Experience with oral mexiletine in primary erythromelalgia in children

Primary erythromelalgia is characterized by burning pain, redness, and warmth in the extremities. We present two cases of primary erythromelalgia both of whom presented with a history of several months of severe burning pain in both hands and feet. Both patients had received multiple pain medications with no improvement in symptoms. Pain was relieved by putting affected parts in ice cold water, which resulted in immersion injury of the affected parts. Both patients stopped taking part in school and social activities. We tried oral mexiletine, a class Ib antiarrythmic agent, in view of its reported role in various chronic painful conditions. Dramatic improvement was observed with its use. Both patients improved after several weeks of use, and there were fewer soaking episodes. We observed no adverse effects with mexilitine therapy

Uso de antiarrítmicos na presença de disfunçäo vantricular esquerda / Antiarrhythmic drugs in patients with left ventricular dysfunction

Com o aumento da sobrevida da populaçäo nos últimos anos e com a melhoria no tratamento do infarto agudo do miocárdio, maior número de pacientes apresenta-se na clínica com maior chance de apresentar arritmias cardíacas de gravidade variável.Muitos desses pacientes necessitam tratamento anti-arrítmico, que, na maioria dos centros, ainda é baseado na administraçäo de medicamentos.Os pacientes sobreviventes de morte súbita cardíaca, ou com miocardiopatia dilatada de origem isquêmica ou idiopática, apresentam graus variáveis de disfunçäo ventricular.Quanto mais comprometida a fraçäo de ejeçäo, pior o grau funcional desses pacientes e maiores riscos de arritmias potencialmente letais, ameaçadoras à vida.Do ponto de vista anatomopatológico, a disfunçäo ventricular caracteriza-se por células isquêmica, entremeadas por células saudáveis e áreas de necrose.É justamente nesse substrato que as arritmias se origianm e é exatamente sobre esta regiäo que os fármaco antiarrítmicos exercem seus efeitos eletrofisiológicos.Há vários estudos demonstrando que quando pior o estado da funçäo ventricular, menor a eficácia desses medicamentos.Em outras palavras, exatamente os pacientes com arritmia mais grave, que mais necessitam do efeito antiarrítmico desses agentes, säo os que menos se beneficiam.A Maioria dos medicamentos disponíveis para o tratamento da arritmias cardíacas exerce algum efeito depressor da funçäo ventricular.Quanto maior esse efeito depressor da funçäo ventricular é mais acentuada nos pacientes com piores graus funcionais e, por essa razäo, devem ser prescritos com cautela nessa populaçäo...

Prophylactic use of mexiletine in the elderly with acute myocardial infarction.

A double blind randomised study comparing the effects of oral mexiletine and placebo given to elderly patients (65 years and older) immediately following hospital admission with suspected myocardial infarction (MI) is described. The study comprised one hundred and fifty-four patients of which 74 had confirmed myocardial infarction according to the diagnostic criteria of the study. Eighty patients without definite evidence of myocardial infarction were subsequently excluded from the study. Thirty-three patients (44.5%) with confirmed MI treated with mexiletine, compared with 41 (51%) in the placebo group showed no significant difference in mortality at 48 hours and 14 days. The mexiletine treated group showed a significant reduction (p less than 0.05) in certain forms of ventricular dysrhythmias. Six of these patients (18%) taking mexiletine had the drug withdrawn because of possible adverse drug reactions compared with two (4.8%) of the placebo group. None of the patients withdrawn because of possible adverse drug reactions had any long term side effect. Mild confusion observed in one patient was reversed after withdrawal of therapy. Results of this study indicate the safety of mexiletine as an anti-arrhythmic drug and its efficacy in suppression of certain ventricular dysrhythmias in the elderly with acute myocardial infarction. The overall mortality rate in both groups (mexiletine and placebo) remained unchanged.

Tratamiento sintomático de la miocarditis chagásica crónica / Symptomatic treatment of the chronic Chagasic myocarditis

Analiza la acción farmacológica, efectividad, dosis de administración y efectos colaterales de diversas drogas antiarrítmicas clasificadas del acuerdo a sus efectos electrofisiológicos (quinidina y procainamida, disopiramida, agentes betabloqueantes, mexiletine, amiodarona, y, verapamil), y suelen indicarse para el tratamiento de la insuficiencia cardíaca, las arritmias y los trastornos de conducción en pacientes chagásicos