RESUMEN
In 30 patients with mild hypertension (diastolic blood pressure, 95 to 105 mmHg), the antihypertensive effect of rilmenidine 1 mg was compared in a double-blind study, with the effect of hydrochlorothiazide 25 mg. Patients not satisfactorily controlled received a combined therapy on the same doses of the two drugs used. Rilmenidine and hydrochlorothiazide induced a significant reduction (p = 0.01) of supine and erect systolic/diastolic blood pressure 23 hours after drug intake with no change in heart rate. This effect was due to a reduction in cardiac output (bioimpedance method) significant (p = 0.05) only for rilmenidine. Both drugs controlled the increase of effort systolic blood pressure in comparison with placebo on systemic vascular resistance treadmill exercise testing. Effort cardiac output was increased by each treatment in comparison with baseline values. Both at rest and on exertion, there was no effect on systemic vascular resistance induced by the two drugs. In a second group of 10 patients with moderate hypertension (diastolic blood pressure, 105 to 115 mmHg), rilmenidine 1 mg was administered in order to evaluate its efficacy and hemodynamic effects (bioimpedance and radionuclide ventriculography), at rest and during a lying cycloergometer effort test. The drug induced a significant decrease in blood pressure at rest and on exertion four hours after drug intake. This effect was due to a reduction (p = 0.05) in systemic vascular resistance, whereas cardiac output and heart rate remained unchanged. Our results show that the reduction in systolic/diastolic blood pressure induced by rilmenidine 1 mg is comparable with that induced by the well-known antihypertensive drug hydrochlorothiazide in mild hypertension. In moderate hypertension, the 1-mg dose appears to be insufficient in controlling the blood pressure in all patients. The drug exerts its antihypertensive effect through the normalization of the altered hemodynamic parameters of hypertension (high cardiac output and/or increased systemic vascular resistance). Rilmenidine also respects the physiologic increase in blood pressure and cardiac output on exertion.
Asunto(s)
Antihipertensivos/farmacología , Presión Sanguínea/efectos de los fármacos , Hipertensión/fisiopatología , Oxazoles/farmacología , Esfuerzo Físico , Adulto , Antihipertensivos/uso terapéutico , Método Doble Ciego , Prueba de Esfuerzo , Femenino , Humanos , Hidroclorotiazida/farmacología , Hipertensión/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Oxazoles/uso terapéutico , Distribución Aleatoria , Descanso , RilmenidinaRESUMEN
In order to verify the anti-ischaemic effect of a new beta-blocking agent, bisoprolol, a double blind parallel groups trial was carried out in comparison with verapamil. 26 patients with a history of spontaneous and/or effort angina were studied. After a two-week treatment with placebo, they were randomized in two groups. One group was treated for 4 weeks with bisoprolol 10 mg o.d. and for the following 4 weeks with bisoprolol 20 mg o.d. The other group received verapamil 80 mg t.i.d. for the first 4 weeks and 120 mg t.i.d. for the remaining 4 weeks. Throughout the study isosorbide dinitrate 20 mg b.i.d. was administered and sublingual nitroglycerin was allowed when necessary. 21 patients completed the study. Both bisoprolol and verapamil significantly reduced the number of angina episodes and nitroglycerin tablets consumption, as well as ischaemic episodes recorded on Holter ECG. The total number and severity of ectopic ventricular beats were reduced too. On multistage treadmill exercise test, both drugs increased effort time and time to ST depression = 1 mm, and reduced ST depression and double-product. The effect of bisoprolol on double product was greater than that of verapamil because of the better control of heart rate. The relationship ST/double product suggested that beta-blockers act essentially through the reduction of myocardial oxygen consumption and verapamil possibly with an additive effect on coronary circulation. Radionuclide ventriculography showed no deterioration of rest ventricular function with both drugs. In conclusion, bisoprolol and verapamil showed a satisfactory anti-ischaemic effect, with good tolerability.