Strategies for the control of high blood pressure in the UK may be updated after researchers found that starting therapy with a combination of two drugs was more effective than one medicine alone.
The randomised, controlled trial, carried out by researchers from the Universities of Glasgow and Cambridge, the British Hypertension Society and Swiss drug giant Novartis and published in The Lancet, found that a combination of Novartis' Rasilez (aliskiren; sold as Tekturna in the US) and amlodipine induced a faster and higher cut in blood pressure than either drug administered alone.
Both drugs have very different modes of action to lower blood pressure. Rasilez is a first-in-class product that driectly inhibits the enzyme renin to tackle high blood pressure at its source, which ultimately reduces the contraction of the arterial smooth muscle responsible for vasoconstriction and increased blood pressure. Amlodipine is a long-acting calcium channel blocker that works by relaxing the smooth muscle in the arterial wall to reduce pressure.
In the trial, patients who were initiated on a combination of these two drugs were found to have a 6.5mmHg greater reduction in average systolic blood pressure than those given only one of them. By week 24, by which point all patients were taking the combo of Rasilez and amlodipine, the magnitude of this difference had decreased to 1.4mmHg, though it was still of significance.
In addition, the safety of both treatment regimens were found to be similar, with 14% of patients taking the combination from the start, 14% of those starting on Rasilez and 18% of those initially on amlodipine discontinuing the trial due to side effects.
Standard practice in the UK currently involves starting patients on one of these drugs and subsequently switching to combination therapy if necessary. However, the study authors suggest that clinical practice should be updated so that patients are immediately given the combination therapy, given that the results indicate this is more effective and just as safe.
Commenting on the study, Professor Jeremy Pearson, associate medical director at the British Heart Foundation, said it "adds significantly to the evidence that starting treatment for patients with high blood pressure with two medicines rather than one is safe, and more effective than waiting to add the second medicine later".
He also noted that adequate control of blood pressure "is still hard to achieve in many patients", and that consequently the BHF is funding follow-up trials to this research to help determine "the best way to treat patients whose hypertension is still poorly controlled with two drugs, and who need extra medicines”.
According to the High Blood Pressure Foundation, hypertension - one of the most important risk factors for heart attacks and stroke - is a silent killer that affects one in three hearts in the UK, highlighting the urgent need for more effective treatment strategies and medicines to combat the condition.