What Are The Side Effects Of Microcid SR?

Hi doctor, my boyfriend has been prescribed Microcid SR for severe backache. He has three slipped discs (at the lower part of the spine), but his doctor is not convinced that this is the cause of the extreme pain, and has asked him to have a blood test done. What exactly does Microcid SR do? Is it simply a painkiller or does it have any curative effects? What are its side-effects?