As many readers know, I am receiving 80 mg injections of depo-medrol each week for PMR. Depo-medrol comes in three strengths: 80 mg per ml, 40 mg per ml and 20 mg per ml. My primary care physician (PCP) in New Jersey chose to administer 1 ml of the 80 mg strength and while the injection was virtually painless, I experienced a deep throbbing ache in my caboose on days 2, 3, and 4. Though it was tolerable, it bothered me when I bent over or sat down. When I visited my vacation home in New York’s Adirondack region, I went to a nearby clinic for the injections. By chance, the PA (physician assistant) who administered these injections used 2 ml of the 40 mg strength serum and there was no subsequent injection site pain. Now that my PCP has changed his order to this regimen, I experience no more discomfort. A friend who is a pharmacologist speculated that the higher concentration of active ingredient in the 80 mg strength is more irritating to the tissues, thus the pain. I hope this information will be of help to someone who is being treated with depo-medrol, or gets injections for the control of flares.