Bradyarrhythmia after treatment with atenolol and mirtazapine in a cat with hypertrophic cardiomyopathy.

A nine-year-old spayed female domestic shorthair cat with a previous diagnosis of hypertrophic cardiomyopathy and treated for one month with atenolol (6.25 mg q 12 h) was referred for respiratory distress and anorexia. The cat was diagnosed with pulmonary oedema secondary to obstructive hypertrophic cardiomyopathy. After stabilisation, she was discharged with furosemide (1 mg/kg q 12 h), clopidogrel (18.75 mg q 24 h), atenolol (6.25 mg q 12 h), and mirtazapine (2 mg/cat q 24 h) to increase appetite. At recheck, the cat was lethargic and presented with severe bradycardia with a junctional escape rhythm and ventriculoatrial conduction. The mirtazapine was discontinued due to its possible side-effects on cardiac rhythm. After three days, the atenolol was halved because the bradyarrhythmia was still present. After 10 days, the rhythm returned to sinus; atenolol was reintroduced twice daily with no further side-effects. The absence of a sinus rhythm with a junctional escape rhythm and P' retroconduction is compatible with a third-degree sinus block or a sinus standstill; the differentiation of these rhythm disturbances is impossible, based on the surface electrocardiogram (ECG). The sinus rhythm was restored after mirtazapine was withdrawn. However, it is not possible to rule out the role of the atenolol or the combined effect of the two drugs. The cat was affected by hypertrophic cardiomyopathy, and the role of myocardial remodelling cannot be excluded. This is the first time that a bradyarrhythmia consequent to the treatment with atenolol and mirtazapine was described in a cat.

Bioequivalence Study of Atenolol Tablets in Healthy Chinese Subjects Under Fasting and Fed Conditions.

Atenolol, a cardioselective ß1-blocker, exhibits efficacy in treating cardiovascular diseases. We conducted a single-center, randomized, open, single-dose, 2-preparation, 2-cycle, 2-sequence, double-crossover trial with a 7-day washout period to investigate the pharmacokinetics, bioequivalence (BE), and safety of test and reference atenolol tablets (25 mg) in healthy Chinese volunteers. Forty-eight healthy participants were randomized into the fasting and fed arms. After administering a single oral dose of the test or reference formulation (25 mg), plasma atenolol concentrations were measured using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were obtained from concentration-time profiles. In total, 23 and 24 individuals were included in the fasting and fed arms, respectively. The mean concentration-time profiles for both formulations were similar, and Cmax, AUC0-t, and AUC0-∞ were within the BE range of 80%-125%. Thirteen adverse events (AEs) were observed in 7 participants in the fasting arm; 1 withdrew from the trial early owing to an AE. In the fed arm, 20 AEs were observed in 8 participants, and none withdrew from the trial. All adverse reactions were grade I, with no serious AEs or deaths. Therefore, the 2 tablets are bioequivalent in healthy Chinese individuals under fasting and fed conditions, supporting their further clinical development.

Atenolol, una droga mal prescripta / Atenolol, a wrong prescripted drug

Se realizó un estudio cuantitativo, retrospectivo y descriptivo para determinar el la incorrecta prescripción del atenolol en el área sur de Morón, se distribuyeron los pacientes según sexo, edad, criterio de prescripción, se precisó la dosis indicada, se determinó el tiempo de duración de la terapia y se describieron las interacciones y reacciones medicamentosas encontradas. Se determinó que el sexo más afectado fue el masculino con un 50,87 por ciento, el grupo de edad más afectado fue el de 25 a 59 con un 54, 31%, el criterio que prevaleció fue la epilepsia con un total de 70 pacientes y un 60,74 por ciento, la dosis que con mayor frecuencia se usó fue la de 3 tabletas diarias, la interacción medicamentosa más frecuente fue con el fenobarbital en un 70,69 por ciento y la reacción medicamentosa más común fue el ras cutáneo para un 14, 65 por ciento.

An economic evaluation of antihypertensive therapies based on clinical trials

OBJECTIVE: Hypertension is a major issue in public health, and the financial costs associated with hypertension continue to increase. Cost-effectiveness studies focusing on antihypertensive drug combinations, however, have been scarce. The cost-effectiveness ratios of the traditional treatment (hydrochlorothiazide and atenolol) and the current treatment (losartan and amlodipine) were evaluated in patients with grade 1 or 2 hypertension (HT1-2). For patients with grade 3 hypertension (HT3), a third drug was added to the treatment combinations: enalapril was added to the traditional treatment, and hydrochlorothiazide was added to the current treatment. METHODS: Hypertension treatment costs were estimated on the basis of the purchase prices of the antihypertensive medications, and effectiveness was measured as the reduction in systolic blood pressure and diastolic blood pressure (in mm Hg) at the end of a 12-month study period. RESULTS: When the purchase price of the brand-name medication was used to calculate the cost, the traditional treatment presented a lower cost-effectiveness ratio [US$/mm Hg] than the current treatment in the HT1-2 group. In the HT3 group, however, there was no difference in cost-effectiveness ratio between the traditional treatment and the current treatment. The cost-effectiveness ratio differences between the treatment regimens maintained the same pattern when the purchase price of the lower-cost medication was used. CONCLUSIONS: We conclude that the traditional treatment is more cost-effective (US$/mm Hg) than the current treatment in the HT1-2 group. There was no difference in cost-effectiveness between the traditional treatment and the current treatment for the HT3 group.

Análisis crítico de un artículo: Atenolol, ¿primera elección en el tratamiento de la hipertensión? / Critical appraissal: Should atenolol be the first choice for primary hypertension? Atenolol in hypertension: is it a wise choice? Lancet 2004; 364: 1684-89

Background: Atenolol is one of the most widely used beta blockers clinically, and has often been used as a reference drug in randomized controlled trials of hypertension. However, questions have been raised about atenolol as the best reference drug for comparisons with other antihypertensives. Thus, our aim was to systematically review the effect of atenolol on cardiovascular morbidity and mortality in hypertensive patients. Methods: Reports were identified through searches of The Cochrane Library, MEDLINE, relevant textbooks, and by personal communication with established researchers in hypertension. Randomized controlled trials that assessed the effect of atenolol on cardiovascular morbidity or mortality in patients with primary hypertension were included. Findings: We identified four studies that compared atenolol with placebo or no treatment, and five that compared atenolol with other antihypertensive drugs. Despite major differences in blood pressure lowering, there were no outcome differences between atenolol and placebo in the four studies, comprising 6,825 patients, who were followed up for a mean of 4.6 years on all-cause mortality (relative risk 1.01 [95% CI 0.89-1.15]), cardiovascular mortality (0.99[0.83-1.18]), or myocardial infarction (0.99 [0.83-1.19]). The risk of stroke, however, tended to be lower in the atenolol than in the placebo group (0.85 [0.72-1.01]). When atenolol was compared with other antihypertensives, there were no major differences in blood pressure lowering between the treatment arms. Our meta-analysis showed a significantly higher mortality (1.13[1.02-1.25]) with atenolol treatment than with other active treatment, in the five studies comprising 17,671 patients who were followed up for a mean of 4.6 years. Moreover, cardiovascular mortality also tended to be higher with atenolol treatment than with other antihypertensive treatment. Stroke was also more frequent with atenolol treatment. Interpretation: Our results cast doubts ...

Angina estável: abordagem por um novo fármaco - Ivabradina / Stable angina: a new drug approcach - Ivabradine

O tratamento atual da doença coronariana crônica - angina estável, envolve o uso de medicamentos com ação hemodinâmica, como os nitratos, os betabloqueadores (BB) e os bloqueadores dos canais de cálcio (BCC). O presente artigo apresenta Ivabradina, um novo medicamento para a abordagem da angina estável, revisa o seu modo de ação e os resultados da literatura médica recente.

Analysis of left ventricular function by radionuclide ventriculogram in hypertensive patients treated with atenolol

The myocardial effects of a daily oral dose of atenolol were studied by radionuclide multitriggered ventriculogram in 10 patients (7 men and 3 women) with mild to moderate essential hypertension, aged 29 to 53 years (mean 43) at rest and during exercise. Before and after two months of treatment with 100 mg/day orally of atenolol, the following variables were recordedÑ systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), ejection fraction (EF), peak filling rate (PFR) and peak ejection rate (PER). Beta-blockade treatment caused a significant drop in SBP and DBP, both at rest and during exerciseñ HR slowed down at rest and during exercise. PFR diminished at rest and during exercise. PER was reduced at rest and during exercise (p < 0.001). No significant changes in EF were observed after treatment with atenolol. In conclusion,k atenolol impaired left ventricular relaxation in spite of the drop in blood pressure

Comparación del efecto antihipertensivo de verapamil y atenolol / Comparison of the antihypertensive effect of verapamil and atenolol

Se realizó un estudio clínico en tres centros hospitalarios, en 24 pacientes con hipertensión arterial esencial grados I o II de la clasificación de la OMS, 14 mujeres y 10 hombres, con edad promedio de 47.5 años. El estudio fue doble ciego cruzado utilizando placebo, verapamil 240 mg y atenolol 100 mg al día, en cápsulas de idéntica presentación. El tiempo total de estudio fue de 12 semanas en cada paciente, dos semanas de "lavado" previo, cuatro semanas de uno de los medicamentos, un segundo "lavado" de dos semanas y otro periodo de tratamiento de otras cuatro semanas con el medicamento alterno. Se revisó a los pacientes en la consulta externa y se efectuaron análisis de laboratorio de rutina, radiografía de tórax inicial, electrocardiogramas y ecocardiogramas modo M y bidimensional, antes y después de la administración de cada fármaco. Se logró el control de la hipertensión en el 80 por ciento de los pacientes con verapamil y en el 71 por ciento con atenolol, sin diferencia significativa entre ellos, tanto en clino como en ortostatismo. La frecuencia cardíaca disminuyó en forma moderada, siendo mayor la disminución con atenolol. Se presentó bradicardia sinusal en tres casos con verapamil y en cuatro con atenolol. En ninguna ocasión apareción bloqueo A-V en el ECG. No hubieron efectos adversos con el verapamil y sólo en un paciente con atenolol. No se presentaron alteraciones en los ecocardiogramas ni en los análisis de laboratorio. Por el presente estudio se concluye que tanto el verapamil como el atenolol lograron el control adecuado de la hipertensión en la mayoría de los enfermos, sin efectos indeseables con el primero y mínimos con el segundo, sin acción inotrópica negativa jusgada por escocardiografía

Anemia sideroblástica adquirida y colestasis en un paciente hipertiroideo tratado con metimazol y atenolol / Acquired sideroblastic anemia and cholestasis in a hyperthyroid patient treated with methimazole and atenolol

Se describe un paciente de 62 años quien padeció de hipertiroidismo autoinmune, siendo tratado con metimazol y atenolol. Diez días después del inicio del tratamiento comenzó con prurito, icterícia y coluria. Se suspendieron ambos y se le administro iodo radioactivo. Dos meses después Ia bilirrubina directa aicanzó 35 mg por ciento. La colangiografía endoscópica retrógrada evidenció vías biliares extrahepáticas normales. Una biopsia del hígado mostró marcada colestasis, especialmente en la zona centrolobulillar, con un discreto infiltrado de células mononucleares en los espacios portales. Junto con el comienzo de la enfermedad presentó anemia. La aspiración de la médula ósea mostró rica celularidad, sideroblastos con un 10 por ciento de formas anilladas e incremento de hierro extracorpuscular. La evolución del paciente fue satisfactoria. A dieciocho meses del comienzo de la enfermedad se hallaba asintomático, no presentando ningún signo físico o humorai patológico. Una nueva punción de la médula ósea resulto normal. La severa colestasis intrahepática sufrida por el paciente, estaría relacionada con una reacción adversa ai metimazoi. Se discute la etio-fisiopatogenia de la anemia siderobiástica reversible.

Influência da cirurgia de revascularização miocárdica com circulação extracorpórea sobre a farmacocinética do propranolol e do atenolol / Influence of Coronary Artery Bypass Grafting Surgery Employing Cardiopulmonary Bypass in the Pharmacokinetics of Propranolol and Atenolol

Níveis plasmáticos e farmacocinética de beta-bloqueadores podem ser alterados por hipotermia e circulação extracorpórea (H-CEC). Avaliou-se, em pacientes submetidos a revascularização miocárdica (RM) com H-CEC, a farmacocinética do propranolol (n=11) e do atenolol (n=8) nos períodos pré e pós-operatório. Observou-se aumento da meia vida biológica e volume de distribuição apenas para o propranolol. O clearance total permaneceu inalterado para os dois fármacos e ocorreu aumento da concentração plasmática de propranolol do início até o final da H-CEC. Os resultados mostram que a RM com H-CEC induz alterações farmacocinéticas diferentes para o propranolol e o atenolol / Plasma levels and pharmacokinetics of betablockers may be altered by hypothermic cardiopulmonary bypass (H-CPB). We evaluated the pharmacokinetics of propranolol (n=11) and atenolol (n=8) pre and postoperatively in patients submitted to coronary artery bypass grafting surgery (CABG) employing H-CPB. Increase of biological half-life and volume of distribution was observed only for propranolol. The total clearance remained unchanged for both drugs and an increase in plasma propranolol was observed from the beginning to the end of H-CPB. Data obtained show that CABG employing H-CPB influences the propranolol and atenolol pharmacokinetics in distinct ways.