- Antihypertensive
effects of ß-blockers are due to:
- Decreased myocardial
contractility and rate
- Consequences of decreased
renin secretion.
- Both effects occur as a
consequence of ß-adrenoceptor
blockade.
- Decreased renin levels lead
to decreases in circulating angiotensin
II and effects on aldosterone levels.
- Metoprolol
(Lopressor) inis an example of a cardio-selective
beta blocker, antagonizing mainly ß1
receptors.
- Cardioselective agents also,
however, have effects at beta-2 sites and may be
relatively contraindicated in certain clinical
conditions, such as asthma or chronic obstructive
pulmonary disease (COPD)
- ß receptor
blockade cause:
- decreases in myocardial
contractility
- increases in serum
triglycerides and decreases in HDL
cholesterol levels
- increases in bronchial
smooth muscle tone
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