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F1000Research 2015To determine the exact role of sodium channel proteins in migration, invasion and metastasis and understand the possible anti-invasion and anti-metastatic activity of... (Review)
Review
OBJECTIVE
To determine the exact role of sodium channel proteins in migration, invasion and metastasis and understand the possible anti-invasion and anti-metastatic activity of repurposed drugs with voltage gated sodium channel blocking properties.
MATERIAL AND METHODS
A review of the published medical literature was performed searching for pharmaceuticals used in daily practice, with inhibitory activity on voltage gated sodium channels. For every drug found, the literature was reviewed in order to define if it may act against cancer cells as an anti-invasion and anti-metastatic agent and if it was tested with this purpose in the experimental and clinical settings.
RESULTS
The following pharmaceuticals that fulfill the above mentioned effects, were found: phenytoin, carbamazepine, valproate, lamotrigine, ranolazine, resveratrol, ropivacaine, lidocaine, mexiletine, flunarizine, and riluzole. Each of them are independently described and analyzed.
CONCLUSIONS
The above mentioned pharmaceuticals have shown anti-metastatic and anti-invasion activity and many of them deserve to be tested in well-planned clinical trials as adjunct therapies for solid tumors and as anti-metastatic agents. Antiepileptic drugs like phenytoin, carbamazepine and valproate and the vasodilator flunarizine emerged as particularly useful for anti-metastatic purposes.
PubMed: 27408684
DOI: 10.12688/f1000research.6789.1 -
Value in Health : the Journal of the... Jul 2021Mexiletine is a long-known drug used for the treatment of arrhythmias and repurposed in the 1980s for patients with nondystrophic myotonia (NDM). Recently, the price of...
OBJECTIVES
Mexiletine is a long-known drug used for the treatment of arrhythmias and repurposed in the 1980s for patients with nondystrophic myotonia (NDM). Recently, the price of mexiletine in Europe increased significantly after registration as an orphan drug for NDM. This led to international discussions on affordability and willingness to reimburse mexiletine in the absence of background information that would justify such a price. Our objective was to calculate a cost-based price for mexiletine for adult patients with NDM based on detailed information on development costs.
METHODS
We calculated a fair price based on a cost-based pricing model for commercial mexiletine to treat adults with NDM using a recent European drug-pricing model as a framework to include actual costs incurred. Three scenarios were applied: 1 with minimum estimated costs, 1 with maximum estimated costs, and 1 with costs as if mexiletine was innovative.
RESULTS
The calculated fair price of mexiletine per patient per year (PPPY) is €452 for the minimum scenario and €1996 for the maximum scenario. By using hypothetical R&D costs used for innovative drugs, the price would be €6685 PPPY. In Europe, the list price of mexiletine ranges from €30 707-60 730 PPPY, based on 600 mg daily.
CONCLUSIONS
The current list price for mexiletine in Europe is manifold higher than any scenario of the cost-based models. Accounting for the reduced costs for clinical development in a repurposing scenario, the cost-based pricing model provides a fair commercial price range, which can be used as benchmark for pricing negotiations and/or reimbursement decisions.
Topics: Anti-Arrhythmia Agents; Commerce; Drug Repositioning; Europe; Humans; Mexiletine; Myotonia; Orphan Drug Production
PubMed: 34243835
DOI: 10.1016/j.jval.2021.02.004 -
Kardiologia Polska 2017Antiarrhythmic treatment of patients with recurrent ventricular tachyarrhythmia, in whom catheter ablation and amiodarone treatment were ineffective or contraindicated,...
BACKGROUND
Antiarrhythmic treatment of patients with recurrent ventricular tachyarrhythmia, in whom catheter ablation and amiodarone treatment were ineffective or contraindicated, is an unsolved clinical problem.
AIM
The study aims to evaluate the efficacy and tolerability of mexiletine in patients with recurrent ventricular tachyarrhythmias and/or electrical storm events, in whom standard treatment strategies failed to prevent ventricular tachyarrhythmia.
METHODS
We performed a retrospective cohort analysis of all patients treated with mexiletine for recurrent ventricular tachycardia and/or ventricular fibrillation in our institution between January 2011 and September 2015. The primary endpoints were total number of electrical storm events and ventricular tachycardia/ventricular fibrillation (VT/VF) episodes after the beginning of mexiletine therapy. Secondary endpoints were total number of implantable cardioverter-defibrillator (ICD) therapies and discontinuation of the therapy. Events were compared with a matched duration period before initiating mexiletine. Patients served as self-controls.
RESULTS
Seventeen patients were included in the study; 11 patients were males. Mean age was 64.2 ± 15.4 years. The median time of mexiletine treatment was eight months (interquartile range [IR]: 1-22 months). The mexiletine dose was 600 mg/day in 13 patients and 400 mg/day in four patients. In four patients the dose was modified during treatment in a range from 400 to 600 mg/day depending on clinical decision. Treatment with mexiletine significantly reduced the number of electrical storm events (14 episodes vs. two episodes; median and IR for 17 patients: 1 [0-1] vs. 0 [0-0], p = 0.0010), VT/VF episodes (285 vs. 74 episodes; median and IR for 17 patients: 7 [5-27] vs. 0 [0-5], p = 0.0115), and ICD interventions (317 interven-tions vs. nine interventions; median and IR for 17 patients: 10 [5-25] vs. 0 [0-2], p = 0.0006), in comparison with a matched period before initiation of treatment. In 14 out of 17 patients (82%) sufficient tolerability of mexiletine was observed. Only in three (18%) patients severe side effects of mexiletine treatment occurred requiring discontinuation of therapy.
CONCLUSIONS
Mexiletine was a sufficiently tolerated antiarrhythmic drug in short-term treatment of ventricular tachyarrhyth-mias in the studied population. Mexiletine may be effective in the treatment of recurring ventricular tachyarrhythmias or electrical storm events.
Topics: Aged; Aged, 80 and over; Anti-Arrhythmia Agents; Combined Modality Therapy; Defibrillators, Implantable; Drug Tolerance; Humans; Male; Mexiletine; Middle Aged; Recurrence; Retrospective Studies; Treatment Outcome; Ventricular Fibrillation
PubMed: 29057449
DOI: 10.5603/KP.2017.0189 -
The Cochrane Database of Systematic... Aug 2015Coronary artery disease is a major public health problem affecting both developed and developing countries. Acute coronary syndromes include unstable angina and... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Coronary artery disease is a major public health problem affecting both developed and developing countries. Acute coronary syndromes include unstable angina and myocardial infarction with or without ST-segment elevation (electrocardiogram sector is higher than baseline). Ventricular arrhythmia after myocardial infarction is associated with high risk of mortality. The evidence is out of date, and considerable uncertainty remains about the effects of prophylactic use of lidocaine on all-cause mortality, in particular, in patients with suspected myocardial infarction.
OBJECTIVES
To determine the clinical effectiveness and safety of prophylactic lidocaine in preventing death among people with myocardial infarction.
SEARCH METHODS
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 3), MEDLINE Ovid (1946 to 13 April 2015), EMBASE (1947 to 13 April 2015) and Latin American Caribbean Health Sciences Literature (LILACS) (1986 to 13 April 2015). We also searched Web of Science (1970 to 13 April 2013) and handsearched the reference lists of included papers. We applied no language restriction in the search.
SELECTION CRITERIA
We included randomised controlled trials assessing the effects of prophylactic lidocaine for myocardial infarction. We considered all-cause mortality, cardiac mortality and overall survival at 30 days after myocardial infarction as primary outcomes.
DATA COLLECTION AND ANALYSIS
We performed study selection, risk of bias assessment and data extraction in duplicate. We estimated risk ratios (RRs) for dichotomous outcomes and measured statistical heterogeneity using I(2). We used a random-effects model and conducted trial sequential analysis.
MAIN RESULTS
We identified 37 randomised controlled trials involving 11,948 participants. These trials compared lidocaine versus placebo or no intervention, disopyramide, mexiletine, tocainide, propafenone, amiodarone, dimethylammonium chloride, aprindine and pirmenol. Overall, trials were underpowered and had high risk of bias. Ninety-seven per cent of trials (36/37) were conducted without an a priori sample size estimation. Ten trials were sponsored by the pharmaceutical industry. Trials were conducted in 17 countries, and intravenous intervention was the most frequent route of administration.In trials involving participants with proven or non-proven acute myocardial infarction, lidocaine versus placebo or no intervention showed no significant differences regarding all-cause mortality (213/5879 (3.62%) vs 199/5848 (3.40%); RR 1.02, 95% CI 0.82 to 1.27; participants = 11727; studies = 18; I(2) = 15%); low-quality evidence), cardiac mortality (69/4184 (1.65%) vs 62/4093 (1.51%); RR 1.03, 95% CI 0.70 to 1.50; participants = 8277; studies = 12; I(2) = 12%; low-quality evidence) and prophylaxis of ventricular fibrillation (76/5128 (1.48%) vs 103/4987 (2.01%); RR 0.78, 95% CI 0.55 to 1.12; participants = 10115; studies = 16; I(2) = 18%; low-quality evidence). In terms of sinus bradycardia, lidocaine effect is imprecise compared with effects of placebo or no intervention (55/1346 (4.08%) vs 49/1203 (4.07%); RR 1.09, 95% CI 0.66 to 1.80; participants = 2549; studies = 8; I(2) = 21%; very low-quality evidence). In trials involving only participants with proven acute myocardial infarction, lidocaine versus placebo or no intervention showed no significant differences in all-cause mortality (148/2747 (5.39%) vs 135/2506 (5.39%); RR 1.01, 95% CI 0.79 to 1.30; participants = 5253; studies = 16; I(2) = 9%; low-quality evidence). No significant differences were noted between lidocaine and any other antiarrhythmic drug in terms of all-cause mortality and ventricular fibrillation. Data on overall survival 30 days after myocardial infarction were not reported. Lidocaine compared with placebo or no intervention increased risk of asystole (35/3393 (1.03%) vs 14/3443 (0.41%); RR 2.32, 95% CI 1.26 to 4.26; participants = 6826; studies = 4; I(2) = 0%; very low-quality evidence) and dizziness/drowsiness (74/1259 (5.88%) vs 16/1274 (1.26%); RR 3.85, 95% CI 2.29 to 6.47; participants = 2533; studies = 6; I(2) = 0%; low-quality evidence). Overall, safety data were poorly reported and adverse events may have been underestimated. Trial sequential analyses suggest that additional trials may not be needed for reliable conclusions to be drawn regarding these outcomes.
AUTHORS' CONCLUSIONS
This Cochrane review found evidence of low quality to suggest that prophylactic lidocaine has very little or no effect on mortality or ventricular fibrillation in people with acute myocardial infarction. The safety profile is unclear. This conclusion is based on randomised controlled trials with high risk of bias. However (disregarding the risk of bias), trial sequential analysis suggests that additional trials may not be needed to disprove an intervention effect of 20% relative risk reduction. Smaller risk reductions might require additional higher trials.
Topics: Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Bradycardia; Humans; Lidocaine; Myocardial Infarction; Randomized Controlled Trials as Topic; Ventricular Fibrillation
PubMed: 26295202
DOI: 10.1002/14651858.CD008553.pub2 -
Cureus Sep 2020Mirogabalin is a novel ligand for the α2δ subunit of voltage-gated calcium channels and is used to treat neuropathic pain in a similar manner to pregabalin. Although...
Mirogabalin is a novel ligand for the α2δ subunit of voltage-gated calcium channels and is used to treat neuropathic pain in a similar manner to pregabalin. Although the frequency of pregabalin-induced neutropenia has been reported as 0.3%-1%, mirogabalin-induced neutropenia has not previously been reported in the literature. Herein, we report what we believe is the first case of neutropenia induced by mirogabalin. A 77-year-old woman with squamous cell carcinoma of the lung had been taking mirogabalin at 10 mg/day for six weeks prior to admission to our hospital. She had received two courses of chemotherapy with carboplatin and nanoparticle albumin-bound (nab)-paclitaxel for lung cancer until four months before admission, followed by two courses of nivolumab until one month before admission. The patient was hospitalized for urinary tract infection (UTI), which improved with oral amoxicillin/clavulanic acid at 500/125 mg three times daily for five days (until the fifth hospital day). After that, she underwent rehabilitation to improve muscle strength. During rehabilitation, neutropenia (1,278/µL) was noted, acetaminophen and mexiletine were ceased, and filgrastim was started on hospital day 17. The neutrophil count was 755/µL on hospital day 18. Mirogabalin was discontinued on hospital day 19. The neutrophil count fell to 320/µL and 118/µL on hospital day 20 and day 21, respectively, and recovered to 1,064/µL on hospital day 24. Acetaminophen and mexiletine were resumed on hospital day 31 and neutropenia has not recurred since.
PubMed: 33029462
DOI: 10.7759/cureus.10182 -
Journal of the American Heart... May 2017Although atrial fibrillation (AF) is the most common abnormal heart rhythm and its prevalence continues to rise, there is a marked paucity of effective and safe...
BACKGROUND
Although atrial fibrillation (AF) is the most common abnormal heart rhythm and its prevalence continues to rise, there is a marked paucity of effective and safe antiarrhythmic drugs for AF. This study was done to test whether combined use of dofetilide and mexiletine exhibits not only a synergistic effect on AF suppression but also a safer profile in drug-induced ventricular proarrhythmias.
METHODS AND RESULTS
The effects of dofetilide plus mexiletine on atrial effective refractory period (ERP), AF inducibility, QT, and QT-related ventricular arrhythmias were studied using the isolated arterially perfused rabbit atrial and ventricular wedge preparations. Dofetilide or mexiletine alone mildly to moderately prolonged atrial ERP, but their combined use produced a markedly rate-dependent increase in atrial ERP. Dofetilide (3 nmol/L) plus mexiletine (10 μmol/L) increased the ERP by 28.2% from 72.2±5.7 to 92.8±5.9 ms (n=9, <0.01) at a pacing rate of 0.5 Hz and by 94.5% from 91.7±5.2 to 178.3±12.0 ms (n=9, <0.01) at 3.3 Hz. Dofetilide plus mexiletine strongly suppressed AF inducibility. On the other hand, dofetilide at 10 nmol/L produced marked QT and T prolongation, steeper QT-BCL and T-BCL slopes, and induced early afterdepolarizations and torsade de pointes in the ventricular wedges. Mexiletine at 10 μmol/L reduced dofetilide-induced QT and T prolongation, QT-BCL and T-BCL slopes, and abolished early afterdepolarizations and torsade de pointes.
CONCLUSIONS
In rabbits, combined use of dofetilide and mexiletine not only synergistically increases atrial ERP and effectively suppresses AF inducibility, but also markedly reduces QT liability and torsade de pointes risk posed by dofetilide alone.
Topics: Action Potentials; Animals; Anti-Arrhythmia Agents; Atrial Fibrillation; Drug Synergism; Drug Therapy, Combination; Female; Heart Atria; Heart Rate; Heart Ventricles; In Vitro Techniques; Long QT Syndrome; Male; Mexiletine; Phenethylamines; Rabbits; Refractory Period, Electrophysiological; Risk Assessment; Sulfonamides; Time Factors; Torsades de Pointes
PubMed: 28522677
DOI: 10.1161/JAHA.117.005482 -
Frontiers in Pharmacology 2024Na1.4 is a voltage-gated sodium channel subtype that is predominantly expressed in skeletal muscle cells. It is essential for producing action potentials and stimulating... (Review)
Review
Na1.4 is a voltage-gated sodium channel subtype that is predominantly expressed in skeletal muscle cells. It is essential for producing action potentials and stimulating muscle contraction, and mutations in Na1.4 can cause various muscle disorders. The discovery of the cryo-EM structure of Na1.4 in complex with β1 has opened new possibilities for designing drugs and toxins that target Na1.4. In this review, we summarize the current understanding of channelopathies, the binding sites and functions of chemicals including medicine and toxins that interact with Na1.4. These substances could be considered novel candidate compounds or tools to develop more potent and selective drugs targeting Na1.4. Therefore, studying Na1.4 pharmacology is both theoretically and practically meaningful.
PubMed: 38725668
DOI: 10.3389/fphar.2024.1378315 -
Clinical and Translational Science Aug 2022Lamotrigine, approved for use as an antiseizure medication as well as the treatment of bipolar disorder, inhibits sodium channels in the brain to reduce repetitive...
Lamotrigine, approved for use as an antiseizure medication as well as the treatment of bipolar disorder, inhibits sodium channels in the brain to reduce repetitive neuronal firing and pathological release of glutamate. The shared homology of sodium channels and lack of selectivity associated with channel blocking agents can cause slowing of cardiac conduction and increased proarrhythmic potential. The Vaughan-Williams classification system differentiates sodium channel blockers using biophysical properties of binding. As such, Class Ib inhibitors, including mexiletine, do not slow cardiac conduction as measured by the electrocardiogram, at therapeutically relevant exposure. Our goal was to characterize the biophysical properties of Na 1.5 block and to support the observed clinical safety of lamotrigine. We used HEK-293 cells stably expressing the hNa 1.5 channel and voltage clamp electrophysiology to quantify the potency (half-maximal inhibitory concentration) against peak and late channel current, on-/off-rate binding kinetics, voltage-dependence, and tonic block of the cardiac sodium channel by lamotrigine; and compared to clinically relevant Class Ia (quinidine), Ib (mexiletine), and Ic (flecainide) inhibitors. Lamotrigine blocked peak and late Na 1.5 current at therapeutically relevant exposure, with rapid kinetics and biophysical properties similar to the class Ib inhibitor mexiletine. However, no clinically meaningful prolongation in QRS or PR interval was observed in healthy subjects in a new analysis of a previously reported thorough QT clinical trial (SCA104648). In conclusion, the weak Na 1.5 block and rapid kinetics do not translate into clinically relevant conduction slowing at therapeutic exposure and support the clinical safety of lamotrigine in patients suffering from epilepsy and bipolar disorder.
Topics: Anticonvulsants; Flecainide; HEK293 Cells; Humans; Lamotrigine; Mexiletine; Sodium Channel Blockers; Sodium Channels
PubMed: 35579204
DOI: 10.1111/cts.13311 -
Neuromuscular Disorders : NMD Nov 2021The MYOMEX study was a multicentre, randomised, double-blind, placebo-controlled, cross-over study aimed to compare the effects of mexiletine vs. placebo in patients... (Randomized Controlled Trial)
Randomized Controlled Trial
The MYOMEX study was a multicentre, randomised, double-blind, placebo-controlled, cross-over study aimed to compare the effects of mexiletine vs. placebo in patients with myotonia congenita (MC) and paramyotonia congenita (PC). The primary endpoint was the self-reported score of stiffness severity on a 100 mm visual analogic scale (VAS). Mexiletine treatment started at 200 mg/day and was up-titrated by 200 mg increment each three days to reach a maximum dose of 600 mg/day for total treatment duration of 18 days for each cross-over period. The modified intent-to-treat population included 25 patients (13 with MC and 12 with PC; mean age, 43.0 years; male, 68.0%). The median VAS score for mexiletine was 71.0 at baseline and decreased to 16.0 at the end of the treatment while the score did not change for placebo (81.0 at baseline vs. 78.0 at end of treatment). A mixed effects linear model analysis on ranked absolute changes showed a significant effect of treatment (p < 0.001). The overall score of the Individualized Neuromuscular Quality of Life questionnaire (INQoL) was significantly improved (p < 0.001). No clinically significant adverse events were reported. In conclusion, mexiletine improved stiffness and quality of life in patients with nondystrophic myotonia and was well tolerated.
Topics: Adult; Aged; Cross-Over Studies; Double-Blind Method; Female; Humans; Male; Mexiletine; Middle Aged; Myotonia; Myotonia Congenita; Myotonic Disorders; Quality of Life; Treatment Outcome
PubMed: 34702654
DOI: 10.1016/j.nmd.2021.06.010 -
Pain May 2017Erythromelalgia (EM) is a rare neurovascular disorder characterized by intermittent severe burning pain, erythema, and warmth in the extremities on heat stimuli. To...
Erythromelalgia (EM) is a rare neurovascular disorder characterized by intermittent severe burning pain, erythema, and warmth in the extremities on heat stimuli. To investigate the underlying pathophysiology, peripheral axonal excitability studies were performed and changes with heating and therapy explored. Multiple excitability indices (stimulus-response curve, strength-duration time constant (SDTC), threshold electrotonus, and recovery cycle) were investigated in 23 (9 EMSCN9A+ and 14 EMSCN9A-) genetically characterized patients with EM stimulating median motor and sensory axons at the wrist. At rest, patients with EM showed a higher threshold and rheobase (P < 0.001) compared with controls. Threshold electrotonus and current-voltage relationships demonstrated greater changes of thresholds in both depolarizing and hyperpolarizing preconditioning electrotonus in both EM cohorts compared with controls in sensory axons (P < 0.005). When average temperature was raised from 31.5°C to 36.3°C in EMSCN9A+ patients, excitability changes showed depolarization, specifically SDTC significantly increased, in contrast to the effects of temperature previously established in healthy subjects (P < 0.05). With treatment, 4 EMSCN9A+ patients (4/9) reported improvement with mexiletine, associated with reduction in SDTC in motor and sensory axons. This is the first study of primary EM using threshold tracking techniques to demonstrate alterations in peripheral axonal membrane function. Taken together, these changes may be attributed to systemic neurovascular abnormalities in EM, with chronic postischaemic resting membrane potential hyperpolarization due to Na/K pump overactivity. With heating, a trigger of acute symptoms, axonal depolarization developed, corresponding to acute axonal ischaemia. This study has provided novel insights into EM pathophysiology.
Topics: Adolescent; Adult; Aged; Axons; Case-Control Studies; Child; Computer Simulation; Erythromelalgia; Female; Humans; Male; Middle Aged; Models, Biological; Mutation; NAV1.7 Voltage-Gated Sodium Channel; Neural Conduction; Pain; Severity of Illness Index; Temperature; Young Adult
PubMed: 28134657
DOI: 10.1097/j.pain.0000000000000856