Pregabalin Prescription for Neuropathic Pain and Fibromyalgia: A Descriptive Study Using Administrative Database in Japan

Analysis of Japanese nationwide health datasets: association between lifestyle habits and prevalence of neuropathic pain and fibromyalgia with reference to dementia-related diseases and Parkinson's disease

OBJECTIVES

Chronic pain is defined as pain that persists or recurs for more than 3 months. This study focuses on neuropathic pain (NP) and fibromyalgia (FM) which are chronic pain states, and aims to identify lifestyle habits associated with their prevalence. Other neurological disorders are also analyzed as references.

METHODS

Association between the variable referring to disease prevalence (number of claims for reimbursement of marker drugs) and the variable for lifestyle habits/health examination results (collected from insured individuals aged 40-74 years) was determined by analyzing Japanese nationwide datasets, which were collected in 2018 and aggregated by prefecture. Pregabalin, donepezil, and levodopa were used as marker drugs for the chronic pain states, dementia-related diseases (Alzheimer's disease and Lewy body dementia) and Parkinson's disease (PD), respectively. Pearson's correlation analysis and multiple linear regression analysis were conducted.

RESULTS

Variables showing correlation coefficient (|r|)>0.5 were put into the multiple linear regression. Exercise habits (ꞵ=-0.3182), smoking habits (0.3218), daily drinking (0.2683), and alanine aminotransferase>51 U/L (0.2309) were finally incorporated in the equation for pregabalin (R 2=0.7268). Walking speed (-0.4543) and daily drinking (0.5077) were incorporated in the equation for donepezil (R 2=0.5718).

CONCLUSIONS

The prevalence of chronic pain states is associated with lifestyle habits, just like the dementia-related diseases. Exercise in daily life is negatively associated with the prevalence of the chronic pain states, although excessive alcohol drinking, smoking, and high serum ALT are positively associated with it. The prevalence of PD seems less associated with lifestyle habits.

Real-world safety and efficacy of amenamevir in patients with herpes zoster in Japan: A postmarketing observational study (REWARD)

The helicase-primase inhibitor amenamevir (AMNV) was approved for herpes zoster in Japan in 2017. The authors conducted a 1-month postmarketing observational study to evaluate the real-world safety and efficacy (cutaneous improvement and pain resolution) of AMNV in patients with herpes zoster. Of the 3453 patients registered between March 2018 and December 2020, 3110 were included in the safety analyses. The mean age (±standard deviation) was 63.7 ± 17.5 years, with 57.9% of patients aged ≥65 years. Most patients had mild (53.3%) or moderate (41.0%) cutaneous lesions. Regarding pain, 43.9%, 25.6%, and 12.5% of patients had pain at the levels of 1-3, 4-6, and 7-10 on the numerical rating scale. In total, 30.0%, 27.2%, and 16.1% of patients were concomitantly treated with analgesics: acetaminophen, nonsteroidal anti-inflammatory drugs, and Ca2+ channel α 2δ ligands, respectively, and 10.6% were treated with topical antiherpetic drugs. Adverse drug reactions occurred in 0.77% of patients, including four serious adverse drug reactions in four patients (hyponatremia, thrombocytopenia, rash, and rhabdomyolysis). Regarding important potential risks, renal disorder, cardiovascular events, and decreased platelets were observed in one, one, and two patients, respectively. Concerning efficacy, the cutaneous improvement rate (significantly improved or improved) was 95.5%, with significantly higher improvement rates in patients treated with AMNV for 7 days and in patients with less severe cutaneous lesions or less pain. Factors affecting the time to pain resolution were the severity of cutaneous lesions and pain at the start of AMNV treatment and older age. This study demonstrated that the AMNV is safe and effective in patients with herpes zoster in a real-world clinical setting.

High-flow continuous hemodiafiltration successfully decreased blood pregabalin levels in a patient with severe pregabalin intoxication: a case report

Background

Severe pregabalin intoxication may cause serious symptoms, such as coma. Since pregabalin is a small molecule with no protein binding sites and has low volume of distribution, hemodialysis can be effective in eliminating pregabalin from the blood. However, in cases of emergency, it is not always possible to perform hemodialysis because of limited availability and time delay associated with using the plumbing equipment. Continuous hemodiafiltration (CHDF) can be performed without plumbing equipment; however, the knowledge on the effectiveness of CHDF in pregabalin elimination is insufficient.

Case presentation

A septuagenarian woman with normal renal function was found in a collapsed state with symptoms of coma and miosis. Empty medical bags of pregabalin (2350 mg), bepotastine besilate (600 mg), celecoxib (4600 mg), quetiapine fumarate (87.5 mg), clotiazepam (180 mg), and teprenone (50 mg) were found around her. During the patient's transfer to our hospital, her cognition worsened and she developed glossoptosis necessitating her emergent intubation upon arrival. We considered that the coma was mainly caused by pregabalin intoxication and were concerned about the consequent critical comorbidities. Thus, we performed CHDF in a high-flow setting in our intensive care unit for pregabalin elimination. After 8 h of CHDF, the patient regained consciousness, and after 6.5 h we extubated her. At a later date, we measured her serum pregabalin levels during the clinical course and estimated the blood pregabalin clearance levels depending on her metabolism as 76.8 mL/min and depending on CHDF itself as 65.1 mL/min. Based on these findings, we concluded that CHDF contributed to reducing blood pregabalin levels in this patient.

Conclusions

Our case revealed that pregabalin clearance using CHDF is similar to metabolic clearance in patients with normal renal function, indicating that CHDF decreases blood pregabalin levels and can be a potential treatment for severe pregabalin intoxication.

Off-label use of antidepressants, antipsychotics, and mood-stabilizers in psychiatry

Off-label drug prescribing in psychiatry is increasing. Many psychotropic drugs are approved for psychopathologic syndromes rather than based on international standard diagnostic classification systems which might facilitate the clinical decision for off-label prescriptions. The objective of this study was to analyze the prevalence and category of off-label use of psychotropic drugs. The study was conducted in 10 psychiatric hospitals in Germany over a period of 2 years. Prescription data of all patients were retrospectively analyzed after identification of antidepressants, antipsychotics, and mood-stabilizers, which were classified as off-label according to the German prescribing information and diagnostic classification according to ICD-10. In total, 53,909 patient cases (46% female) with a mean age of 46.8 (SD: 18) years were included in the study. 30.2% of the cases received at least one off-label prescription of a psychotropic drug during hospital stay. Off-label prevalence rates differed markedly between different diagnostic groups (ICD-10 F0/G3: 47%, F1: 33%, F2: 25%, F3: 21%, F4: 27%, F6: 46%, F7: 84%). The most often off-label prescribed drugs were quetiapine and mirtazapine for organic mental disorders (F0/G3), valproate and quetiapine in patients with disorders due to psychoactive substance use (F1), valproate in patients with psychotic disorders (F2), and risperidone and olanzapine in patients with affective disorders (F3). The prevalence rate of psychotropic off-label prescriptions is high if restricted to product description and ICD-10 diagnosis. Therefore, current psychiatric guidelines should drug-specifically issue this problem by defining psychiatric off-label indications based on a clear benefit-risk assessment.

Corydecumine G inhibits microglia activation via MAPK pathway in a rat model of neuropathic pain

BACKGROUND AND PURPOSE

Microglial activation plays an important role in the onset and progression of neuropathic pain by producing a variety of pro-inflammatory cytokines that interact with neurons to enhance neuronal hyperexcitability. Corydalis decumbens (Thunb.) pers., a traditional Chinese medicine has been used to treat mild cancer pain, dementia and to remit cerebral ischemia in clinics. Phenylphthalide isoquinolines are the major type of metabolites of C. decumbens and one of the derivatives, Corydecumine G (Cor G) has been shown to inhibit neuronal excitability. The present study aims to investigate the analgesic efficacy of Cor G in neuropathic pain rat model, the effects of Cor G on microglia activation and the possible mechanisms.

EXPERIMENTAL APPROACH

Neuropathic pain was modeled using chronic constriction sciatic nerve injury (CCI) in rats. Western blot, immunofluorescence, and qRT-PCR were used to evaluate the levels of protein and mRNA.

KEY RESULTS

Intraperitoneal administration of Cor G concentration-dependently ameliorates mechanical and thermo allodynia, suppresses CCI-induced p38/ERK phosphorylation and spinal cord microglia activation, and attenuates the expression levels of NO, inos, Tnf-α, Pge₂ in dorsal horn of L4-L6 spinal cord on the ligation side in CCI rats. Pretreatment with 30 μM Cor G decreased LPS-induced BV2 microglia activation, which occurred via the inos, Tnf-α, Il-1β, Il-6 and phospho-p38/ERK pathways.

CONCLUSIONS AND IMPLICATIONS

Taken together, we suggest that Cor G, the specific phthalide isoquinoline from traditional Chinese medicine Corydalis Decumbentis Rhizoma, may be promising for treatment of neuropathic pain.

Clinical epidemiology and pharmacoepidemiology studies with real-world databases

Hospital-based registry data, including patients' information collected by academic societies or government based research groups, were previously used for clinical research in Japan. Now, real-world data routinely obtained in healthcare settings are being used in clinical epidemiology and pharmacoepidemiology. Real-world data include a database of claims originating from health insurance associations for reimbursement of medical fees, diagnosis procedure combinations databases for acute inpatient care in hospitals, a drug prescription database, and electronic medical records, including patients' medical information obtained by doctors, derived from electronic records of hospitals. In the past ten years, much evidence of clinical epidemiology and pharmacoepidemiology studies using real-world data has been accumulated. The purpose of this review was to introduce clinical epidemiology and pharmacoepidemiology approaches and studies using real-world data in Japan.

A large-scale database study for the prescription status of a new voltage-gated Ca2+ channel α2δ ligand, mirogabalin, in Japan

BACKGROUND

A new voltage-gated Ca²⁺ channel α₂δ ligand, mirogabalin, was first approved for treating peripheral neuropathic pain in Japan in 2019. This is the first report on the prescription status of mirogabalin using a large-scale prescription database.

RESEARCH DESIGN AND METHODS

The authors analyzed the prescription data of 12,924 patients prescribed mirogabalin between 1 June and 31 August 2020. The endpoints were the number of patients prescribed, prescription days, prescription doses, dose changes, co-prescription patterns, medication possession ratio (MPR), and treatment discontinuation rates (TDRs).

RESULTS

Mirogabalin was newly prescribed to 7,914 patients in the 3-month study period. Most patients were prescribed mirogabalin at about 10 mg/day during the study period, and 30.9% of patients were prescribed ≥ 20 mg/day on Day 90 after the first prescription. The most frequently prescribed concomitant drug was celecoxib. The MPR (80 to 110%) was 86.2%, indicating good treatment adherence. The cumulative TDRs during ≤ 7 Days, Days 31-60, and 61-90 were 14.0%, 70.0%, and 77.9%, respectively.

CONCLUSIONS

Mirogabalin was prescribed to a considerable number of patients. These results may be useful for optimizing mirogabalin use for patients with peripheral neuropathic pain in daily clinical practice.

CLINICAL TRIAL REGISTRATION NUMBER

UMIN000042592.

Pregabalin for neuropathic pain in primary care settings: recommendations for dosing and titration

Pregabalin is one of the first-line treatments approved for the management of neuropathic pain (NeP). While many patients benefit from treatment with pregabalin, they are often treated with suboptimal doses, possibly due to unfamiliarity around prescribing the drug and/or side effects that can occur with up-titration. This narrative review discusses key aspects of initiating, titrating, and managing patients prescribed pregabalin therapy, and addresses concerns around driving and the potential for abuse, as well as when to seek specialist opinion. To ensure that patients derive maximum therapeutic benefit from the drug, we suggest a 'low and slow' dosing approach to limit common side effects and optimize tolerability alongside patients' expectations. When requiring titration to higher doses, we recommend initiating 'asymmetric dosing,' with the larger dose in the evening. Fully engaging patients in order for them to understand the expected timeline for efficacy and side effects (including their resolution), can also help determine the optimal titration tempo for each individual patient. The 'low and slow' approach also recognizes that patients with NeP are heterogeneous in terms of their optimal therapeutic dose of pregabalin. Hence, it is recommended that general practitioners closely monitor patients and up-titrate according to pain relief and side effects to limit suboptimal dosing or premature discontinuation.

Influence of single nucleotide polymorphism of LAT1 on therapeutic response to gabapentinoids in Pakistani patients with neuropathic pain

Gabapentinoids are substrate of L-type amino acid transporter 1 (LAT1) for distribution across the blood-brain barrier. The present study aimed to evaluate the effect of LAT1 rs4240803 genetic polymorphism on the clinical efficacy and tolerability of gabapentinoids in Pakistani patients with neuropathic pain. Three-hundred and ninety-two patients were recruited, genotyped for SNP rs4240803, and followed up for eight weeks to evaluate the clinical response to gabapentinoids in terms of pain relief, inadequate response, and the emergence of adverse events. LAT1 rs4240803 GG, GA, and AA genotype frequency were 33.42%, 47.96% and 18.62%, respectively. Out of 392 patients, 323 responded to the treatment and 17.6% discontinued either due to insufficient response or intolerable adverse events (AEs). GA genotype was more frequent in non-responder group (P ˂ 0.001). Maximum pain responders (≥50%) in combination with the lowest incidence of AEs were observed in the GG group, whereas partial responders belonged to GA genotype and with the highest frequency of somnolence (83.6%) and dizziness (69.9%). Overall, 72.5% patients with GA genotype experienced AEs (P ˂ 0.001). In conclusion, clinical outcomes of gabapentinoids are influenced by LAT1 rs4240803 polymorphism and population pharmacogenetics should be considered to evaluate the maximum potential of gabapentinoids in the management of neuropathic pain.

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.

A simple mechanistic terminology of psychoactive drugs: a proposal

Antidepressants, antiepileptics, mood stabilizers, and antipsychotics are extremely broadly used psychoactive drugs. These drug terms are universally used in the literature. However, the indications of these drugs have broadened substantially and overlap. The mismatch between drug classification and clinical uses causes a lot of confusion in communication and renders literature searches increasingly difficult. Therefore, we propose to drop the above terms altogether and replace them by simple mechanistic terms. Antidepressants are re-named as norepinephrine/serotonin (NE/5-HT) enhancers, antiepileptics comprising drugs with different mechanisms become neuronal inhibitors with pleiotropic effects (NIPEs), and antipsychotics become antagonists at multiple G protein-coupled receptors (mGPCR antagonists). Alkali metal ions, comprising lithium, are integrated into NIPEs. The terms "typical/first-generation/conventional" and "atypical/second-generation/non-conventional" antipsychotics should be dropped, because the original criterion for distinction, i.e., the presence and absence of extrapyramidal motor effects, respectively, is not valid anymore. The suggested changes in drug nomenclature have already been implemented into a recent textbook (Seifert R, Basic Knowledge of Pharmacology). The revised nomenclature ensures consistency with other fields of pharmacology and assignment of drug classes to indications without causing confusion. The authors acknowledge that the change in drug nomenclature is a cultural process that will take time and openly discuss the problems associated with the proposal. Ultimately, international learned societies will have to agree on a new nomenclature.

Spatiotemporal modelling of pregabalin prescribing in England with effect of deprivation

OBJECTIVE

This paper aims to understand spatial and temporal trends in pregabalin prescribing and the relationship with deprivation across England at both general practice and clinical commissioning group (CCG) levels.

DESIGN

A set of 207 independent generalised additive models are employed to model the spatiotemporal trend of pregabalin prescribed and dispensed per 1000 population, adjusting for deprivation. The response variable is pregabalin prescribed in milligrams, with weighted Index of Multiple Deprivation (IMD), geographical location and time as predictors. The set of active prescribing facilities grouped within CCG is the unit of analysis.

SETTING

National Health Service open prescribing data; all general practices in England, UK between January 2015 and June 2017.

POPULATION

All patients registered to general practices in England, UK.

RESULTS

Adjusting for deprivation, a North-South divide is shown in terms of prescribing trends, with the North of England showing increasing prescribing rates during the study period on average, while in the South of England rates are on average decreasing. Approximately 60% of general practices showed increasing prescribing rate, with the highest being 4.03 (1.75 for the most decreasing). There were no apparent spatial patterns in baseline prescription rates at the CCG level. Weighted IMD score proved to be statistically significant in 138 of 207 CCGs. Two-thirds of CCGs showed more pregabalin prescribed in areas of greater deprivation. Whether the prescribing rate is high due to high baseline prescription rate or increasing rates needs to be specifically looked at.

CONCLUSIONS

The spatial temporal modelling demonstrated that the North of England has a significantly higher chance to see increase in pregablin prescriptions compared with the South, adjusted for weighted IMD. Weighted IMD has shown positive impact on pregabalin prescriptions for 138 CCGs.

Clinical efficacy and tolerability of Gabapentinoids with current prescription patterns in patients with Neuropathic pain

Objective:

To investigate the current dosing regimens of gabapentinoids in Pakistani patients with neuropathic pain and to compare their clinical efficacy and tolerability in terms of pain relief and adverse effects using difference in pain score as a treatment outcome.

Methods:

This observational, prospective study was conducted in 320 patients with neuropathic pain from August 2016 to March 2018 at Basic Medical Sciences Institute (BMSI), Karachi in collaboration with Shifa International Hospital and Benazir Bhutto Hospital, Islamabad. Demographic data, treatment-related adverse effects and pain intensity was documented at recruitment and follow up visits at two, four and eight weeks. Discontinuation due to adverse effects and lack of efficacy were also recorded. Data was entered and analyzed using SPSS version 22.

Results:

Mean age of patients was 52.57±12.47 and the most common ethnicity were Punjabi speaking population (66%). Diabetic neuropathy (51%) was the most common etiology followed by radicular pain (25%). Mean dosages of pregabalin and gabapentin were 114mg and 470mg respectively. Mean pain score was significantly reduced by gabapentinoids (<0.001). Dizziness, drowsiness and somnolence were frequent adverse effects. Common dosages for pregabalin and gabapentin were 75 mg/day and 300 mg/day respectively.

Conclusion:

Current dosing regimens of gabapentinoids in Pakistani patients with neuropathic pain were found to be efficacious at low dosages in comparison to international recommended dosages. Gabapentin and pregabalin were both similar in terms of reducing pain score but onset of pain relief was relatively faster with pregabalin. Dizziness, drowsiness and somnolence were frequently reported with both gabapentinoids; however, visual blurring, ataxia and weight gain were observed only with the use of pregabalin. Adverse effects are frequently observed with gabapentinoids which necessitates reverting back to low dosages or switching to other drugs for pain relief.

Gabapentinoids for treatment of neuropathic pain: a medicines usage evaluation at the Groote Schuur Hospital Chronic Pain Management Clinic

Background: Neuropathic pain (NP), defined as pain caused by a lesion or disease of the somatosensory system, affects 6.9–10% of people worldwide. Pregabalin is currently recommended as a first line drug for NP in South Africa. Methods: A cross-sectional, retrospective, descriptive medicines usage evaluation (MUE) of pregabalin at Groote Schuur Hospital (GSH) Chronic Pain Management Clinic for the year 2017 was conducted. A MUE using a standardised data collection form was performed on 100 randomly selected patient folders. Data was summarised using descriptive statistics. Results: The majority of cases were women (76) with a mean age of 55.9 years (SD12.49). A diagnosis of NP was recorded in 58 folders and a “possible” diagnosis recorded in 7 folders. In 79 cases there was no mention of a tool/method used to diagnose NP. The most common condition diagnosed was chronic postsurgical pain with a neuropathic component (n = 16), followed by NP (n = 15). The most common initiating and current dose of pregabalin was 75 mg twice daily. In 56 patients, pregabalin was prescribed in conjunction with a tricyclic antidepressant (TCA) or selective noradrenaline reuptake inhibitor (SNRI). Patient education was documented as having taken place in 76 of cases. Conclusions: Based on this MUE we recommend the use of screening tools for the diagnosis of neuropathic pain, and a focus on the initiating dose of pregabalin. The use of a standardised assessment document and the interdisciplinary team input at this clinic appears to optimise prescribing of pregabalin in line with practice guidelines.