Alternatives to Naproxen

I have idiopathic complex Parkinson's disease, using an apomorphine pump and Sastravi 150 x5 & 125 x2 daily. Due DBS surgery Aug / Sep 2017. Recent blood test has highlighted that I am anaemic. I have been on Naproxen 500 mg x2 daily for the last 5+ years plus due to arthritis in all my joints, specifically my left knee which has been assessed as requiring a total knee replacement, appointment with medical team in July. GP advised stopping taking the Naporxen and I am awaiting an endoscopy. 

Has any one been prescribed a drug as an alternative to Naproxen that is not so hard on the stomach?