Opioid Induced Hyperalgesia (OIH)

General features:

(1) A patient on chronic opioid therapy, typically morphine.

(2) The person experiences a worsening of pain or the onset of new pain symptoms which cannot be explained by disease progression.

(3) Increasing the opioid dose makes the pain worse.

(4) Switching the patient from the opioid to an alternative agent results in a significant pain reduction.

This reaction is different than tolerance, in which higher doses of opioid may be required to achieve the same level of pain control.