Analysis of the advantages and applicable populations of beta-blockers in the treatment of hypertension

What are the advantages and adverse reactions of beta-blockers?

Beta-blockers (especially lipid-soluble beta-blockers) can improve long-term clinical outcomes in patients with hypertension, including reducing mortality, stroke, and the incidence of heart failure. Based on extensive evidence-based medicine regarding the treatment of hypertension with beta-blockers over many years, both domestic and international hypertension treatment guidelines recommend beta-blockers as effective drugs for treating hypertension.

(1) Situations where beta-blockers are the first choice: Because beta-blockers inhibit sympathetic nerve excitation, they have irreplaceable advantages in the following areas and should be the first choice:

① Tachyarrhythmias (such as sinus tachycardia, atrial fibrillation);

② Coronary artery disease (stable/unstable angina, post-myocardial infarction);

③ Patients with heart failure and hypertension;

④ Patients with increased sympathetic nerve activity (early-onset hypertension with increased heart rate, those under social and psychological stress, those with increased mental stress such as anxiety, perioperative hypertension, those in high-circulation states such as hyperthyroidism, those living at high altitudes, etc.);

⑤ Young hypertensive patients who are contraindicated or cannot tolerate ACEIs/ARBs.

(2) Precautions for the use of beta-blockers:

① Selective beta-blockers and beta-blockers with α-receptor blocking effects have relatively small effects on glucose and lipid metabolism and peripheral blood vessels, and should be given priority. Traditional non-selective beta-blockers, such as propranolol, have adverse effects on glucose and lipid metabolism.

② In hypertensive patients without heart failure or myocardial infarction, the single use of high-dose beta-blockers combined with thiazide diuretics should be avoided to reduce the possibility of causing glucose and lipid metabolism disorders.

③ The combination of beta-blockers with long-acting dihydropyridine calcium channel blockers (CCBs) or alpha-blockers can achieve a synergistic antihypertensive effect, inhibiting the reflex sympathetic nerve excitation induced by CCBs or alpha-blockers, and better protecting target organs.

④ The combination of beta-blockers with ACEIs or ARBs is currently the standard treatment recommended for hypertension complicated by coronary artery disease or heart failure. The beneficial effects of ACEIs or ARBs on glucose metabolism may offset the potential adverse effects of beta-blockers on glucose metabolism.

⑤ For patients with metabolic syndrome and predisposition to diabetes, but without heart failure, myocardial infarction, or rapid arrhythmias (such as sinus tachycardia or atrial fibrillation), and for elderly patients over 60 years of age, beta-blockers are not recommended as initial treatment.

(3) Contraindications for beta-blockers: Because beta-blockers primarily work by inhibiting the sympathetic nervous system, they also have a certain inhibitory effect on the heart. Therefore, they should be avoided in cases of severely impaired cardiac function, such as second- or third-degree atrioventricular block, severe heart failure, or bradycardia (heart rate <55 bpm).

Furthermore, beta receptors are also distributed in bronchial smooth muscle, and their blockade results in bronchoconstriction. Therefore, patients with bronchial asthma or chronic obstructive pulmonary disease should not use them; drugs without receptor selectivity, such as propranolol, are more likely to cause this.

(4) Relative contraindications of beta-blockers: Beta receptors are widely distributed in peripheral blood vessels. In some individuals, blocking beta receptors in the limbs results in vasoconstriction. Therefore, patients with vascular disease in the limbs should not use the medication if their limbs become cold after administration. Because beta-blockers have sedative and anti-anxiety effects, they are also unsuitable for athletes engaged in competitive sports.

(5) Potential adverse reactions of beta-blockers:

① Because beta-blockers primarily block the sympathetic nervous system, the result is a slowing of heart rate and conduction. The higher the sympathetic nerve excitability, the better the effect; therefore, serious adverse reactions are rare. However, in patients with impaired sinoatrial node function and atrioventricular conduction, they can worsen bradycardia and conduction block, making their use in such cases unsuitable.

② Another important point to note regarding long-term use of beta-blockers is withdrawal reaction. Sudden discontinuation of the medication can worsen angina. Therefore, patients with coronary artery disease should avoid sudden discontinuation of the medication. ③ These drugs may affect blood glucose and lipid metabolism, especially non-selective beta-blockers such as propranolol. Highly selective beta-blockers such as bisoprolol and drugs containing alpha-blockers do not cause metabolic disturbances.

④ Bronchial and pulmonary adverse reactions: Inducing or aggravating bronchial asthma is more likely with selective beta-blockers.

⑤ Central nervous system reactions: Highly lipid-soluble beta-blockers such as propranolol and metoprolol easily cross the blood-brain barrier, showing better effects in anti-anxiety, anti-tremor, and migraine prevention. They are also more likely to cause headaches, fatigue, and vivid dreams.

⑥ The incidence of sexual dysfunction is less than 5%.