I started taking Allegra at 8 p.m. on April 8, 2003, for seasonal...

I started taking Allegra at 8 p.m. on April 8, 2003, for seasonal sinus problems here in Michigan. After taking the second caplet at the same time the following evening (April 9), I awoke the next morning with a lower back ache. On April 10, after my third Allegra, the back pain was so severe I could not stand from a sitting position without assistance. By my fourth Allegra caplet on April 11, I also had a severe headache along with the increasing back pain. I had taken Allegra for approximately one week before I saw a local television ad for the medication stating that "possible" side effects included headache, cold symptoms and/or backache. I thought then that the possibility of the back pain being related to the Allegra was evident. I discontinued taking Allegra on April 15, 2003, and the backache is nearly gone. The slight headache remains, but responds to aspirin. It should be noted that I had a problem several years ago with Allegra-D causing severe head congestion and sinus pain. I would not recommend anyone taking this medication without knowing that the side effects are more than just "possible" .