Eficácia anti-hipertensiva e tolerabilidade do cloridrato de prazosina de liberaçäo lenta. Estudo multicêntrico brasileiro / Anti-hypertensive efficacy and tolerability of sustained-release prazosin hydrochloride. A Brazilian multicenter study

RESUMO

Objetivo: Avaliar o efeito anti-hipertensivo e a tolerabilidade de dose única diária de cloridrato de prazosina de liberaçäo lenta (SR). Casuística e Métodos: 1393 portadores de hipertensäo arterial sistêmica primária (HAS) leve (644 pacientes e moderada (749 pacientes), com média etária de 47,63 anos, sendo 745 (53,52%) do sexo masculino, 1011 (72,84%) brancos e 279 (20,1%) negros. De acordo com protocolo multicêntrico aberto näo comparativo, os pacientes receberam cloridrato de prozosina SR em dose inicial de 1 mg, ajustada até máximo de 6 mg, de acordo com a resposta (objetivo = pressäo arterial diastólica (PAD) < ou = 90 mmHg), por prazo de 4 semanas. Resultados: A dose média diária foi de 2,08 mg, em tomada única. Ao final do estudo, 1274 (91,46%) pacientes atingiram PAD < ou = 90 mmHg, sendo 624 do grupo HAS leve e 650 do HAS moderada. O número de pacientes sob controle nas 3 primeiras semanas foi de 426 (1ª semana), 844 (2ª semana) e 1147 (3ª semana). APAD reduziu-se da média de 104 ñ 5 mmHg para a de 88 ñ 8 mmHg (p < 0,05). A freqüência cardíaca variou da média de 82 ñ 9 bpm pré-tratametno para 80 ñ 8 bpm na 4ª semana. Reaçöes adversas foram reconhecidas em 377 (27,06%) pacientes, total de 444 eventos, sendo mais freqüente a associaçäo de vertigem, tontura e lipotímia. Apenas 8 (2,12%) pacientes necessitaram reduzir as doses de cloridrato de prazosina SR e 5 (1,32%) tiveram de abandonar o estudo pelos efeitos indesejáveis da droga. Conclusäo: Cloridrato de prazosina SR em tomada única diária parece ser real avanço no tratamento da HAS leve e moderada, facilitando-o sem perda da eficácia e com boa tolerabilidade

ABSTRACT

Purpose: To evaluate the efficacy and tolerability of a single daily dose of sustained-release (SR) formulation of prazosin hydrocloride. Patients and Methods: 1393 outpatients in a multicenter open comparative trial. 644 patients had mild hypertension and 749 patients had moderate hypertension. The mean age was 47.63 years, 745 (53.52%) were male, 1011 (72.84%) white and 279 (20.1%) black. The patients received prazosin hydrocloride SR during 4 weeks in an initial dose of 1 mg, adjusted to a maximum of 6 mg in order to decrease the diastolic blood pressure (DBP) to 90 mmHg or less. Results: The mean daily dose was 2.08 mg. At the end of the study, 1274 (91.46%) patients had DBP £ 90 mmHg or less. 624 patients were in the mild hypertension group and 650 patients were in the moderate hypertension group. The number of patients under DBP control in the first three weeks was 426 (first week), 844 (second week) and 1147 (third week). The DBP decreased from the mean value of 104 ± 5 mmHg to 88 ± 8 mmHg (p < 0.05)’. The mean heart rate ranged from 82 ± 9 beats/min (pre-treatment) to 80 8 beats/min (fourth week). Adverse effects were identified in 377 (27.06%) patients, total of 444 episodes, the more frequent being dizziness. Only 8 (2.12%) patients had to reduce the doses of prazosin hydrocloride SR and 5 (1.32% ) had to discontinue the treatment on account of the adverse effects of the drug. Conclusion: Prazosin hydrocloride SR in a single daily dose seems to be an advance in the treatment of patients with mild and moderate hypertension.