Safety and Efficacy of Melatonin in Chronic Tension-Type Headache: A Post-Marketing Real-World Surveillance Program

Neuronutritional Approach to Fibromyalgia Management: A Narrative Review

Fibromyalgia (FM) is a complex and common syndrome characterized by chronic widespread pain, fatigue, sleep disturbances, and various functional symptoms without clear structural or pathological causes. Affecting approximately 1-5% of the global population, with a higher prevalence in women, FM significantly impacts patients' quality of life, often leading to considerable healthcare costs and loss of productivity. Despite its prevalence, the etiology of FM remains elusive, with genetic, environmental, and psychological factors, including nutrition, being implicated. Currently, no universally accepted treatment guidelines exist, and management strategies are often symptomatic. This narrative review explores the potential of a neuronutritional approach to FM management. It synthesizes existing research on the relationship between FM and nutrition, suggesting that dietary interventions could be a promising complementary treatment strategy. Various nutritional interventions, including vitamin D, magnesium, iron, and probiotics supplementation, have shown potential in reducing FM symptoms, such as chronic pain, anxiety, depression, cognitive dysfunction, sleep disturbances, and gastrointestinal issues. Additionally, weight loss has been associated with reduced inflammation and improved quality of life in FM patients. The review highlights the anti-inflammatory benefits of plant-based diets and the low-FODMAPs diet, which have shown promise in managing FM symptoms and related gastrointestinal disorders. Supplements such as vitamin D, magnesium, vitamin B12, coenzyme Q10, probiotics, omega-3 fatty acids, melatonin, S-adenosylmethionine, and acetyl-L-carnitine are discussed for their potential benefits in FM management through various mechanisms, including anti-inflammatory effects, modulation of neurotransmitters, and improvement of mitochondrial function. In conclusion, this review underscores the importance of considering neuronutrition as a holistic approach to FM treatment, advocating for further research and clinical trials to establish comprehensive dietary guidelines and to optimize management strategies for FM patients.

Revealing Melatonin's Mysteries: Receptors, Signaling Pathways, and Therapeutics Applications

Melatonin (5-methoxy-acetyl tryptamine) is a sleep-inducing hormone, and the pineal gland produces it in response to the circadian clock of darkness. In the body, MT1 and MT2 receptors are mostly found, having an orthosteric pocket and ligand binding determinants. Melatonin acts by binding on melatonin receptors, intracellular proteins, and orphan nuclear receptors. It inhibits adenyl cyclase and activates phospholipase C, resulting in gene expression and an intracellular alteration environment. Melatonin signaling pathways are also associated with other intracellular signaling pathways, i. e., cAMP/PKA and MAPK/ERK pathways. Relative expression of different proteins depends on the coupling profile of G protein, accounting pharmacology of the melatonin receptor bias system, and mediates action in a Gi-dependent manner. It shows antioxidant, antitumor, antiproliferative, and neuroprotective activity. Different types of melatonin agonists have been synthesized for the treatment of sleeping disorders. Researchers have developed therapeutics that target melatonin signaling, which could benefit a wide range of medical conditions. This review focuses on melatonin receptors, pharmacology, and signaling cascades; it aims to provide basic mechanical aspects of the receptor's pharmacology, melatonin's functions in cancer and neurodegenerative diseases, and any treatments and drugs designed for these diseases. This will allow a basic comparison between the receptors in question, highlighting any parallels and differences that may exist and providing fundamental knowledge about these receptors to future researchers.

The Effect of Melatonin on Reducing the Frequency and Severity of Migraine Attacks: A Double-Blind, Randomized Clinical Trial

Background

There is no definite recommendation for melatonin supplementation in episodic migraine. This study aimed to evaluate the effect of melatonin on reducing the frequency and severity of migraine attacks.

Methods

This randomized, double-blind clinical trial was conducted at Golestan Hospital of Ahvaz, Iran, in 2021. A total of 60 patients with episodic migraine were randomly assigned into 2 groups of receiving 3 mg melatonin (intervention group; n=30) or the same dose of placebo (control group; n=30) along with baseline therapy (propranolol 20 mg, BID) for two months. The attack frequency, attack duration, attack severity (based on VAS), the number of analgesic intakes, drug complications, Migraine Disability Assessment score (MIDAS), and Pittsburgh sleep quality index (PSQI) were evaluated at baseline and in the first, second, third, and fourth months of follow-up. The independent t test, chi-square, and analysis of variance (ANOVA) with repeated measures were used to compare variables between the two groups.

Results

In both groups, the frequency, duration, and severity of attacks, taking analgesics, MIDAS, and PSQI scores during follow-up decreased significantly (P<0.001). After treatment, the mean frequency (P=0.032) and duration of attacks (P=0.001), taking analgesic (P<0.001), and MIDAS (P<0.001) and PSQI scores (P<0.001) in the melatonin group were lower than placebo. Only the attack severity was not significantly different between the two groups (P=0.126). Side effects were observed in two patients (6.7%) in the melatonin group and one patient (3.3%) in the placebo group (P>0.999).

Conclusion

Our study shows that melatonin was more efficacious than the placebo in the reduction of frequency and duration of migraine attacks. It was equally safe as the placebo and might be effective in the preventive treatment of episodic migraine in adults.Trial Registration Number: IRCT20190107042264N5.

Circadian pain patterns in human pain conditions - A systematic review

BACKGROUND

Chronobiology is the science of how physiological processes in the body follow a pattern of time. Pain has been shown to follow a circadian rhythm, with different types of pain having variable expression along this rhythm.

OBJECTIVE

This article reviews the nature of diurnal variations in pain along with a discussion of the mechanisms of circadian rhythm of pain.

EVIDENCE REVIEW

We conducted a literature search on the PubMed and Google Scholar electronic databases, through April 2022. Publications were screened for English language, full-text availability, and human subjects. Randomized controlled trials and observational trials were included. Data were extracted from studies on patients with acute or chronic pain phenotypes, which provide pain severity data and corresponding diurnal time points.

FINDINGS

The literature search led to the inclusion of 39 studies. A circadian pattern of pain was found to be present in nociceptive, neuropathic, central, and mixed pain states. Postoperative pain, fibromyalgia, trigeminal neuralgia, and migraines were associated with higher pain scores in the morning. Temporomandibular joint pain, neuropathic pain, labor pain, biliary colic, and cluster headaches increased throughout the day to reach a peak in the evening or night. Arthritis and cancer pain were not associated with any circadian rhythmicity. Furthermore, the circadian rhythm of pain was not found to be altered in patients on analgesics.

CONCLUSION

The results of this review suggest that an understanding of diurnal variation may help improve therapeutic strategies in pain management, for instance through analgesic titration.

Is Melatonin the "Next Vitamin D"?: A Review of Emerging Science, Clinical Uses, Safety, and Dietary Supplements

Melatonin has become a popular dietary supplement, most known as a chronobiotic, and for establishing healthy sleep. Research over the last decade into cancer, Alzheimer's disease, multiple sclerosis, fertility, PCOS, and many other conditions, combined with the COVID-19 pandemic, has led to greater awareness of melatonin because of its ability to act as a potent antioxidant, immune-active agent, and mitochondrial regulator. There are distinct similarities between melatonin and vitamin D in the depth and breadth of their impact on health. Both act as hormones, affect multiple systems through their immune-modulating, anti-inflammatory functions, are found in the skin, and are responsive to sunlight and darkness. In fact, there may be similarities between the widespread concern about vitamin D deficiency as a "sunlight deficiency" and reduced melatonin secretion as a result of "darkness deficiency" from overexposure to artificial blue light. The trend toward greater use of melatonin supplements has resulted in concern about its safety, especially higher doses, long-term use, and application in certain populations (e.g., children). This review aims to evaluate the recent data on melatonin's mechanisms, its clinical uses beyond sleep, safety concerns, and a thorough summary of therapeutic considerations concerning dietary supplementation, including the different formats available (animal, synthetic, and phytomelatonin), dosing, timing, contraindications, and nutrient combinations.

Melatonin Moderates the Triangle of Chronic Pain, Sleep Architecture and Immunometabolic Traffic

Preclinical as well as human studies indicate that melatonin is essential for a physiological sleep state, promotes analgesia and is involved in immunometabolic signaling by regulating neuroinflammatory pathways. Experimental and clinical neuromodulation studies for chronic pain treatment suggest that neurostimulation therapies such as spinal cord stimulation, vagus nerve stimulation and dorsal root ganglion stimulation have an impact on circulating inflammatory mediators in blood, cerebrospinal fluid and saliva. Herein, we provide an overview of current literature relevant for the shared pathways of sleep, pain and immunometabolism and elaborate the impact of melatonin on the crossroad of sleep, chronic pain and immunometabolism. Furthermore, we discuss the potential of melatonin as an adjunct to neurostimulation therapies. In this narrative review, we addressed these questions using the following search terms: melatonin, sleep, immunometabolism, obesity, chronic pain, neuromodulation, neurostimulation, neuroinflammation, molecular inflammatory phenotyping. So far, the majority of the published literature is derived from experimental studies and studies specifically assessing these relationships in context to neurostimulation are sparse. Thus, the adjunct potential of melatonin in clinical neurostimulation has not been evaluated under the umbrella of randomized-controlled trials and deserves increased attention as melatonin interacts and shares pathways relevant for noninvasive and invasive neurostimulation therapies.

Melatonin Abates TMJOA Chronic Pain by MT2R in Trigeminal Ganglion Neurons

Temporomandibular joint osteoarthritis (TMJOA) is one of the most common diseases causing chronic pain in the oral and maxillofacial region. So far, there are few ways to relieve the pain of TMJOA. Melatonin (MT) has a good analgesic effect in many diseases, including fibromyalgia, neuropathic pain, chronic headache, and burn pain, with very low acute toxicity and side effects. This study was to investigate the role and mechanism of MT in TMJOA chronic pain. In rats TMJOA chronic pain occurred at day 14 after an intra-temporomandibular joint injection of monosodium iodoacetate, which we previously reported. The enzyme-linked immunosorbent assay results showed that MT levels were higher in the synovial fluid from patients and rats with TMJOA as compared with those from control. Fluorescent retrograde tracing (Dil) identified that upregulation of MT type 2 receptor (MT₂R) in trigeminal ganglion (TG) neurons innervating rat temporomandibular joints was accompanied by TMJOA chronic pain. Nociceptive behavior as assessed by von Frey and the Rat Grimace Scale demonstrated that exogenous administration of MT relieved chronic pain in TMJOA rats, whereas blocking MT₂R with 4P-PDOT reversed the analgesic effect of MT. Immunofluorescence analysis also confirmed that MT inhibited CGRP and IB4 expression of TG neurons, and this inhibition was reversed by administering the MT₂R antagonist in TMJOA rats. By using Fluo-3 AM-based calcium imaging in vitro, MT elicited calcium transients in Dil⁺ TG neurons, which were significantly abolished by 4P-PDOT. Collectively, this study suggested that MT relieves the TMJOA chronic pain of rats through downregulation of sensitized CGRP⁺ and IB4⁺ neurons in TG via MT₂R. This will be helpful for health care professionals utilizing MT as an option against TMJOA chronic pain.

Endogenous melatonin levels and therapeutic use of exogenous melatonin in tension type headache: A systematic review

BACKGROUND-PURPOSE

A bidirectional relationship appears to connect tension-type headache (TTH) and circadian dysregulation. The present systematic review examined the published evidence for melatonin (MT) supplementation in the prophylaxis of TTH. Initially, we reviewed case-control studies investigating nocturnal MT or 6-sulphatoxymelatonin (aMT6s, a urine-discarded metabolite) in TTH individuals and healthy controls (HC). Secondly, we reviewed studies appraising the use of MT in the prevention of TTH.

METHODS

The search strategy involved MEDLINE EMBASE, CENTRAL, PsycINFO, trial registries, Google Scholar and OpenGrey. Case-control studies were appraised according to the Newcastle-Ottawa-Scale, whereas randomised controlled trials were assessed based on the risk-of-bias Cochrane tool. Infrequent, as well as frequent, episodic, and chronic TTH patients were evaluated separately in children and adults.

RESULTS

Our search strategy yielded two case-control studies. One (high-quality) did not reveal any difference in morning salivary MT concentration between children with frequent episodic TTH and HC. The second (moderate-quality) was indicative of a disturbed nocturnal secretion pattern in adults with chronic TTH. For the second part, five uncontrolled studies were retrieved. In total, 94 adults with chronic TTH were assessed and results were suggestive of a beneficial effect of MT on headache frequency, intensity, induced disability, and induced analgesic consumption. However, the uncontrolled-unblinded designs may have induced an important placebo effect. Non-adult populations and frequent TTH were substantially understudied.

CONCLUSIONS

There are not enough studies to designate the role of MT in the prevention of TTH. Given the disease's background, additional relevant research is warranted for chronic TTH.

Use of Nutraceutical Ingredient Combinations in the Management of Tension-Type Headaches with or without Sleep Disorders

Headache is the most common pain complaint in the pediatric population, with tension type headache (TTH) having a prevalence of 10–15% in children. Up to 70% of pediatric patients with chronic headache also experience sleep disruption, with a likely bidirectional relationship between headache and poor sleep. Treatment options include specific pharmacological approaches as well as non-pharmacological alternatives; nutraceuticals have the advantage of a relative lack of side effects. Exogenous melatonin has been shown to be useful and safe in improving sleep-wake cycles and quality of sleep in children, helping to regulate the circadian rhythm, with a secondary positive impact on headache. Supplementation with other nutraceutical ingredients, such as tryptophan, magnesium, and B vitamins, can have significant additional effects in children with primary headache, with or without sleep disorders. Tryptophan may reduce night awakenings and improve the efficiency of sleep. Primary headache has been related to low amounts of magnesium in serum, and integration with magnesium appears to be effective in reducing headache attacks without adverse effects. There are different observational reports and uncontrolled studies suggesting a possible synergistic effect for these nutraceuticals, but there is now a need for high-quality randomized controlled trials in order to confirm these positive preliminary findings.