A drug that costs £1.50 a month and has been around for 50 years could revolutionise the care of patients with persistent high blood pressure.
Spironolactone was first used in 1959 as a water pill to treat fluid retention – but new findings show it also works in three out of five patients whose blood pressure is out of control.
Experts today said the finding offered hope of ‘spectacular’ cost savings.
An estimated 500,000 people have high blood pressure that does not respond to at least three types of medication, known as resistant hypertension.
People with high blood pressure are advised to change their lifestyle and eat less salt, lose weight, drink less alcohol, eat more fruit and vegetables and exercise more.
But six million Britons also take drugs to reduce their blood pressure, which raises the risk of early death, heart attacks and strokes.
The new study involved 335 patients who had uncontrolled blood pressure despite treatment with the maximum doses of three antihypertensive medicines.
The results show that 60 per cent of patients had their blood pressure controlled for the first time.
Spironolactone was three times more likely to work, when added to three existing pills, than two other types of drug added to the mix.
Findings from the study, funded by the British Heart Foundation charity, were released at the European Society of Cardiology Congress in London.
Study presenter Professor Bryan Williams, from University College London, said: ‘Spironolactone is overwhelmingly the most effective treatment for resistant hypertension.
‘When we look at the achieved blood pressure on these treatment options, the average home systolic blood pressure on spironolactone was 134.9 mm Hg, which is just below the target level of 135 mm Hg.
‘In other words, we were controlling a large percentage of these patients previously defined as [having] uncontrollable hypertension.’
The drug costs the NHS between £1.50 and £2.50 a month, depending on the dose.
Professor Williams said the drug offers a ‘spectacularly cost-effective approach’ in the UK and elsewhere, because it’s cheap and patients are at very high risk of suffering serious heart problems.
‘These people are at an especially high risk of cardiovascular events due to their long-term exposure to high blood pressure and the fact that many of them have other conditions such as diabetes and chronic kidney disease,’ he added.
He added that despite 50 years of research, there had been little progress in achieving the optimal drug treatment for resistant hypertension – but the ‘unequivocal’ trial findings should now lead to a re-writing of current guidelines and clinical practice.
Spironolactone, originally developed as a diuretic, to treat people who retain too much fluid, is currently used for heart failure and some liver and kidney conditions.
In the trial there were larger reductions in blood pressure for patients taking the drug in combination with three other medications, than for those trying two other drugs or a dummy pill.
Patients had their blood pressure measured at six and 12 weeks.
Professor Peter Weissberg, medical director of the British Heart Foundation, said it showed that inexpensive drugs which have been around for a long time are effective and safe for treating high blood pressure.
Because doctors are already familiar with the drug, he said, the findings ‘should lead rapidly’ to its everyday use in resistant hypertension and for hypertensive patients who may be at high risk of developing diabetes.
He said: ‘The results are hugely encouraging both for patient welfare and the NHS budget. We would expect medical guidelines across the world to change rapidly to reflect these results.’