I feel strange things going on in my head and body, but pain still bad. I took 1/2 of the 50 mg tablet more than 10 minutes ago [20 mins?]. I guess I have to take the other 1/2 now. I thought I had read that Demerol worked fast, but didn't last long. Maybe I am mistaken. I take Restoril at night for sleep, so I hope the demerol is safe for me to take before bed, too.