Anti-hypertensive ( beta-blocker )
Drugs:
1) beta blocker:
Acebutolol
Betaxolol
Bisoprolol
Carvedilol
Esmolol
Labetalol
Penbutolol
Timolol
2) selective beta 1 blocker:
Metoprolol
Atenolol
Nebivolol
3) Non-selective beta 1 and beta 2 blocker:
Pindolol
Nadolol
Mechanism of action:
1) beta adrenoceptors on kidney: When inhibiting beta in the kidneys, renin is reduced and thus prevents the conversion of angiotensinogen to angiotensin I, and thus the enzyme Angiotensin convert (ACEi) decreases, which inhibits the conversion of angiotensin I to angiotensin II, this leads to a decrease in the retenntion of both water and sodium, thus reducing blood volume, which in turn It reduces cardiac output and reduces blood pressure.
2) beta adrenoceptors on heart: When beta is inhibited in the heart, this leads to a decrease in cardiac output, thus reducing blood pressure in the body.
Used in hypertensive patients with:
Heart disease ( such as supraventricular )
Myocardial infarction
Angina pectoris
Heart failure
Side effect:
Bradycardia
Hypotension
Fatigue
Lethargy
Insomnia
Depression
Erectile dysfunction
Drug interactions:
The use of propranolol with hydralazine is contraindicated because hydralazine inhibits the metabolism of propranolol and thus leads to an increase in the concentration of propranolol in the body, so it is necessary to reduce the dose of one or both of these drugs.
Precautions:
1) asthma: not use non-selective beta blocker drugs with asthma patients because these drugs lead to bronchoconstriction.
2) angina: not use non-selective beta blocker drugs with angina patients because these drugs lead to bronchoconstriction, so we use selective beta 1 blocker
1- Abrupt withdrawal may induce angina, myocardial infarction, and even sudden death in patients with ischemic heart disease. Therefore, these drugs must be withdraw over a few weeks in patients with hypertension and ischemic heart disease.
2- Decrease libido and cause erectile dysfunction Non-selective B-blockers may disturb lipid metabolism, decreasing high-density lipoprotein cholesterol and increasing triglycerides.