Are psychedelics the answer to chronic pain: A review of current literature

AIMS

We aim to provide an evidence-based overview of the use of psychedelics in chronic pain, specifically LSD and psilocybin.

CONTENT

Chronic pain is a common and complex problem, with an unknown etiology. Psychedelics like lysergic acid diethylamide (LSD) and psilocybin, may play a role in the management of chronic pain. Through activation of the serotonin-2A (5-HT2A) receptor, several neurophysiological responses result in the disruption of functional connections in brain regions associated with chronic pain. Healthy reconnections can be made through neuroplastic effects, resulting in sustained pain relief. However, this process is not fully understood, and evidence of efficacy is limited and of low quality. In cancer and palliative related pain, the analgesic potential of psychedelics was established decades ago, and the current literature shows promising results on efficacy and safety in patients with cancer-related psychological distress. In other areas, patients suffering from severe headache disorders like migraine and cluster headache who have self-medicated with psychedelics report both acute and prophylactic efficacy of LSD and psilocybin. Randomized control trials are now being conducted to study the effects in cluster headache Furthermore, psychedelics have a generally favorable safety profile especially when compared to other analgesics like opioids. In addition, psychedelics do not have the addictive potential of opioids.

IMPLICATIONS

Given the current epidemic use of opioids, and that patients are in desperate need of an alternative treatment, it is important that further research is conducted on the efficacy of psychedelics in chronic pain conditions.

The effect of preferred music versus disliked music on pain thresholds in healthy volunteers. An observational study

Pain is a prevalent and debilitating healthcare problem. Since pharmacological treatments have numerous side-effects, additional treatment could be beneficial. Music has been shown to affect the pain perception and the pain threshold. The objective of this observational study was to evaluate the effect of preferred music as opposed to disliked music on pain (tolerance) thresholds and perceived pain intensity in healthy volunteers. Pain thresholds were measured via quantitative sensory testing. The volunteers were randomly assigned to either handheld pressure algometry to assess the pressure pain threshold to or electrical measurements to assess the electrical pain tolerance threshold while listening to preferred and disliked music. The pain thresholds were administered on the dorsal side of the forearm. The perceived pain intensity was assessed via a numerical rating scale, ranging from 0 (no pain) to 10 (worst pain imaginable). In total 415 volunteers were included in this study. The pressure pain threshold was assessed in 277 volunteers and in the electrical pain tolerance threshold test 138 volunteers were entered. In both groups, preferred music yielded higher pain thresholds than disliked music (P<0.001) and lower perceived pain intensity during the stimulus (P = 0.003). Moreover, the highest pain thresholds of both pressure pain and electrical pain tolerance thresholds were obtained when the preferred music was preceded by disliked music. Listening to preferred music when receiving noxious stimuli leads to higher pain thresholds and lower perceived pain scores in comparison with disliked music. Preferred music could be beneficial for patients with pain or undergoing painful procedures.

[PEricapsular Nerve Group (PENG) block after a hip fracture]

Annually an estimated amount of 17.500 patients are admitted at the hospital with a fractured hip in the Netherlands. This often fragile population experiences many unwanted side effects with the use of strong painkillers. Currently used locoregional anesthetic techniques do not fully block pain in most hip fractures. In 2018 a novel technique was published, based on the innervation of the anterior hip capsule: 'The PEricapsular Nerve Group (PENG) block'. Based on current evidence, the PENG block seems a promising pain reducing technique in acute pain in pericapsular hip fractures and surgery. Due to the possibility of chemical denervation of the hip capsule, current literature and our own data show that long-term pain reduction is possible as well, without motor loss. This can lead to an increase of quality of life, and reduction of morbidity and mortality in the most fragile patients, who are not eligible for surgery.

Chronic postsurgical pain after minimally invasive adrenalectomy: prevalence and impact on quality of life

BACKGROUND

Minimally invasive adrenalectomy is the standard of care for small adrenal tumours. Both the transperitoneal lateral approach and posterior retroperitoneal approach are widely used and have been proven to be safe and effective. However, the prevalence of chronic postsurgical pain has not been specifically investigated in previous studies. The primary goal of this study was to identify the prevalence of chronic postsurgical pain after minimally invasive adrenalectomy.

METHODS

A cross-sectional study was performed among all consecutive patients who had undergone minimally invasive adrenalectomy in a single university medical centre. The primary outcome was the prevalence of chronic postsurgical pain. Secondary outcomes were the prevalence of localized hypoesthesia, risk factors for the development of chronic postsurgical pain, and the Health-Related Quality of Life. Three questionnaires were used to measure the prevalence and severity of chronic postsurgical pain, hypoesthesia, and Health-Related Quality of Life. Logistic regression analysis was performed to determine risk factors for development of chronic postsurgical pain.

RESULTS

Six hundred two patients underwent minimally invasive adrenalectomy between January 2007 and September 2019, of whom 328 signed informed consent. The prevalence of chronic postsurgical pain was 14.9%. In the group of patients with chronic postsurgical pain, 33% reported hypoesthesia as well. Young age was a significant predictor for developing chronic postsurgical pain. The prevalence of localized hypoesthesia was 15.2%. In patients with chronic postsurgical pain, Health-Related Quality of Life was significantly lower, compared to patients without pain.

CONCLUSIONS

The prevalence of chronic postsurgical pain following minimally invasive adrenalectomy is considerable. Furthermore, the presence of chronic postsurgical pain was correlated with a significant and clinically relevant lower Health-Related Quality of Life. These findings should be included in the preoperative counselling of the patient. In the absence of evidence for effective treatment in established chronic pain, prevention should be the key strategy and topic of future research.

Qualitative Evaluation of the Influence of Acute Oxaliplatin-Induced Peripheral Neuropathy on Quality of Life and Activities of Daily Life

Introduction/Aims

Oxaliplatin often causes acute or chronic peripheral neuropathy in patients with an intestinal or pancreatic tumor, but in‐depth insights in its influence on quality of life (QoL) are lacking. We explored the influence of acute oxaliplatin‐induced peripheral neuropathy (OIPN) on daily QoL in these patients.

Methods

We performed semistructured interviews with a purposive sample of patients receiving oxaliplatin and possibly experiencing acute OIPN. Interviews were audio‐recorded, transcribed verbatim, and coded by two researchers. Data were analyzed by using the constant comparative method for content analysis with ATLAS.ti software.

Results

After nine patients, saturation took place. In total, 11 patients were interviewed. Four themes were extracted from the data: (1) adverse effects, (2) physical (un)well‐being, (3) emotional aspects, and (4) treatment aspects. All participants were suffering from acute OIPN to a certain extent, leading to restrictions in daily activities such as household chores, but also to a decrease in mobility and independency. Other adverse effects such as general malaise and gastrointestinal side effects also influenced the participants’ well‐being, as did the diagnosis and prognosis of their disease.

Conclusion

Acute OIPN, together with other side effects of chemotherapeutic treatment and the difficulties that come with the diagnosis of cancer and its prognosis, largely influences patients’ daily QoL. Managing expectations (by patient education) seems important.

Acute Cytokine Response During Breast Cancer Surgery: Potential Role of Dexamethasone and Lidocaine and Relationship with Postoperative Pain and Complications - Analysis of Three Pooled Pilot Randomized Controlled Trials

Purpose

An imbalance in perioperative cytokine response may cause acute pain and postoperative complications. Anesthetic drugs modulate this cytokine response, but their role in non-major breast cancer surgery is unclear. In an exploratory study, we investigated whether intravenous lidocaine and dexamethasone could modulate the cytokine response into an anti-inflammatory direction. We also evaluated interrelationships between cytokine levels, pain scores and postoperative complications. Our goal is to develop multimodal analgesia regimens optimizing outcome after breast cancer surgery.

Patients and Methods

Forty-eight patients undergoing a lumpectomy were randomly assigned to placebo or lidocaine (1.5 mg⋅kg⁻¹ followed by 2 mg⋅kg⁻¹⋅hour⁻¹) supplemented by dexamethasone zero, 4 or 8 mg, yielding six groups of eight patients. Interleukin (IL)-1β, IL-1Ra, IL-6, IL-10 levels and pain scores were measured at baseline and four hours postoperatively. We assessed postoperative complications occurring within 30 days. We noted persistent pain and infections as potential immune-related complications (PIRC). We used multiple regression to disentangle the effects of the individual study drugs (given by their partial regression coefficients (b)). Odds ratios (OR) estimated the link between pain scores and complications.

Results

Dexamethasone 8 mg increased IL-10 (b=12.70 (95% CI=8.06–17.34), P<0.001). Dexamethasone 4 mg and 8 mg decreased the ratio IL-6/IL-10 (b=−2.60 (−3.93 to −1.26), P<0.001 and b=−3.59 (−5.04 to −2.13), P<0.001, respectively). We could not show modulatory effects of lidocaine on cytokines. High pain scores were linked to the occurrence of PIRC’s (OR=2.028 (1.134–3.628), P=0.017). Cytokine levels were not related either to acute pain or PIRC.

Conclusion

Dexamethasone modulated the perioperative cytokine response into an anti-inflammatory direction. An overall lidocaine effect was not found. Patients with higher pain scores suffered from more 30-day PIRCs. Cytokine levels were not associated with pain or more postoperative complications, even not with PIRC. Larger studies in breast cancer surgery are needed to confirm these explorative results.

Simple surface EMG recording as a noninvasive screening method for the detection of acute oxaliplatin-induced neurotoxicity: a feasibility pilot study

OBJECTIVES

Oxaliplatin-induced neurotoxicity can be a dose-limiting side effect to effective chemotherapy. Acute hyperexcitability causes cold-evoked sensory and motor symptoms, which resemble neuromyotonia. An accessible and non-invasive technique for early detection could help select patients for potential treatments. We assessed the use of a simple surface electromyography (sEMG) in patients directly after oxaliplatin infusion.

METHODS

In patients with colorectal cancer, acute neurotoxicity was evaluated by means of a physical examination, a questionnaire, and sEMG directly after the second and fourth cycle of oxaliplatin. Questionnaires were also assessed 1 day after infusion.

RESULTS

14 patients were measured after the second cycle and 8 patients were also measured after the fourth cycle of oxaliplatin. All patients reported to a variable degree oxaliplatin induced neurotoxicity symptoms: sensitivity to touching cold or swallowing cold items were reported as most severe. Clinical signs of hyperexcitability were observed in 55% of the measurements. Spontaneous activity compatible with neuromyotonia was observed in 82% of the sEMG recordings.

CONCLUSIONS

Patient reported symptoms, physical examination and simple sEMG are complementary measurements to detect acute oxaliplatin induced neurotoxicity. After further validation, sEMG recording can be used as a simple objective screenings tool to detect nerve hyperexcitability directly after oxaliplatin administration.