Tag: pain management

Patient Awake for 13 Minutes During Surgery

A patient in the US was awake for 13 minutes of his surgery because apparently his anaesthetic was never turned on.

In mid-2020 the patient, Matthew Caswell went into Progress West Hospital in O’Fallon, Missouri, for hernia repair and removal of a lipoma on the back of his neck.

However, he soon became aware that something was amiss.

“I knew I was in trouble when I felt the cold iodine hit my belly and they were scrubbing me off. At any second I was waiting to go out, but all of a sudden I just got stabbed in my stomach,” Caswell told local TV station KCTV.

Caswell’s lawyer Kenneth Vuylsteke told MedPage Today that a paralytic agent had already been given to his client, and then the mask was put on to receive sevoflurane for general anaesthesia, but the flow of the gas was never started.

Caswell able to feel pain and hear operating room conversation for 13 minutes, he told KCTV.

During this, his vital signs surged, said Vuylsteke. Records shared with MedPage Today show a baseline heart rate in the 65 to 70 range, which skyrocketed to 115 beats per minute within a few minutes of the first incision.

After the first incision, Caswell’s blood pressure also shot up, from a baseline of 113/73 mm Hg to 158/113 mm Hg — severe hypertension.

Vuylsteke noted that hat should have been ample warning that something was likely wrong with the anaesthetic.

What he gathered so far is that Caswell was brought into the operating room and given the paralytic agent. The anaesthesiologist or the nurse anesthetist put the anaesthetic mask on him, but then the surgeon requested to see the lipoma before starting.

Caswell was turned over so the surgeon could see the lipoma. He was then put onto his back again, and the mask was put back on, but the sevoflurane was never turned on, Vuylsteke said.

A “Significant Event Note” is in hospital records that acknowledges that a “review of the anesthetic record demonstrates a delay in initiating inhalational anesthetic after induction of anesthesia.”

The note indicates that Caswell and his mother were “immediately informed regarding the delay in initiating the inhaled anesthetic agent until after the start of the surgical procedure.” The hospital “provided emotional support and discussed our intention to ensure his pain and anxiety over the event were well controlled in the immediate term.” The hospital also recommended a psychology consult for which they would cover the cost.

Caswell charges that he’s suffering from post-traumatic stress disorder and panic attacks because of the experience.

He’s suing the anaesthesiologist, the nurse anaesthetist Kathleen and also their employer, Washington University in St Louis.

“I would have rather died on that table,” he told KCTV.

Source: MedPage Today

Cannabis Use Screening in Older People Urged

Cannabis plants. Photo by Harrison Haines from Pexels

Older people who use cannabis to relieve or treat health conditions generally don’t discuss their substance use with doctors, according to a new study. 

In this study of over 17 000 people aged 50 and over in the US, some use cannabis daily and others have mental health problems. The findings were published in peer-reviewed The American Journal of Drug and Alcohol Abuse.

The research is the first to identify where older users obtain cannabis, with the majority saying obtaining it was easy. Those who use cannabis for health reasons are more likely than non-medical (recreational) users to buy it at a medical dispensary (20% vs 5%) and less likely to get it for free (25% vs 46%) or from other sources such as parties (49% vs 56%).

According to the authors, the findings have significant clinical and policy implications especially as more US states are legalising cannabis, which is leading to a rapid rise in uptake among older people. This has implications for other countries such as South Africa, which has recently decriminalised it for personal use.

They urge that doctors should be routinely screening older people for cannabis and other substance use, as well as checking cannabis users for mental health problems, and recommending treatment when necessary. They add that education on the risks of obtaining cannabis and cannabis products from unregulated sources is also vital for this group.

“Cannabis is readily available and accessible to older cannabis users for medical or non-medical purposes,” said Namkee G Choi from University of Texas.

“The findings suggest that some medical users may be self-treating without healthcare professional consultation.

“All older people who take cannabis should consult healthcare professionals about their use. As part of routine care, healthcare professionals should screen for cannabis and other substance use, and for mental health problems.

“They should also recommend services or treatment when indicated. Given the increase in THC (tetrahydrocannabinol) potency, healthcare professionals should educate older cannabis users, especially high-frequency users, on potential safety issues and adverse effects.”

THC content has increased significantly over the past decades. Since 1995, the potency of illicit cannabis plant material seized in the US has consistently increased over time, from approximately 4% in 1995 to approximately 12% in 2014. Among older US adults, cannabis has more than doubled between 2008 and 2019. Reasons include pain relief and treating health issues. However, not much is known about where they obtain cannabis and how much they discuss their use with doctors.

Data for the research was drawn responses from the 2018 and 2019 National Survey on Drug Use and Health (NSDUH), with 17 685 men and women aged 50 and older. This annual national survey measures substance use and misuse and mental illness across the US.

The researchers analysed responses including those on frequency of cannabis use, reasons for taking it, where it was obtained, and how much they utilised healthcare services.

The study found that, overall, 9% used cannabis over the past year and of these, 19% used cannabis for a medical purpose to some extent, eg, to treat chronic pain, depression or diseases like arthritis, while the rest (81%) were recreational (non-medical) users.

The authors also found that people who reported cannabis use as being for medical reasons were over four times as likely than non-medical users to discuss their use with a healthcare professional. Nevertheless, only a minority of medical users did so, which implies that some are self-treating without consulting a doctor.

Medical users were also more likely than non-medical users to more frequently take cannabis, with 40% using it between 200 and 365 days a year.

A higher proportion of older cannabis users had mental illness, alcohol use disorder, and nicotine dependence compared with non-users of the same age, although medical users were less likely to have alcohol problems compared to recreational users.

As well as calling on doctors to do more, the study authors say the NSDUH needs updating to “reflect changing cannabis product commercialization”, such as including products available to older people like cannabidiols, topical solutions and edibles.

Limitations of the study included the relatively small number of medical users and the fact some respondents may have under-reported their cannabis and other substance use.

Source: Medical Xpress

Journal information: The American Journal of Drug and Alcohol Abuse, www.tandfonline.com/doi/full/1 … 0952990.2021.1908318

Timing is Key for Psychological Treatment of Chronic Pain

When timed correctly, psychological interventions can reduce the risk of chronic pain, according to a pain expert at the virtual 2021 American Academy of Pain Medicine annual meeting.

“We can look at chronic pain as occurring in a very linear process,” said Ravi Prasad, PhD, of University of California Davis, in a meeting session about multimodal ways to prevent chronic post-surgical pain.

“By definition, pain starts off as something acute,” Dr Prasad explained. The acute phase includes assessments and treatment to try to eliminate pain quickly.

“When the pain condition fails to respond to some of these initial treatments, it starts to enter the subacute category,” Dr Prasad continued. “The patient is still engaged in different medical workups to try to identify the cause of the pain and still participating in treatments, but they haven’t responded to the interventions in the manner expected, meaning the pain continues to persist.” Normally, this comes some 3 to 6 months after the acute phase.

Pain can become chronic when it has plateaued and resists medical treatment for at least 6 months.

“It’s important to recognize these time points exist,” Dr Prasad emphasised. “We can intervene at these different points — and intervene even prior to the experience of acute pain — to try to minimize the likelihood that persistent pain develops.”

There are many factors which contribute to chronic pain. These include environmental stressors, lifestyle factors, unhealthy support systems, limited care access, and patient risk factors such as substance abuse history, adverse childhood experiences, and psychiatric conditions.

Research has shown the most useful predictors of poor pain outcomes after surgery were pre-surgical somatization, depression, anxiety, and poor coping.

“All of these are things that are actually modifiable,” Prasad said. “We can actually do something about these to change the outcomes a person might have.”

Cognitive therapies and relaxation training are two interventions receiving a lot of attention, he noted. Breathing, relaxation exercises, and meditative practices can help patients learn to quiet the nervous system by working on the sympathetic-parasympathetic axis. But cognitive processes also have to be targeted, Prasad observed, and “this is where cognitive behavioral therapy can come in.”

Cognitive behavioural theory is premised on the idea that “by changing the interpretation, we can change the impact of consequences at the emotional, physical, and behavioral level,” Dr Prasad said. “The challenge with this is that our interpretations tend to be automatic.”

“Making changes in our interpretation is difficult because we have to become aware of processes that are occurring in our subconscious and make changes in something that’s been with us for a very long period of time,” he acknowledged. “These thought processes can be very resistant to change. But it’s essential we do this if we want to have sustained change in our outcomes.”

It’s not something as simple as turning negative thoughts into positive ones, Prasad added. “Rather, we look at the accuracy and the degree of helpfulness of the thoughts, and modify the thoughts into something that is more accurate and helpful.”

“We know that when people engage in cognitive behavioral therapy, their outcomes are improved. Affective stress is decreased, pain sensitivity decreases, and this can minimize opioid burden,” he continued. He added that there are many psychological-based tools backed by a strong evidence basem including biofeedback training and mindfulness-based stress reduction.

Dr Prasad emphasised however that timing of these treatments is essential.

“The way to optimize timing is to do presurgical screening to identify what’s the most appropriate intervention for the patient,” he said. Some patients may need help before surgery, others can be targeted at the acute or subacute phase. “Regardless, we want to make sure we address symptoms as early as possible and not wait for pain to be in a chronic state.

Source: MedPage Today

Presentation information: Prasad R “Psychological Interventions to Reduce of Persistent Pain” AAPM 2021.

Treatment of Lingering COVID Pain is Challenging

The treatment of pain in recovered COVID patients poses unique challenges, said a pain expert presenting at the American Academy of Pain Medicine virtual meeting.

“A lot of these patients are going to need rehabilitation” or physical therapy, noted Natalie Strand, MD, of the Mayo Clinic in Scottsdale, Arizona, at the meeting. “There can be quite a bit of deconditioning that occurs, especially after a prolonged ICU stay. Neuropathic pain is also quite common.”

Post-COVID neuropathy may be viral or else possibly related to patient positioning, including prone positioning. Some patients “may need short-term opioids or gabapentinoids and they may experience aggravation of prior underlying pain, either due to direct physical causes or to the increase in anxiety and depression that can accompany a COVID infection,” Dr Strand said.

A study that followed 143 patients two months after acute COVID showed a high proportion reported persistent symptoms — including fatigue (53%), joint pain, (27%) and chest pain (22%) — that often results in patients going to a pain clinic for care, she noted.

Persistent pain remains prevalent, following any ICU admission, ranging from 28% to 77%, according to Dr Strand.

Chronic neuropathic pain after a COVID patient’s ICU stay can include muscle pain related to joint contractures or muscle atrophy, and pain due to critical illness myopathy or polyneuropathy. In addition, peripheral nerve injuries have been associated with prone positioning for COVID–related acute respiratory distress syndrome, Dr Strand added. Complications from traumatic procedures like placement of chest tubes or tracheotomy can also cause chronic neuropathic pain.

Dr Strand noted that pain can persist after discharge of COVID patients, as indicated by follow-ups. In China, three-quarters of patients previously hospitalised with COVID continued to report at least one symptom 6 months later, with fatigue or muscle weakness by far the most common symptoms (63%). “Compared with 2-month follow up, 6 months later we see the same trends,” she pointed out.

In that study, “13% of the patients who did not develop an acute renal injury during their hospital stay and presented with normal renal function exhibited a decline in GFR at follow up,” Dr Strand noted. This may signal caution about using NSAIDS to manage pain in some patients, she said: “Normal renal function at discharge does not necessarily mean it will remain this way 6 months afterwards.”

There may be a relationship with the SARS-CoV-2 virus and chronic neuropathic pain, Strand observed. In a recent article in Pain Reports, “the authors concluded it could be direct or indirect effects of the virus on the nervous system that can cause neuropathic pain,” she noted. “We know that there are neuropathic symptoms involved with the famous loss of taste and loss of smell with presentation,” she continued. “But also in the acute phase, we commonly see headache, dizziness, muscle pain, ataxia, and in hospitalized patients we see stroke, meningitis, encephalitis, and autoimmune disorders like Guillain-Barré syndrome and acute disseminated encephalomyelitis.”

Psychological stressors can also be related to the emergence of chronic pain, added Dr Strand. “Anxiety and depression often follows COVID-19 infection,” she said. “It may be wise to screen our patients for anxiety and depression after infection to see if we can further control these components to help manage their pain overall.”

Source: MedPage Today

Presentation information: Strand NH “Treating the COVID-Recovered Patient: An Evolving Understanding” AAPM 2021.

Epidurals Do Not Increase Autism Risk for Babies

A Canadian study showed that children born to mothers who used epidural analgesia during labour were not at increased risk of developing autism spectrum disorder (ASD).

Epidural analgesia is administered into the epidural space around the spinal cord, typically during labour. Besides easing pain and reducing the use of other analgesics, it has also been shown to lower cortisol levels, expedite the return of bowel function, decrease the incidence of PE and DVT in the postoperative period, and reduce hospital stays.

Epidural analgesia is used by 73% of pregnant women in the U.S. for pain during labour. Since the US incidence of ASD increased from 0.66% in 2002 to 1.85% in 2016, there have been more efforts to identify environmental factors that put children at risk, the researchers said.

Elizabeth Wall-Wieler, PhD, of the University of Manitoba in Winnipeg, and colleagues drew from population datasets and included vaginal deliveries of singleton babies born in Canada from 2005 to 2016, following children from birth up until 2019.

Of the more than 123 000 infants included in the study, approximately 38% were exposed to epidural analgesia during delivery, and about 80 000 had a sibling in the study cohort. The mean age of mothers was 28 years. The children’s median age at their first diagnosis of ASD was 4 years. Births with epidural analgesia were more likely to be nulliparous or involve other factors such as foetal distress.
About 2.1% of children exposed to epidural labour analgesia (ELA) later developed ASD, compared with 1.7% who were not exposed, the team reported. But after factor adjustments, the researchers found no association between epidural analgesia and childhood ASD risk, they wrote in JAMA Pediatrics.

“This finding is of clinical importance in the context of pregnant women and their obstetric and anesthesia care professionals who are considering ELA during labor,” Dr Wall-Wieler and colleagues noted.

The group’s results contrast with Qiu et al.’s recent study that found a 37% increased risk of autism in children whose mothers used epidural analgesia during their delivery. Their study did not account for key perinatal factors, such as induction of labor, labor dystocia, and foetal distress, and drew criticism from five medical societies for possible residual confounding.

Dr Wall-Wieler and colleagues said that ELA is “recognized as the most effective method of providing labor analgesia,” adding that future qualitative research should assess how their findings — as well as the prior ones — have altered the perceptions about the perceived risk of ASD in offspring among both pregnant women and healthcare providers.

In an accompanying editorial, Gillian Hanley, PhD, of the University of British Columbia in Vancouver, and colleagues said that given the concerns stemming from previous findings, “it thus comes with some relief that Wall-Wieler et al found no association when controlling for key maternal sociodemographic and perinatal factors.”

“Epidural labor analgesia is an extremely effective approach to obstetric analgesia,” Dr Hanley’s group noted. “We have a collective responsibility to understand whether it is a safe option that sets a healthy developmental pathway well into childhood.”

The researchers observed an association between ELA and autism risk before accounting for confounders; but after controlling for all maternal sociodemographic, pre-pregnancy, pregnancy and perinatal factors, there was no longer a correlation.

In an analysis of siblings, researchers again observed a null association after controlling for all confounders and family fixed effects. Siblings who were exposed to epidural analgesia had a 2% cumulative risk of developing autism, and unexposed siblings had a risk of 1.6%.

The accuracy of inpatient and outpatient diagnostic codes for ASD, as well as coding for ELA was acknowledged as a study limitation by the researchers, as well as a lack of data describing epidural analgesia drug doses.

Source: MedPage Today

Journal information: Wall-Wieler E, et al “Association of epidural labor analgesia with offspring risk of autism spectrum disorders” JAMA Pediatr 2021; DOI: 10.1001/jamapediatrics.2021.0376.

Unique Genetic Basis for Chronic Pain in Women Discovered

A meta-analysis of UK genetic data has found a different genetic basis for chronic pain in women compared to men.

While the results are still preliminary, this is one of the largest genetic studies on chronic pain analysing by sexes.

“Our study highlights the importance of considering sex as a biological variable and showed subtle but interesting sex differences in the genetics of chronic pain,” said population geneticist Keira Johnston of the University of Glasgow in Scotland.

Chronic pain conditions are among the most prevalent, disabling, and expensive conditions in public health, and are frequently overlooked for research funding. With 100 million people in chronic pain in the US in 2016, overprescription of opioids for chronic pain has resulted in an epidemic of opioid misuse, with 66% of overdose cases being for opioids. Even very moderate opioid use carries the risk of addiction and abuse.

Even when studies are done, they often overlook underlying sex differences, and that’s a huge and detrimental oversight. Compared to men, women are far more likely to develop multiple chronic pain disorders, and yet historically, 80 percent of all pain studies have been conducted on male mice or male humans. This means we know very little about how and why females are suffering more and what treatments can help them best.

While there are probably multiple biological and psychosocial processes in this sex discrepancy, the current genome-wide study suggests there’s a genetic factor in the mix, too.

The researchers compared gene variants associated with chronic pain in 209 093 women and 178 556 men from the UK Biobank, and found 31 genes associated with chronic pain in women and 37 genes associated with chronic pain in men with barely any overlap. This might be due to the slightly smaller sample size of men but the results are nonetheless intriguing, the researchers maintained.

The vast majority of these genes were active in a cluster of nerves within the spinal cord, known as the dorsal root ganglion, which transmits messages from the body to the brain.
While several genes in the male-only or female-only list were linked with psychiatric disorders or immune function, only one, called DCC, was found in both lists.
DCC encodes for a receptor that binds with a protein crucial for the development of the nervous system, especially the dopaminergic system. The dopaminergic system is the ‘reward centre’ but also has been linked to pain.

DCC is also linked to depression, and DCC mutations appear in those with congenital mirror movement disorder, which results in movements on one side of the body being replicated on the other side.

It’s not how DCC is linked to chronic pain, but the researchers believe their results support several theories “of strong nervous system and immune involvement in chronic pain in both sexes”, which will, they hope, result in the development of better treatments.

Should chronic pain be more closely linked to immune function in women, immune-targeting drugs may have very different side-effects than in men. Opioids negatively impact immune function, indicating that they could in fact worsen the situation for women suffering chronic pain. However, more research is needed to strengthen these findings and understand their impacts.

“All of these lines of evidence, together, suggest putative central and peripheral neuronal roles for some of these genes, many of which have not been historically well studied in the field of chronic pain,” the authors concluded.

Source: Science Alert

Journal information: Johnston KJA, Ward J, Ray PR, Adams MJ, McIntosh AM, Smith BH, et al. (2021) Sex-stratified genome-wide association study of multisite chronic pain in UK Biobank. PLoS Genet 17(3): e1009428. doi.org/10.1371/journal.pgen.1009428

A Public Archive for Opioid Lawsuit Information

In order to improve transparency about the opioid crisis,  the University of California San Francisco and Johns Hopkins University launched a digital public archive of documents from lawsuits against drug manufacturers.

The digital repository of publicly disclosed legal documents related to the crisis allows free, public access to anyone interested in the continuing litigation and uncovered evidence.

“All too often, the public never gets the benefit of seeing and learning from litigation that generally takes place behind closed doors,” said Caleb Alexander, MD, a professor of epidemiology and medicine at Johns Hopkins and the founding co-director of the Center for Drug Safety and Effectiveness, which will assist in maintaining the archive.

“Our focus is to be sure that the millions of pages of documents arising from opioid litigation ultimately see the light of day,” Alexander told MedPage Today. “We owe it to all those who have been impacted — especially patients and their loved ones — to see to it that these materials are placed in the public domain.”

The goal of the archive is to provide transparency into the methods used by drug companies to increase opioid sales, which led to the opioid epidemic in which, according to the CDC, over the past two decades, nearly 500 000 Americans died of overdoses involving an opioid. Additionally, the economic cost of the crisis in 2015-2018 was put at $2.5 trillion by the White House Council of Economic Advisers.

Most of the archive’s documents were released thanks to efforts by the Washington Post and the Charleston Gazette. Records include company emails, memos, presentations, sales reports, audit reports, budgets, Drug Enforcement Administration briefings, expert witness reports, and depositions of drug company executives.

The archive is located on a website called Drug Industry Archives, a UCSF project that houses documents illustrating how the pharmaceutical industry, academic institutions, continuing medical education organizers and regulatory agencies impact public health. (UCSF also maintains similar archives related to tobacco, food, chemicals, and fossil fuel industries.)

The  Opioid Industry Documents Archive presently holds over 3300 legal documents, much of it coming from litigation in Kentucky and Oklahoma, as well as documents from the Insys investigation, which sold an oral fentanyl spray called Subsys. This archive’s launch coincides with the university hosting over 250 000 documents produced during Insys’ bankruptcy proceedings that resulted from successful lawsuits and criminal prosecutions.

“We don’t really know what’s in these documents yet, but there is a wealth of information,” said Kate Tasker, an associate librarian at UCSF who helps manage the archive. “Our number one goal is to make this information accessible and useful.”

Alexander said the opioid crisis was “an epidemic of catastrophic public health proportions.” He said that placing legal documents in the public domain is a crucial step to ensure that lessons are learned from the crisis.

“The primary goal is to ensure that history never repeats itself,” Alexander said. “And we can’t learn from past mistakes without understanding what those mistakes have been.”

Source: MedPage Today

Both Genders Rate Pain of Female Patients as Lower

Woman clutching her belly in pain. Photo by Andrea Piacquadio from Pexels.

In a recent study, researchers found that a patient’s pain responses may be perceived differently by others based on their gender.

The study was published in The Journal of Pain, with the co-author being Elizabeth Losin, assistant professor of psychology and director of the Social and Cultural Neuroscience lab at the University of Miami. A previous study showed that men are seen as more stoic and women as more emotional in expression of pain.

In the first of two experiments in the study, 50 participants viewed videos of male and female patients complaining of shoulder pain as they performed a series of range of motion exercises using their injured and uninjured shoulders. These videos came from a database that contains videos of actual shoulder injury patients, each with a different level of pain, as well as the patients’ self-reported discomfort levels on shoulder movement.

According to Prof Losin, this study is more applicable to patients in a clinical setting.
“One of the advantages of using these videos of patients who are actually experiencing pain from an injury is that we have the patients’ ratings of their own pain,” she explained. “We had a ground truth to work with, which we can’t have if it’s a stimulus with an actor pretending to be in pain.”

The patients’ facial expressions were also analysed through the Facial Action Coding System (FACS)—a system for describing all visible facial movements. The researchers created an objective score of the intensity of the patients’ pain facial expressions derived from the FACS values, providing a second ground truth.

The study participants were asked to gauge the amount of pain they thought the patients in the videos experienced on a scale from zero, labeled as “absolutely no pain,” to 100, labeled as “worst pain possible.”

For the second experiment, the first experiment was replicated with 200 participants, who were asked to complete the Gender Role Expectation of Pain questionnaire, which measures gender-related stereotypes about pain sensitivity, the endurance of pain, and willingness to report pain.

The participants also reported the amount of medication and psychotherapy they would prescribe to each patient, and which of these they believed be a more effective treatment for that patient.

The researchers analysed the participants’ perceptions relative to the two ground truth pain measures, Prof Losin explained. That is because bias could be defined as different ratings for male and female patients despite the same level of responses.

Overall, the study found that female patients were perceived to be in less pain than the male patients who reported, and exhibited, the same intensity of pain. Additional analyses using participants’ responses to the questionnaire about gender-related pain stereotypes allowed researchers to conclude that these perceptions were partially explained by these stereotypes. 

“If the stereotype is to think women are more expressive than men, perhaps ‘overly’ expressive, then the tendency will be to discount women’s pain behaviors,” Prof Losin said. “The flip side of this stereotype is that men are perceived to be stoic, so when a man makes an intense pain facial expression, you think, ‘Oh my, he must be dying!’ The result of this gender stereotype about pain expression is that each unit of increased pain expression from a man is thought to represent a higher increase in his pain experience than that same increase in pain expression by a woman.”

Additionally, the researchers found that psychotherapy was also selected over medication for a higher proportion of female than male patients. The participants’ gender did not influence pain estimation, with both male and female participants perceiving women’s pain to be less intense.

Prof Losin said the study was motivated by literature showing that women received less treatment for pain and waited longer.

“There’s a pretty wide literature showing demographic differences in pain report, the prevalence of clinical pain conditions, and then also a demographic difference in pain treatments,” Losin pointed out. “These differences manifest as disparities because it seems that some people are getting undertreated for their pain based on their demographics.”

Moving forward, Prof Losin and her fellow researchers hope this study is a step in identifying and addressing gender disparities in health care.

Prof Losin said that even medically trained people are subject to such biases. “Critically, our results demonstrate that these gender biases are not necessarily accurate. Women are not necessarily more expressive than men, and thus their pain expression should not be discounted.”

Source: Medical Xpress

Journal information: Lanlan Zhang et al, Gender Biases in Estimation of Others’ Pain, The Journal of Pain (2021). DOI: 10.1016/j.jpain.2021.03.001

Cannabinoid Effectiveness in Pain Management Questioned

The effectiveness of cannabinoids as pain management has been brought into question by experts reviewing clinical evidence.

Researchers from the University of Bath’s Centre for Pain Research leading experts from around the world reviewed existing data into cannabinoids, including that on so-called ‘medicinal cannabis’ and ‘medicinal cannabis extracts’.

Their findings suggest that while preclinical data supports the hypothesis of cannabinoid analgesia, uncertainties especially in clinical evidence do not reach the certainty in efficacy and safety necessary for the IASP to endorse their general use for pain control.
 The studies and the statement from the IASP are limited to the use of cannabinoids to treat pain, and not for other conditions for which cannabinoids are used.

Dr Emma Fisher who led the review of the clinical evidence said: “Cannabis, cannabinoids, and cannabis-based medicines are becoming an increasingly popular alternative to manage pain. However, our review shows that there is limited evidence to support or refute their use for the management of any pain condition. The studies we found were poor quality (high risk of bias) and the evidence was of very low-certainty, meaning that we are very uncertain of the findings and more research is needed.”

Professor Christopher Eccleston, Director of the Centre for Pain Research / Department for Health, said: “Cannabis seems to attract strong opinions. If ever a field needed evidence and a rigorous scientific opinion it is this one. For many this will be an unpopular conclusion, but we need to face up to the fact that the evidence is simply lacking. Science is not about popularity but keeping people safe from false claims. The challenge in this field will be for governments to fund independent research, and to ensure balance and equipoise.

“Coming close on the heels of The Lancet Commission on children’s pain and the WHO guidelines on treating chronic pain, this further contribution also found no evidence to support the use of cannabis, cannabinoids, and cannabis-based medicines for children with chronic pain. We need to invest in real solutions to the very real problem of chronic pain in children.”

Source: Medical Xpress

Journal information: IASP Presidential Task Force on Cannabis and Cannabinoid Analgesia. Painjournals.lww.com/pain/pages/co … picalCollectionId=23

Dopamine Affects Pain Differently in Female and Male Mice

Researchers have found that dopamine affects the neurons of male and female mice in different ways, a discovery which could have great potential in pain management for women, who suffer pain disproportionately throughout their lives.

Dopamine, popularly known as the brain’s ‘pleasure chemical’, is implicated in many functions, including the reward pathways and also the pain-relieving pathways associated with heroin that the researchers were focussing on. Dopamine is also suggested to be involved in attention, suggesting a link between substance abuse, pain and attention.

“We focused on this neural pathway because our previous work and that of others show that specific neurons release dopamine to regulate pain responses,” explained Thomas Kash, PhD, the John R Andrews Distinguished Professor of Pharmacology, School of Medicine lab, University of North Carolina. “Unfortunately, that research was done only in male mice. So we decided to look at both male and female mice, and what we found was very surprising.”

Previous research from Dr Kash’s lab using male mice showed that dopaminergic neurons were key in how opiates dampen pain, likely through dopamine and glutamate release. The new experiments focussed on a neural pathway starting at the midbrain region called the periaqueductal grey, including part of the dorsal raphe.

This brain region is involved in behavioural adaptation, which is the way animals respond to their environment. The dopamine-producing neurons in this region form a neural pathway with a structure known as the bed nucleus of the stria terminalis (BNST). 

“We found that activating this pathway reduced pain sensitivity in male mice, but made female mice move more, especially in the presence of something capturing their attention,” said first author Waylin Yu, PhD, a former graduate student in the Kash lab and current postdoctoral researcher at UC San Francisco. “We think this is because of the different ways males and females respond to pain.”

This seems to indicate that dopamine helps male mice simply not feel as much pain, while female mice are able to focus their attention elsewhere while experiencing pain.

While further investigation is needed, the results appear to show that the activation of specific neural projections to the BNST reduces acute and persistent inflammatory pain. This adds to the evidence that dopamine signaling can enhance the blocking of pain stimuli, counteracting severe pain.

“We hope to investigate how this pathway can regulate more emotional behaviours associated with chronic pain, and then also look at the dynamics of the system, such as how this pathway works in real time during behaviour measurements,” Dr Kash said. “These neurons are also implicated in the actions of opioids such as morphine, so we plan to investigate that domain, as well.”

Source: News-Medical.Net