A wonderful device for patients who have gone through painful operations such as total hip replacement. A machine is hooked up to an intravenous drip. A button is attached to that machine and strapped to the side of your bed, or to your wrist. When you push the button, you get a small dose of morphine into the drip. The machine then activates a timer so that even if you push the button again within a certain time period (around 8 minutes), you don't get any more drugs.

Patients are usually on the pump for two days or less post-op. Because the doses are smaller there is less tendency to become addicted to the morphine.