Читать книгу High Blood Pressure: Natural Self-help for Hypertension, including 60 recipes - Michelle Berriedale-Johnson - Страница 33

The way beta-blockers lower blood pressure is not fully understood but is thought to result from a combination of actions in which they:

alter the way nerve signals cause some blood vessels to dilate or constrict

slow the heart rate to around 60 beats per minute

reduce the force of contraction of the heart

decrease the workload of the heart and cardiac output

lower secretion of a kidney hormone, renin

reduce sensitivity of blood pressure sensors (baroreceptors)

block stress hormone (adrenaline) receptors

have some effects on the brain.

In general, beta-blockers are used as a first-line treatment in young people with hypertension and in people who have coronary heart disease. 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 have been shown to significantly reduce the risk of having a second heart attack and may prolong life in high-risk individuals.

Beta-blockers should not be withdrawn suddenly, but must be tailed off slowly so that rebound high blood pressure (or angina) does not occur.