We often use a mixture of Metizol (Pyralgin) 5 g + Tramadol 0,5 g + Metoclopramid 10 mg, supplemented with Nacl 0,9% (up to the volume of 50 ml), as an iv infusion (with the speed 2-3 ml / h). The results are astonishing - a lot of our patients (after the nephrectomia, amputatio uteri) are unresponsive to pain, with the NRS 1-2/10 points. Of course, we use these drugs 30 min before the end of the operation, sometimes preceded with the 5 ml bolus. Do You use any other iv infusions, which are the combination of several, useful drugs? 

Have You ever used Ketamine for preemptive analgesia? Sometime ago I read an article about it - it was told to use Ketamine up to three times, with the overall dose of 0,45 mg/kg given iv. I have tried to do this once and the result was great. What are Your opinions?