I,ve been taking diclofenac sodium 75mg for over 10 years and for the last 5/6 years, lansoprazol. are there any alternatives?

Depends: There are safer alternatives for reflux and joint pain, but I need to know why specifically you are taking those medications..

Yes many: Diclofenac is in the same class of drugs like ibuprofen and narpoxen (Motrin , Alleve, etc.). Lansoprazole (prevacid) is a proton pump inhibitor in the same class as protonix, nexium, (esomeprazole) etc. The choice of agent(s) may be affected by your individual tolerance to the drug(s), adverse events, cost, etc. If you feel that a change may be necessary, talk it over with your physician before doing anything.