Effects of reduction in drugs or dosage after long-term control of systemic hypertension

The possibility of discontinuing--compared to reducing--antihypertensive drug treatment was investigated in 606 male hypertensive patients with entry diastolic blood pressure (BP) in the range of 90 to 114 mm Hg. Diastolic BP was controlled at less than 90 mm Hg with 1 of 4 regimens: low dose hydrochlorothiazide (HCTZ), 25 mg twice daily; high dose HCTZ, 50 mg twice daily; or high dose HCTZ plus a low or high dose of a step II drug (propranolol, clonidine or reserpine). After 6 months of treatment that controlled BP, dosages were reduced in two-thirds of the patients. In those patients receiving low dose HCTZ and randomized to dose reduction, antihypertensive drugs were completely discontinued. Although approximately half of these patients remained normotensive for the first 6 months, a significantly greater proportion had elevation of BP compared to the control group, which continued to receive treatment (p less than 0.0001). In the high dose HCTZ drug group, the proportion of patients remaining normotensive did not differ among those stepped down to low dose HCTZ and the fully treated control group. While not achieving significance the trend was similar with the step II regimens. Although some patients remained normotensive after discontinuation of step II drugs, a greater proportion returned to elevated BP than when step II dosage was unchanged. Therefore, while stopping therapy may be effective in some patients, a decreased dosage is significantly more effective as a method for maintaining an antihypertensive effect. Decreasing drug dosages offers the dual benefit of minimizing side effects and reducing drug costs.