Clinical utility, safety, and efficacy of pregabalin in the treatment of fibromyalgia

Transcranial direct current stimulation is more effective than pregabalin in controlling nociceptive and anxiety-like behaviors in a rat fibromyalgia-like model

OBJECTIVES

Despite the fact that fibromyalgia, a widespread disease of the musculoskeletal system, has no specific treatment, patients have shown improvement after pharmacological intervention. Pregabalin has demonstrated efficacy; however, its adverse effects may reduce treatment adherence. In this context, neuromodulatory techniques such as transcranial direct current stimulation (tDCS) may be employed as a complementary pain-relieving method. Consequently, the purpose of this study was to evaluate the effect of pregabalin and tDCS treatments on the behavioral and biomarker parameters of rats submitted to a fibromyalgia-like model.

METHODS

Forty adult male Wistar rats were divided into two groups: control and reserpine. Five days after the end of the administration of reserpine (1 mg/kg/3 days) to induce a fibromyalgia-like model, rats were randomly assigned to receive either vehicle or pregabalin (30 mg/kg) along with sham or active- tDCS treatments. The evaluated behavioral parameters included mechanical allodynia by von Frey test and anxiety-like behaviors by elevated plus-maze test (time spent in opened and closed arms, number of entries in opened and closed arms, protected head-dipping, unprotected head-dipping [NPHD], grooming, rearing, fecal boluses). The biomarker analysis (brain-derived neurotrophic factor [BDNF] and tumor necrosis factor-α [TNF-α]) was performed in brainstem and cerebral cortex and in serum.

RESULTS

tDCS reversed the reduction in the mechanical nociceptive threshold and the decrease in the serum BDNF levels induced by the model of fibromyalgia; however, there was no effect of pregabalin in the mechanical threshold. There were no effects of pregabalin or tDCS found in TNF-α levels. The pain model induced an increase in grooming time and a decrease in NPHD and rearing; while tDCS reversed the increase in grooming, pregabalin reversed the decrease in NPHD.

CONCLUSIONS

tDCS was more effective than pregabalin in controlling nociception and anxiety-like behavior in a rat model-like fibromyalgia. Considering the translational aspect, our findings suggest that tDCS could be a potential non-pharmacological treatment for fibromyalgia.

A phase I study to evaluate the safety, tolerability, and pharmacokinetics of a novel, potent GABA analog HSK16149 in healthy Chinese subjects

Purpose: HSK16149 is a novel, potent gamma-aminobutyric acid (GABA) analog for the treatment of neuropathic pain. This study aimed to evaluate the safety, tolerability, and pharmacokinetics of HSK16149 after single and multiple doses in healthy Chinese subjects. Methods: The randomized, double-blind, placebo-controlled study comprised two parts: SAD (single ascending-dose study) and MAD (multiple ascending-dose study). A total of 122 healthy subjects were enrolled in this study. HSK16149 capsule or placebo was administered as the protocol required. The safety of the drug was evaluated through clinical examinations and adverse events. Blood and urine samples were collected at the designated time intervals for pharmacokinetic analysis. Results: Subjects were generally well tolerated after HSK16149 administration and the most common treatment-emergent adverse event (TEAEs) was dizziness, which was expected based on the mechanism of action of HSK16149. In SAD, AUC and Cmax were shown to have a dose-proportional relationship in the dose range of 5-120 mg. The t1/2 of HSK16149 is 3.7-6.4 h. In MAD, after a single and multiple administration of 15-80 mg, AUC and Cmax are proportional to the increased dose of HSK16149, and the accumulative ratios of AUC and Cmax at steady-state were 1.05-1.44 and 1.07-1.36, respectively, indicating that HSK16149 only accumulated slightly after repeated administration. Conclusion: HSK16149 was well tolerated in healthy Chinese subjects. Based on the safety and pharmacokinetic data, 80 mg twice daily (BID) was suggested as the highest target dose for further clinical development. Clinical Trial Registration: http://www.chinadrugtrials.org.cn, identifier CTR20182535 and CTR20191317.

The Relative Value of Anti-Obesity Medications Compared to Similar Therapies

Purpose

To demonstrate a need for improved health insurance coverage for anti-obesity medications (AOMs) by comparing clinical and economic benefits of obesity treatments to covered medications for selected therapeutic areas.

Methods

Using a grey literature search, we identified and prioritized therapeutic areas and treatment analogues for comparison to obesity. A targeted literature review identified clinical and economic outcomes research across the therapeutic area analogues. Associated comorbidities, clinical evidence, indirect costs (ie, absenteeism and productivity loss), and direct medical costs were evaluated to determine the relative value of treating obesity.

Results

Four therapeutic areas/treatment analogues were selected for comparison to obesity: smoking cessation (varenicline), daytime sleepiness (modafinil), migraines (erenumab), and fibromyalgia (pregabalin). Obesity was associated with 17 comorbidities, more than migraine (9), smoking (8), daytime sleepiness (5), and fibromyalgia (2). Economic burden was greatest for obesity, followed by smoking, with yearly indirect and direct medical costs totaling $676 and $345 billion, respectively. AOMs resulted in cost savings of $2586 in direct medical costs per patient per year (PPPY), greater than that for varenicline at $930 PPPY, modafinil at $1045 PPPY, and erenumab at $468 PPPY; pregabalin utilization increased costs by $924 PPPY. AOMs were covered by 10-16% of United States health insurance plans, compared to 45-59% for the four comparators.

Conclusion

Compared to four therapeutic analogues, obesity represented the highest economic burden and was associated with more comorbidities. AOMs provide greater cost savings compared to selected analogues. However, AOMs have limited formulary coverage. Improved coverage of AOMs may increase access to these treatments and may help address the clinical and economic burden associated with obesity and its comorbidities.

Pregabalin administration in patients with fibromyalgia: a Bayesian network meta-analysis

Several studies investigated the effectiveness and the safety of different doses of pregabalin in fibromyalgia. However, the optimal protocol remains controversial. A Bayesian network meta-analysis comparing 300, 450, and 600 mg/daily of pregabalin for fibromyalgia was conducted. The literature search was conducted in January 2022. All the double-blind randomised clinical trials comparing two or more dose protocols of pregabalin for fibromyalgia were accessed. Studies enrolling less than 50 patients were not eligible, nor were those with a length of follow-up shorter than eight weeks. The outcomes of interests were: Fibromyalgia Impact Questionnaire (FIQ), sleep quality, and adverse events. The network meta-analyses were performed using the routine for Bayesian hierarchical random-effects model analysis, with log odd ratio (LOR) and standardized mean difference (SMD) effect measure. Data from 4693 patients (mean age 48.5 years) were retrieved. 93.1% (4370 of 4693 patients) were women. The median follow-up was 14.8 weeks. Pregabalin 450 mg/daily resulted in greater reduction in Fibromyalgia Impact Questionnaire (SMD − 1.83). Pregabalin 600 demonstrated the greatest sleep quality (SMD 0.15). Pregabalin 300 mg/daily evidenced the lowest rate of adverse events (LOR 0.12). The dose of pregabalin must be customised according to patients’ characteristics and main symptoms.

Masticatory Myofascial Pain Syndrome: Implications for Endodontists

INTRODUCTION

Masticatory myofascial pain syndrome can present similarly to other dental conditions in odontogenetic structures. Endodontists should be familiar with the symptomology and pathophysiology of masticatory myofascial pain syndrome to avoid misdiagnosis, incorrect treatment, and medicolegal repercussions. The aim of this review was to provide a foundational summary for endodontists to identify and correctly manage masticatory myofascial pain syndrome.

METHODS

A narrative review of the literature was performed through a MEDLINE search and a hand search of the major myofascial pain textbooks.

RESULTS

Masticatory myofascial pain syndrome is a musculoligamentous syndrome that can present similarly to odontogenic pain or refer pain to the eyebrows, ears, temporomandibular joints, maxillary sinus, tongue, and hard palate. Currently, the most comprehensive pathophysiology theory describing masticatory myofascial pain syndrome is the expanded integrated hypothesis. The most widely accepted diagnostic guidelines for masticatory myofascial pain syndrome are the Diagnostic Criteria for Temporomandibular Disorders; however, their diagnostic capability is limited. There is no hierarchy of treatment methods because each patient requires a tailored and multidisciplinary management aimed at regaining the muscle's range of motion, deactivating the myofascial trigger points, and maintaining pain relief.

CONCLUSIONS

The pain patterns for masticatory myofascial pain syndrome are well-known; however, there is a lack of consensus on the most proper method of trigger point diagnosis or pain quantification. The diagnostic strategies for masticatory myofascial pain syndrome vary, and the diagnostic aids are not well developed.

Therapeutic Effects of Ba-Duan-Jin versus Pregabalin for Fibromyalgia Treatment: Protocol for a Randomized Controlled Trial

INTRODUCTION

Fibromyalgia is characterized by multi-focal pain and is associated with fatigue, unrefreshing sleep and psychological impairment. Pregabalin is one of the most frequently used agents in fibromyalgia treatment. However, it has failed to demonstrate benefit over placebo for reducing fatigue and psychological impairment, and may cause adverse effects (e.g. somnolence, dizziness). "Ba-Duan-Jin" (BDJ) is a common form of "Qigong" exercise for health promotion in China. Growing evidence suggests that BDJ may achieve satisfactory control of fibromyalgia-related symptoms in Chinese patients. Therefore, we wish to ascertain if BDJ could overcome the disadvantages of pregabalin.

METHODS

A single-blind randomized controlled trial has been designed which will recruit 104 patients with fibromyalgia (age 18-70 years) with a visual analog scale (VAS) pain score of ≥ 40 mm These patients will be randomly assigned to one of two groups: (1) BDJ group (to undertake guided BDJ exercise and take a placebo capsule) or (2) pregabalin group (to take a pregabalin capsule and receive wellness education and guided muscle-relaxation exercises). The primary endpoint will be changes in the VAS score for pain. The secondary endpoints will be changes in the score for the Revised Fibromyalgia Impact Questionnaire, Multidimensional Fatigue Inventory-20, Pittsburgh Sleep Quality Index, Beck II Depression Inventory, Perceived Stress Scale and Short Form-36 Health Survey Questionnaire. These parameters will be assessed at 0, 4, 8, 12 and 24 weeks of follow-up.

PLANNED OUTCOMES

Our results are expected to provide more clinical evidence for the beneficial effects of BDJ in treating fibromyalgia.

TRIAL REGISTRATION

NCT03797560.

Ingestion of a THC-Rich Cannabis Oil in People with Fibromyalgia: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Objective

To determine the benefit of a tetrahydrocannabinol (THC)-rich cannabis oil on symptoms and quality of life of fibromyalgia patients.

Methods

A double-blind, randomized, placebo-controlled clinical trial was conducted for eight weeks to determine the benefit of a THC-rich cannabis oil (24.44 mg/mL of THC and 0.51 mg/mL of cannabidiol [CBD]) on symptoms and quality of life of 17 women with fibromyalgia, residents of a neighborhood with a low socioeconomic profile and a high incidence of violence in the city of Florianopolis, Brazil. The initial dose was one drop (∼1.22 mg of THC and 0.02 mg of CBD) a day with subsequent increases according to symptoms. The Fibromyalgia Impact Questionnaire (FIQ) was applied at pre- and postintervention moments and in five visits over eight weeks.

Results

There were no significant differences on baseline FIQ score between groups. However, after the intervention, the cannabis group presented a significant decrease in FIQ score in comparison with the placebo group (P = 0.005) and in comparison with cannabis group baseline score. (P < 0.001). Analyzing isolated items on the FIQ, the cannabis group presented significant improvement on the “feel good,” “pain,” “do work,” and “fatigue” scores. The placebo group presented significant improvement on the “depression” score after intervention. There were no intolerable adverse effects.

Conclusions

Phytocannabinoids can be a low-cost and well-tolerated therapy to reduce symptoms and increase the quality of life of patients with fibromyalgia. Future studies are still needed to assess long-term benefits, and studies with different varieties of cannabinoids associated with a washout period must be done to enhance our knowledge of cannabis action in this health condition.

Fibromyalgia: Recent Advances in Diagnosis, Classification, Pharmacotherapy and Alternative Remedies

Fibromyalgia (FM) is a syndrome that does not present a well-defined underlying organic disease. FM is a condition which has been associated with diseases such as infections, diabetes, psychiatric or neurological disorders, rheumatic pathologies, and is a disorder that rather than diagnosis of exclusion requires positive diagnosis. A multidimensional approach is required for the management of FM, including pain management, pharmacological therapies, behavioral therapy, patient education, and exercise. The purpose of this review is to summarize the recent advances in classification criteria and diagnostic criteria for FM as well as to explore pharmacotherapy and the use of alternative therapies including the use of plant bioactive molecules.

Tolerability, pharmacokinetics, and pharmacodynamics of mirogabalin in healthy subjects: Results from phase 1 studies

Three phase 1 pharmacokinetic (PK)/pharmacodynamics (PD) studies were conducted in healthy men and women to further characterize the safety, tolerability, and PK/PD of mirogabalin administration with or without food and to guide the dose selection and regimen for phase 2 and 3 clinical development. The 3 studies included 2 randomized, double-blind, placebo-controlled, single- and multiple-ascending-dose studies, and 1 open-label, crossover study to evaluate the PK of mirogabalin administered under fasting and fed (high-fat meal) conditions. Forty-eight and 47 healthy volunteers completed the single- and multiple-dose studies, respectively. Thirty subjects were enrolled and completed the food effect study. Mirogabalin was well tolerated in the fed and fasted states. The most frequent treatment-emergent adverse events (TEAEs)-dizziness and somnolence-were expected based on mirogabalin's mechanism of action. Subjects receiving the highest mirogabalin doses (50 and 75 mg single dose) showed greater dizziness and sedation and higher rates of TEAEs than subjects receiving 3-30 mg. After oral administration, mirogabalin was rapidly absorbed (time to maximum concentration, ∼1 hour) and eliminated through urine unchanged (61%-72% urinary excretion). Exposure increased in a dose-proportional manner after single or multiple mirogabalin doses. No significant accumulation occurred with multiple doses over 14 days. After single doses of mirogabalin (15 mg), the bioavailability was considered equivalent in the fed and fasted states, indicating that mirogabalin can be taken without food restrictions. Based on these data, mirogabalin 15 mg twice daily was selected as the highest target dose for further clinical development.

Effects of pregabalin and duloxetine on neurotransmitters in the dorsal horn of the spinal cord in a rat model of fibromyalgia

Dysfunction of the monoamine systems in the nervous system is associated with the clinical symptoms of fibromyalgia. Reserpine-induced myalgia (RIM) rats are a putative model of fibromyalgia in which muscle pressure thresholds and monoamine content is reduced in the brain and spinal cord. We examined the effects of pregabalin and duloxetine, drugs approved for fibromyalgia treatment, on the levels of extracellular neurotransmitters in the dorsal horn of the spinal cord in RIM rats using microdialysis. Male SD rats were used for all experiments. To generate RIM rats, reserpine was injected at 1 mg/kg subcutaneously once daily for three consecutive days. The pressure threshold of the mid-gastrocnemius muscle was measured using a Randall-Selitto apparatus. Norepinephrine, dopamine, and serotonin were detected using high-performance liquid chromatography with electrochemical detection, and glutamate and γ-aminobutyric acid (GABA) were detected using liquid chromatography-mass spectrometry. The muscle pressure threshold in RIM rats was significantly lower than that in normal rats. While the levels of monoamines and glutamate were lower in the spinal cord of RIM rats than in normal rats, levels of GABA did not markedly differ. Duloxetine increased the levels of all three monoamines in normal and RIM rats in a dose-dependent manner. In contrast, pregabalin only increased norepinephrine levels in RIM rats. These results indicate that while both pregabalin and duloxetine ameliorate muscle pressure thresholds in RIM rats, their effects on the levels of extracellular neurotransmitters in the spinal cord differ considerably.

Pregbalin induced recurrent syncopal attacks with prolong QT interval

Long QT syndrome may lead to fatal dysrhythmia. Prolongation of QT interval due to pregabalin has been shown in rats and no data is available in humans. We report a 80-year-old female patient using pregabalin. She was presented to emergency room with syncope attacks. Her admission electrocardiography demonstrated prolonged QT interval. After excluding the possible causes of the long QT syndrome, we attributed prolonged QT interval to pregabalin therapy. After discontinuation of pregabalin QT interval returned to normal range and patient experienced no further syncope attacks. It is first time for documentation of prolonged QT due to pregabalin in humans.