Intense chronic abdominal pain: could morphine be the culprit?

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The Narcotic Bowel Syndrome (NBS) represents a paradoxical complication linked to the prolonged use of opioid medications.

Although these substances are prescribed to relieve pain, in the long term, they can cause increased abdominal pain and intestinal functional disorders.

This phenomenon, often unknown to both patients and health professionals, requires special attention due to its significant impact on quality of life.

Symptoms can include:

  • chronic abdominal pain ;
  • bloating ;
  • severe constipation ;
  • or even a marked slowdown in intestinal transit.

Awareness of these symptoms is crucial for users of narcotics such as morphine and oxycodone, to allow early recognition of the syndrome and avoid worsening of symptoms.

Understanding the causes

The origin of NBS is related to the complex interaction between opioids and the digestive system.

Opioids act on mu receptors present in the brain but also in the intestine, where they can slow peristalsis and affect nutrient absorption, leading to an alteration of intestinal function.

Dependence and tolerance to opioids also contribute to the complexity of the syndrome, requiring increasingly higher doses to relieve pain, which exacerbates the symptoms of NBS.

Opioid-induced hyperalgesia: a paradoxical increase in pain

Opioid-induced hyperalgesia, or central morphine hyperalgesia, is a phenomenon by which the use of opioid medications, such as morphine, can paradoxically increase pain sensitivity in some individuals.

This phenomenon may seem counterintuitive because opioids are primarily used for their ability to relieve pain.

However, in some cases, instead of decreasing pain, opioids can make it more intense.

Mechanism: The exact mechanism of opioid-induced hyperalgesia is not fully understood, but it involves changes in the central nervous system. Prolonged or high-dose use of opioids can lead to changes in how the brain perceives pain. In particular, it can alter the pathways and nerve receptors involved in pain transmission, making the nervous system more reactive or sensitive to pain signals.

Manifestations: People suffering from opioid hyperalgesia may notice that their pain threshold decreases — meaning they experience pain from stimuli that were not painful before. Moreover, the pain may seem to spread or become more diffuse, and not remain localized to the initial area of pain or injury.

Distinguishing from Other Phenomena: It is important to distinguish opioid-induced hyperalgesia from opioid tolerance. Tolerance develops when the body becomes accustomed to a certain dose of an opioid, requiring higher doses to achieve the same analgesic effect. Hyperalgesia, on the other hand, specifically refers to an increased sensitivity to pain.

Management: Managing opioid-induced hyperalgesia can be complex. It may require a reevaluation of the pain management regimen, including gradually reducing the dose of opioids, switching to other types of pain medications, or using non-drug methods to manage pain, such as physical therapy, cognitive-behavioral therapy, and other integrative medicine approaches.

Central morphine hyperalgesia underscores the importance of careful and monitored use of opioids, highlighting the need for personalized approaches in chronic pain treatment to avoid adverse effects that could worsen the patient’s condition.

The chirality of opiates: understanding the impact of levorotary and dextrorotary forms

The concept of chirality, defining molecules as levorotary or dextrorotary based on their ability to deviate light, plays a crucial role in the efficacy and side effects of opioid medications.

This distinction, at the heart of modern pharmacology, directly influences the interaction between opiates and the body’s opioid receptors.

The spatial configuration of an opiate, whether levorotary or dextrorotary, determines its affinity for opioid receptors, thereby modulating its analgesic potential as well as its side effect profile. Thus, understanding and exploiting this chemical property allows for the optimization of treatments for maximum efficacy while reducing associated risks.

Wikipedia image. At the Heart of Morphine: chirality as the key to differences between relief and suffering.
Wikipedia image. At the Heart of Morphine: chirality as the key to differences between relief and suffering.

Notable examples, such as methadone, highlight the importance of selecting the specific form of an opiate to improve therapeutic outcomes. Methadone, used both for its analgesic properties and in opioid detoxification, exhibits different effects depending on its chirality, underscoring the importance of ongoing research in this area.

This in-depth knowledge of chirality principles applied to opiates paves the way for more targeted treatment strategies, enabling healthcare professionals to offer personalized and safer care to patients requiring opioid therapies.

Nociceptors and interaction with morphine: a painful perspective

Nociceptors, sensory receptors specialized in detecting painful stimuli, play a crucial role in our perception of pain. They transmit signals from body areas exposed to potential damage to the central nervous system, where these signals are interpreted as pain. Morphine, a powerful opioid analgesic, intervenes by modulating the activity of these nociceptors and pain pathways in the brain and spinal cord.

Picture from : now.aapmr.org. At the heart of pain modulation: discover how morphine influences nociceptors to alleviate suffering
Picture from : now.aapmr.org. At the heart of pain modulation: discover how morphine influences nociceptors to alleviate suffering

By binding to opioid receptors located in the central and peripheral nervous system, morphine can effectively decrease the transmission of pain signals emitted by nociceptors. This results in a reduction in the perception of pain, thus providing significant relief to individuals suffering from acute or chronic pain. However, this interaction does not come without complications.

Prolonged use of morphine can lead to changes in the functioning of nociceptors and opioid receptors, causing increased sensitivity to pain, a phenomenon known as opioid-induced hyperalgesia. Paradoxically, although morphine is used to alleviate pain, its long-term consumption can make receptors more reactive to painful stimuli, thereby increasing the intensity of pain experienced.

Understanding the interaction between nociceptors and morphine is essential for optimizing the use of opioid analgesics while minimizing the risks of negative side effects. This underscores the importance of well-balanced pain management approaches that consider both the immediate benefits of pain relief and the potential long-term impacts on pain sensitivity.

Testimonies and expert opinions

Patient stories experiencing NBS highlight the importance of quick recognition of the condition.

The frequency of this syndrome (estimated at 1-2% of the treated population) is increasing due to the more frequent use of morphine or derivatives for treating various types of pain, post-surgical or not. Study from the JFHOD, Francophone Days of Hepato-gastroenterology and Digestive Oncology, the francophone reference congress for digestive diseases and cancers. Study from the JFHOD, Francophone Days of Hepato-gastroenterology and Digestive Oncology, the francophone reference congress for digestive diseases and cancers.

Dr. Corentin Lacroix, a general practitioner and author of the WhyDoc blog who has personally experienced this disorder, enlightens us in a fun video on the pains and the impact on quality of life that narcotics or opiates such as morphine can cause.

Video from the WhyDoc Blog. Dr. Corentin Lacroix is registered with the RPPS. It is the reference directory for professionals working in the healthcare system.

It took me years to understand that my intestinal pains were linked to the medications I was taking for an entirely different pain A patient

opioid withdrawal under medical supervision, accompanied by pain management with non-opioid alternatives. A gastroenterologist specialized in treating NBS

Which Symptoms to Monitor?
Identifying the symptoms of NBS is a key step towards a correct diagnosis.

The main signs to monitor include: chronic abdominal pain, severe constipation, nausea, and a general sense of malaise.

These symptoms can worsen with the increase in opioid doses.

It is essential for narcotic users to be attentive to these signals and consult a health professional if in doubt.

An early diagnosis can allow for better management of symptoms and prevent complications.

Preventing and managing NBS


Prevention of NBS involves careful and controlled use of opioids, favoring alternative approaches to pain management when possible. Strategies such as physiotherapy, meditation, or acupuncture can be explored.

In case of NBS symptoms, consulting a specialist for a comprehensive evaluation is crucial.

Opioid withdrawal, although it can be difficult, is often necessary to alleviate symptoms.

Professional Information Sources on Narcotic Bowel Syndrome


For those looking to deepen their understanding of narcotic bowel syndrome, several professional resources are available.

From medical journals to online databases, there is a range of options for health professionals wishing to stay informed of the latest research and practical recommendations.

Specialized medical associations, such as the French Association of Gastroenterology or the American Gastroenterological Association, regularly publish updates and guides on managing side effects related to opioids, including NBS.

Narcotic bowel syndrome is characterized by the onset and worsening of abdominal pain in patients taking opioids chronically, leading to an increase in morphine doses which causes an increase in digestive symptoms.

Abdominal pain is often severe to very severe and must occur daily for at least 3 months.

There are often other digestive symptoms associated as consequences of chronic morphine use such as nausea, vomiting, constipation, bloating.

It is estimated that about 5% of patients on long-term morphine develop narcotic bowel syndrome.

The main pathophysiological mechanism is the induction of a central hyperalgesia phenomenon by morphine.

Therapeutic management includes a significant part of therapeutic education by explaining to patients the harmful role of morphine, rotating molecules with a gradual decrease to try to achieve withdrawal associated with antidepressants and/or anxiolytics.

Morphine peripheral receptor antagonist molecules (PAMORA), such as naloxegol, do not seem useful for managing the painful component. Excerpt from the site: studocu.com. Towards better management of Narcotic Bowel Syndrome: the contributions of Dr. Benoit Coffin, hepatogastroenterologist.

Furthermore, academic platforms such as PubMed and ScienceDirect provide access to case studies, systematic reviews, and meta-analyses dedicated to the impact of narcotics on the digestive system.

For practitioners and researchers, these resources constitute a valuable mine of information for developing effective and personalized management strategies.

Narcotic bowel syndrome is a striking example of the importance of a balanced approach in prescribing and using opioids.

By informing patients and health professionals about its symptoms and causes, it is hoped to reduce the incidence of this syndrome and improve the quality of life for those affected.

Ongoing research in this field promises to develop more effective management strategies and provide safe alternatives to chronic pain management, thus reducing the use of narcotics and associated risks.

This awareness not only helps individuals in diagnostic limbo but also opens the way for broader discussions on the safe use of opioid medications and innovative approaches to pain treatment.

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