Efficacy of potassium and magnesium in essential hypertension: a double-blind, placebo controlled, crossover study.

OBJECTIVE

To evaluate the antihypertensive activity of potassium given alone or in combination with magnesium in patients with mild hypertension.

DESIGN

A double blind, randomised, placebo controlled, crossover trial of 32 weeks' duration.

SETTINGS

Cardiology outpatient department, Sassoon General Hospitals, Pune, India.

PATIENTS

37 Adults with mild hypertension (diastolic blood pressure less than 110 mm Hg).

INTERVENTION

Patients received either placebo or potassium 60 mmol/day alone or in combination with magnesium 20 mmol/day in a crossover design. No other drug treatment was allowed.

MEASUREMENTS

Blood pressure and heart rate assessed at weekly intervals and biochemical parameters at monthly intervals.

RESULTS

Potassium alone or in combination with magnesium produced a significant reduction in systolic and diastolic blood pressures (p less than 0.001) and a significant reduction in serum cholesterol concentration (p less than 0.05); other biochemical variables did not change. Magnesium did not have an additional effect. Urinary potassium excretion increased significantly in the groups who received potassium alone or in combination with magnesium. The drug was well tolerated and compliance was satisfactory.

CONCLUSION

Potassium 60 mmol/day lowers arterial blood pressure in patients with mild hypertension. Giving magnesium as well has no added advantage.