Can pain medicine make you worse? Understanding opioid-induced hyperalgesia

Many people with chronic pain take daily medication to manage their suffering.  The most commonly used medications are opioids, otherwise known as narcotics.  While a large percentage of those using opioids improve with treatment, some do not- and others get worse.

There are many potential causes for this worsening.  Progression of the underlying painful disease, new or worsening depression and tolerance to pain medications are among the most likely.  Another concern is opioid-induced hyperalgesia.

To understand this controversial problem, one must first understand how the body processes pain.  Normally the body sends pain signals to the brain and the brain sends signals back to block the pain.  A balance exists between pain causing and pain blocking activity in the nervous system.  Sometimes this system fails, though, such as in the case of fibromyalgia.  A major cause of fibromyalgia is inadequate activity of the pain blocking system.

Scientists have long known that opioids can disrupt this balance as well.  The most definite studies are in animals given continuous narcotics.  These animals develop more pain causing and less pain blocking nerve activity over time.

Whether this effect occurs in humans, though, has been controversial.  It appears after much research that an imbalance in the pain processing system (opioid-induced hyperalgesia) can happen in those who take regular opioids.

Since many potential causes exist for increased pain in those taking narcotics, how do you know that opioid-induced hyperalgesia is the problem?  Several steps (under the supervision of your doctor, of course) may help:
1. Make sure there is not a change in the disease causing the pain.
2. Make sure other factors such as stress, anxiety and/or depression are not increasing the pain.
3. Try increasing the dosage of the opioid to see if tolerance is the problem.
4. Consider increasing the dosage again.
If the above steps do not identify a cause or improve the pain, then opioid-induced hyperalgesia is a reasonable concern.

Optimal treatment of this problem is unclear.  Some experts recommend changing to a different opioid.  Others recommend other types of pain medications.  Still others advocate stopping the medication through a detoxification process.  What is clear is that treatment requires an open and honest conversation with your pain management physician.

For more information, try this textbook entry: http://books.google.com/books?hl=en&lr=&id=ZwPIjKg0XukC&oi=fnd&pg=PA171&dq=opioid-induced+hyperalgesia&ots=J7dVhl5IfK&sig=1HsBXpLRwrROVMicTc2nMTicdao#v=onepage&q=opioid-induced%20hyperalgesia&f=false.