After I underwent the procedure for preparations for a dental crown, I experieinced bad headaches, earache and my many teeth would ache bably out of the blue. I took ultracet last night and my pain went away. However, about an hour after taking it, I felt dizzy, spacey, and then felt extreme sleepiness. Here it is, the next morning, I am at work, and I still feel a bit out of it. Glad it can relieve my pain but not sure if I want to experienced these side effects again.