Effects of hydrochlorothiazide combined with amiloride in atenolol-resistant hypertensive patients

Twenty hypertensive outpatients WHO stage I or II, with supine diastolic blood pressure greater than or equal to 95 mmHg at the end of a 4-week treatment period with atenolol (Tenormin) 100 mg daily, continued atenolol in free association with half a tablet of Moduretic (i.e., hydrochlorothiazide 25 mg + amiloride 2.5 mg) for a further 4 weeks. Atenolol monotherapy induced a drop of systolic blood pressure from 175.0 +/- 11 (mean +/- s.d.) mmHg to 158.7 +/- 6 mmHg (p less than 0.01), and of diastolic blood pressure from 113.5 +/- 8 mmHg to 102.7 +/- 5 mmHg (p less than 0.01). After 4 weeks with atenolol in association with half a tablet of Moduretic, systolic blood pressure further decreased to 145.7 +/- 8 mmHg (p less than 0.01), and diastolic blood pressure to 90.2 +/- 10 mmHg (p less than 0.01). Seven out of 20 patients remained with diastolic blood pressure greater than or equal to 95 mmHg despite the above combination therapy. In these patients, the doubling of diuretic dose (hydrochlorothiazide 50 mg + amiloride 5 mg) in combination with atenolol resulted in a further drop in systolic pressure (to 142.1 +/- 9 mmHg) and diastolic (to 92.1 +/- 6 mmHg) (both p less than 0.01). Plasma potassium concentration showed a slight and non-significant increase during atenolol monotherapy (from 4.4 +/- 0.5 mEq/l to 4.6 +/- 0.7 mEq/l; n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)