In the first review to compare quarter-dose therapy to standard dose and placebo, researchers found that two medications in combination was just as effective as one standard dose of blood pressure-lowering medication. They also found that four medications in combination, each at a quarter dose, was nearly twice as effective as one standard dose.
The side effects from single and dual quarter-dose therapies were about the same as from placebo and much less than from a standard dose of a single antihypertensive medication, researchers said. There was little information on side effects for the quadruple quarter dose therapy.
“Widespread control of blood pressure is generally low, even in high-income countries,” said Anthony Rodgers, M.B.Ch.B., Ph.D., professor at The George Institute for Global Health, University of New South Wales in Sydney, Australia. “Because high blood pressure is so common and serious, even small improvements in management can have a large impact on public health.”
Each class of high blood pressure medications has different possible side effects, including weakness, dizziness, insomnia, headache and muscle cramps.
Researchers analyzed and compared results from 42 trials involving 20,284 people with high blood pressure on various doses of medications or taking no medication.
The review included many different types of medications from the five main classes of drugs to treat hypertension, including ACE inhibitors, angiotensin receptor blockers, beta blockers, calcium channel blocker and thiazides.
While low-dose combinations for blood pressure control is promising, there still isn’t enough research to warrant a change in how doctors prescribe blood pressure-lowering therapies and only a few low dose combinations are available, researchers said.
“This new approach to treatment needs more research before it can be recommended more widely,” Rodgers said. “The findings have not yet been tested in large long-term trials. People should not reduce the doses of their current medications.”
The study is published in the American Heart Association journal Hypertension.