[Dose-response study of bunazosin in the treatment of light-to-moderate arterial hypertension].
BACKGROUND
The antagonists of alpha-adrenergic receptors were introduced in the therapy of arterial hypertension in 1950, but have had limited use due to the poor efficacy and safety of some drugs belonging to this pharmacological class. A recent molecule from this class, bunazosin, is a highly selective alpha 1-antagonist, whose long half-life allows a single daily administration. The aim of this study was to identify the minimum effective dose of bunazosin in the treatment of mild-moderate arterial hypertension.


METHODS
Patients of both sexes, aged over eighteen years, suffering from mild/moderate essential arterial hypertension were admitted to the study. The experimental design was controlled between patients; and the study was carried out in accordance with the principles of Helsinki anf Tokyo. Dosage was of 3 and 6 mg/day per os; after 2 weeks' treatment, if DBP in clinostatism > or = 95 mmHg, the dose was doubled. Treatment lasted four weeks.


RESULTS
At the end of treatment, in the group of patients initially treated with 3 mg/day, SBP, in clinostatism fell by 10.0% and DBP by 8.4% (p < 0.01 between times); in the group of patients initially treated with 6 mg/day, the reductions were of 9.2% and 6.5% respectively (p < 0.01 between times). Heart rate, electrocardiograph traces and laboratory parameters showed no clinically significant modifications. The safety profile of the treatment was excellent in 80% of the patients treated overall.


CONCLUSIONS
This study allowed the minimum effective dose of bunazosin, equal to 3-6 mg/day, to be identified, as well as confirming the antihypertensive efficacy of the drug and its ample safety margin. In fact, this range of daily dosage led to a fall in pressure values, without causing clinically significant alterations of heart rate, electrocardiograph traces and laboratory parameters.


CONCLUSIONS
In conclusions, in mild/moderate arterial hypertension, bunazosin in monotherapy at the dosage of 3-6 mg/day, is an effective and safe treatment.
Marchegiano
R
R
II Facoltà di Medicina e Chirurgia, I Clinica Medica, Napoli.
Lamenza
F
F
Sarno
D
D
Tozzi
N
N
Fontana
D
D
De Luca
N
N
D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D004305:Dose-Response Relationship, Drug; D004341:Drug Evaluation; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D008297:Male; D011799:Quinazolines / Q000008:administration & dosage / Q000627:therapeutic use*
D000317:Adrenergic alpha-Antagonists; D011799:Quinazolines; C018176:bunazosin
Studio dose-risposta sulla bunazosina nel trattamento dell'ipertensione arteriosa lieve-moderata.