Opioids and Hyperalgesia

Opioids and Hyperalgesia

If you have ever encountered severe pain, then you know that the most important thing to you is to find a way to make it stop. For chronic pain sufferers who endure similar discomfort on a regular basis, stopping the pain is even more of a priority.  That is why, for millions of Americans struggling with ongoing pain, the most common medical response is opioid medications.

Despite the spotlight on the opioid crisis with its thousands of fatalities, Americans are still consuming these addictive compounds at alarming rates. In 2016, more than 214 million opioid prescriptions were filled, or almost 66.5 per 100 people. That means almost one in five Americans is on opioid medications.

The risk for opioid abuse is naturally quite high with this many people on the powerful class of narcotics.  It is estimated that at least 11 million Americans abused opioid drugs.  This resulted in more than a thousand emergency room visits daily due to opioid misuse.  In 2016, more than 40,000 Americans died from opioid abuse.

How Opioids Affect You

Opioids are a class of compounds that include street drugs like heroin and fentanyl as well as medically  prescribed drugs like codeine and morphine. Some of these compounds are derived from naturally occurring materials while others are chemically synthesized, but their original source does not alter how they act upon the human body.

Opioids interact with the opiate receptors on nerve cells in the brain. By blocking these nerves, it interrupts the transmission of pain impulses to the brain. However, ongoing use of opioids has serious consequences.  Prolonged opioid use can actually re-wire the brain, making you physically and emotionally dependent upon them.  In other words, you become incapable of functioning without them.

In addition to the addictive qualities of opioids, these drugs also produce a number of other physiological changes.

• Slows digestion
• Induces nausea and constipation
• Reduces physical coordination
• Damages organs
• Impairs breathing and oxygen circulation

Opioid-induced Hyperalgesia

Much of the opioid abuse that occurs might be avoided if patients and doctors better understood the effects that these powerful compounds have on those taking them. Although all doctors have some training in how to manage opioid use, most do not possess the extensive knowledge necessary to avoid serious risks.

One of the most overlooked aspects of opioid use is opioid-induced hyperalgesia. Opioid-induced hyperalgesia is a condition in which your nerves actually become more sensitive to pain due to opioid use. In effect, opioids may dull pain initially, but it quickly loses efficacy as your pain receptors grow more responsive to nerve impulses. Actually increasing the dosing strength amplifies symptom intensity.

It can be difficult to distinguish between opioid-induced hyperalgesia and similar conditions like dependency, drug tolerance and disease progression, so opioid-induced hyperalgesia is often overlooked as a possibility. That is one of the reasons why there are no accurate numbers on how many opioid users suffer from opioid-induced hyperalgesia.

This, however, should not mean that health care providers should underestimate the pitfalls of opioid use.  If more physicians understood that opioids may actually worsen pain conditions, then it might deter more frivolous prescribing.

The Cause of Opioid-induced Hyperalgesia

Although research into opioid-induced hyperalgesia is ongoing, a popular theory of the cause of this condition is that opioids act on NMDA receptors found on pain neurons. When this agonistic action occurs, it excites the neuron, making it more likely to release substance P and other pain-inducing neurotransmitters.

This theory is not yet proven, but there is strong evidence supporting it.  Studies show that when a NMDA antagonist is present to block the action of the opioid, opioid-induced hyperalgesia is diminished. Furthermore, when an opioid antagonist like naloxone is used, the effects of opioid-induced hyperalgesia actually worsened, suggesting that more displaced opioid molecules interacted with NMDA receptors.

Treating Opioid-induced Hyperalgesia

Once your physician diagnoses you with opioid-induced hyperalgesia, there are several treatment options.  The most obvious, of course, is to discontinue the use of the opioid medication, but this should be done gradually, since an abrupt stoppage may worsen the opioid-induced hyperalgesia. There is also the possibility that there may be withdrawal symptoms that a graduated withdrawal would ease.

However, if there is ongoing, severe pain that the opioids may be remedying, then stoppage may not be possible. In those cases, it may be incumbent upon the presiding physician to modulate the opioid dosage strength until the analgesic and hyperalgesic properties are acceptably balanced.

In some circumstances, clinicians have found that using an opioid not from the phenanthrene class that includes morphine and codeine may avoid severe opioid-induced hyperalgesia. Alternatives that may ease OIH symptoms include fentanyl, methadone or buprenorphine.

Finally, clinicians may wish to consider treating patients with opioid-induced hyperalgesia also with a COX-2 inhibitor.  COX-2 inhibitors can block opioids from binding NMDA receptors. These compounds also inhibit pain symptoms and may be sufficient to replace opioid pain killers for some patients.

Alternatives to Opioid Pain Killers

Although some patients will require opioid-strength medications to manage their pain, many may find that alternative pain management techniques are just as effective.  These may include

• NSAIDs– Nonsteroidal anti-inflammatoriesdrugs like Advil or Motrin may have enough pain killing potency to nullify pain in some patients.  Many pain conditions that involve painful swelling respond well to NSAIDs.  Some studies show that NSAIDs may be as powerful as opioids for some patients.
• Massage therapy—manual manipulation of muscles and joints has some potent pain killing properties.  Not only does this stimulate endorphin—natural pain killers—production, but it also relaxes tense muscles which can produce pain on their own.
• Exercise—another important way to produce endorphins is to engage in some exercise.  Before you embark on a new fitness program discuss it with your physician so that you don’t injure or strain yourself.
• Meditation—you may initially dismiss the idea of managing your pain with meditation, but there is a reason this practice has endured for centuries. Just a few sessions may be enough to improve your pain intensity.

Article written by: Dr. Robert Moghim – CEO/Founder Colorado Pain Care

M.D. Disclaimer: The views expressed in this article are the personal views of Robert Moghim, M.D. and do not necessarily represent and are not intended to represent the views of the company or its employees.  The information contained in this article does not constitute medical advice, nor does reading or accessing this information create a patient-provider relationship.  Comments that you post will be shared with all visitors to this page. The comment feature is not governed by HIPAA and you should not post any of your private health information.