A total of 80-90 per cent of people over the age of 60 have some form of high blood pressure. By 2015, there will be one million people with hypertension on the island of Ireland. Three out of every four people in a certain age group will be hypertensive.
New medications — dual combination therapy — cut down the number of times that a GP has to see individual patients; hopefully facilitating treatment of others with the condition. This should lead to blood pressure reductions over a larger population, with resultant reduction in stroke and dementia, the two biggest factors in health costs.
“GPs need tools that have an impact, but will not require weekly attendance in the surgery to measure blood pressure and alter doses,” said Dr Eamon Dolan, consultant stroke physician at Connolly Hospital.
Of all the angiotensin-converting enzyme (ACE) inhibitors, perindopril probably has the most outcome data. The ASCOT trial considered amlodipine plus perindopril and there have been studies of the compound over the years. The PROGRESS study examined perindopril in combination with indapamide. “We use it quite a lot, due to the evidence base,” said Dr Dolan.
A number of outcome studies, including EUROPA, were carried out in various categories and have stood the test of time, in Dr Dolan’s view. Different preparations — longer-acting versions — are becoming available. “It is a good product. We invariably put people on perindopril post-stroke, in recognition of that,” said Dr Dolan.
The usage of angiotensin receptor blockers (ARBs) is increasing and there are a higher number of them. These agents reduce the pressure against which the heart must pump. They prevent the conversion of angiotensin I to angiotensin II. That has positive effects on blood volume and arterial constriction, reducing the amount of work the heart has to do. “They deliver long-lasting control. Duration of action, in addition to their potency, is a key advantage,” said Dr Dolan. ARBs can be taken at any stage during the daytime period and good 24-hour control can be expected.
Many manufacturers offer combination therapies. There are a number of advantages to ‘flexipills’, which allow medications that confer contrasting benefits to be taken in one pill. The most commonly-used combination now is an ARB plus a calcium antagonist — usually amlodipine.
For blood pressure reduction purposes, there is good evidence that where an ARB is prescribed (half maximum dose of telmisartan, for example), a second drug should be prescribed (such as amlodipine) rather than increasing the ARB to its maximum dose. The drugs have complementary actions.
Evidence indicates you do not get as much impact going up from 20mg to 40mg of olmesartan than you would starting with 20mg of olmesartan and adding in 5mg of amlodipine.
There is good evidence that amlodipine has a positive effect on median blood pressure variability. “It seems to be very beneficial in ‘smoothing out’ blood pressure,” Dr Dolan said.
“In combination with an ARB, a very potent 24-hour blood pressure medication, that may be a winning combination. We used to tinker around with blood pressure. Now we can introduce these medications earlier, to much better effect. More and more, this is used as a first-line medication. These are safe, well tolerated, efficacious medications.”
Diuretics are very effective. There has traditionally been a symbiotic relationship between diuretics and ACE inhibitors and, to some extent, this is true with ARBs also. They act on different mechanisms and can have a combined beneficial effect. There has always been good evidence for indapamide for treatment of stroke.
There is undoubtedly, though, another group of patients in whom medications need to be increased beyond dual therapy. There are other medications available — including direct renin inhibitors such as aliskiren. “They give good blood pressure control and are a welcome addition,” said Dr Dolan.
Beta blockers are also used.