I have decreased kidney function. i require anti-inflammatory rx strength drugs. which is better choice for my kidneys? nsaids or corticosteroids?

It depends ..: Ideally you should minimize your use of NSAIDs in the setting of renal dysfunction but physicians are usually a bit more liberal about using some low( to a most moderate) dose NSAIDs with mild chronic kidney disease. Steroids may be better for your kidneys but have their adverse effects too - think fluid retention, elevated sugars, anxiety provoking, worsening blood pressures, increased appetite.

Loaded...: You need to discuss your current medication regimen with a Nephrologist (kidney specialist) or qualified Internist or Family Physician. The Lamictal may be causing aches and pains in and of itself. And it may also affect kidney function. I don't think I would recommend any intervention (NSAID, Corticosteroid) until your medical history is fully taken into account.