (Nonsteroidal Anti-inflammatory Drugs ) (Doreen, can you confirm?).

What did you start taking Naproxen for? Because it's an anti-inflammaroty your weight gain seems logical - inflammed tissue retains water (just as when you lift weights you will retain water because muscle tissue is inflammed and torn).

Keep in mind Kodi, that unless you ate upward of an extra 5000 calories it isnt possible to gain 1.5 lbs of fat overnight

Nat