MY LOWER BACK WAS DIAGNOSED AS SPONDOLYSIS AND THE ORTHO PRESCRIBED HIFENAC-P TABLETS (100mg/500mg) TWICE A DAY FOR ONE WEEK. HOWEVER, A FRIEND OF MINE WHO IS A GP ADVICES CAUTION AS HIFENAC CAN CAUSE RENAL FAILURE. I WOULD BE GRATEFUL FOR YOUR VIEWS ON THIS. I AM 75 AND A DIABETIC. I TAKE THE FOLLOWING MEDICATION: GLYNASE TWICE A DAY), METFORMIN 500 mg ONCE A DAY, ATORVASTATIN 10 MG ONCE A DAY, RAMIPRIL 5 ONCE A DAY ABD BETALOC 25 ONCE DAILY. mY MOST RECENT HBA1C READING IS 6.6%.