Beta-blockers are used less commonly now that more effective treatments with less side effects are available.
The exact way in which they lower blood pressure is not fully understood but is thought to result from a combination of actions which:
- slow the heart rate to around 60 beats per minute
- reduce the force of contraction of the heart
- decrease the workload of the heart (cardiac output)
- change blood vessel dilation or constriction
- reduce sensitivity of blood pressure sensors (baroreceptors) in the larger arteries
- block stress hormone (adrenaline/epinephrine) receptors
- lower secretion of a kidney hormone, renin, which is involved in blood pressure regulation.
On average, a beta-blocker reduces systolic blood pressure (your upper reading) by 9.3 mmHg when used alone.
Although trials have found that their use is associated with a higher relative risk of stroke and new onset diabetes compared with the other blood pressure treatments, they still have a role to play in some patients. Beta blockers are sometimes used as a first line treatment in young people with hypertension and in people who have coronary heart disease as they reduce the work load of the heart. As a result, beta-blockers have been shown to significantly reduce the risk of having a second heart attack and may prolong life in high risk individuals.
Because they also affect receptors in the lungs, they should not be used in people with asthma as they may trigger an asthma attack.
Beta-blockers should not be withdrawn suddenly, but tailed off slowly so that rebound high blood pressure or angina does not result.
If your blood pressure is raised, self-monitoring is key to maintaining good control.
Click here for advice on choosing a blood pressure monitor to use at home.
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