Why do I sometimes need to increase the dose of pain medication to get the same effect?

Why do I sometimes need to increase the dose of pain medication to get the same effect?

Marc Darrow (Physical Medicine and Rehabilitation, Joint Rehabilitation Sports Medical Center, Inc. ) gives expert video advice on: Are narcotics safe and effective for managing chronic pain?; Is there a danger of addiction when using narcotic medicine for pain? and more...

The question always arises, why do you need to take more and more of the same medication that used to work before? Now you are taking five times as much. But the answer is very simple. We have receptors in the body and in the brain that accept these chemicals, and as we take more and more of it, these receptor sites will shut down. Then we have to use more and more of the medication to fill up those receptor sites and stimulate them to have the effects that are needed.