According to recent findings, there are distinct biological mechanisms at play for pain relief in men and women, potentially clarifying why our strongest pain medications often show limited effectiveness in women.
A fresh study conducted by researchers at the University of California San Diego School of Medicine highlights the differing biological systems men and women use to manage pain, particularly in the context of chronic lower back pain and meditation. The research reveals that while men use the body’s natural painkillers, known as endogenous opioids, to alleviate pain, women depend on alternative, non-opioid routes.
Synthetic opioids, which include drugs like morphine and fentanyl, represent the most potent category of pain relief medications available. Studies have shown that women generally have a lesser response to opioids, which function by binding to the same receptors as the body’s natural opioids. This characteristic of opioid medications explains their effective pain-relieving capabilities, as well as their high potential for dependence and addiction.
“Dependence often occurs when individuals start increasing their opioid dosage because the initial amount no longer alleviates their pain,” explained Fadel Zeidan, Ph.D., a professor of anesthesiology and an Endowed Professor in Empathy and Compassion Research at UC San Diego’s Sanford Institute for Empathy and Compassion. “While still a hypothesis, our research implies that one reason why women may have higher rates of opioid addiction could be that they are biologically less responsive to these drugs, forcing them to consume higher doses for any noticeable pain relief.”
The investigation analyzed data from two clinical trials comprising 98 participants, which included both healthy individuals and those experiencing chronic lower back pain. Each participant engaged in a meditation training session, followed by practicing meditation while being administered either a placebo or a high dose of naloxone, a medication that blocks the effect of both synthetic and natural opioids. During this, they were subjected to a painful yet harmless heat stimulus on the back of their leg. The study aimed to evaluate and contrast the level of pain relief achieved through meditation when the opioid system was either blocked or functioning.
The findings revealed:
- In men, blocking the opioid system with naloxone reduced the pain relief gained from meditation, indicating their dependence on endogenous opioids for pain alleviation.
- In women, naloxone actually enhanced the pain relief from meditation, implying a reliance on non-opioid methods for pain reduction.
- Individuals suffering from chronic pain reported greater pain relief from meditation compared to healthy individuals, regardless of gender.
“The outcomes of this research highlight the necessity for more gender-specific pain management strategies, as many common treatments are significantly less effective for women than for men,” Zeidan remarked.
The researchers advocate that customizing pain relief approaches based on a person’s sex could lead to better patient outcomes and minimize the risk of opioid misuse and dependency.
“There are evident disparities in pain management between genders, and prior to this study, we hadn’t identified a clear biological variance in their natural systems,” noted Zeidan. “This research offers the first solid evidence that sex-based differences in pain processing are valid and should be prioritized in the development and administration of pain treatments.”
Co-authors of the study include Jon Dean, Mikaila Reyes, Lora Khatib, Gabriel Riegner, Nailea Gonzalez, Julia Birenbaum, and Krishan Chakravarthy from UC San Diego, Valeria Oliva from Istituto Superiore di Sanità, Grace Posey at Tulane University School of Medicine, Jason Collier, and Rebecca Wells from Wake Forest University School of Medicine, Burel Goodin from Washington University in St. Louis, and Roger Fillingim from the University of Florida.
This research received partial funding from the National Center for Complementary and Integrative Health (grants R21-AT010352, R01-AT009693, R01-AT011502) and the National Center for Advancing Translational Sciences (UL1TR001442).
