Receptor blockers are commonly used cardiovascular drugs, which are widely used in patients with hypertension, coronary heart disease and heart failure. These drugs are often called [XX prolol], such as propranolol, metoprolol, bisoprolol, aroprolol, carvedilol, etc.
Why can receptor blockers lower blood pressure? This starts with the receptor.
There are three types of adrenergic receptors:
1 Receptors are mainly distributed in myocardium, which can excite and cause increased heart rate and myocardial contractility.
Receptors exist in bronchus and vascular smooth muscle, which can excite and cause bronchiectasis, vascular relaxation, visceral smooth muscle relaxation, etc.
3 receptors mainly exist in adipocytes and can stimulate and cause lipodecomposition.
Receptor blockers commonly used clinically, according to the characteristics of drugs, can block the effects of one or more receptors, weaken cardiac contraction and slow down heart rate to reduce blood pressure.
We compare the heart to a water pump and blood pressure to a water pipe. The pressure of the water flowing in the water pipe on the pipe is blood pressure. If the power of the water pump is too high, the pressure on the water pipe will be greater. At this time, reducing the power of the water pump will reduce the pressure, and the same is true for blood pressure.
Applicable population
Among several kinds of antihypertensive drugs, the antihypertensive effect of receptor blockers is relatively weak, which can increase the perioperative cardiovascular adverse events and death risks of patients with simple hypertension. Therefore, receptor blockers are not preferred for patients with simple hypertension.
However, receptor blockers are still the first-line recommended antihypertensive drugs for patients with coronary heart disease, heart failure and high heart rate. The recommended population mainly includes the following categories:
Hyperkinetic hypertension
Especially in young hypertensive patients, it is common: the cardiac output per stroke increases and the peripheral vascular resistance increases mainly due to fast heart rate and enhanced myocardial contractility, which is mainly manifested by diastolic hypertension and decrease of pulse pressure (difference between systolic pressure and diastolic pressure).
For such patients, receptor blockers are the most effective antihypertensive drugs, which can also effectively control heart rate and relieve discomfort symptoms such as palpitation.
Hypertensive patients with fast heart rate, coronary heart disease and heart failure
In these people, the use of receptor blockers can reduce the oxygen consumption of the heart and play a role in protecting the heart.
Side Effects and Precautions
As mentioned earlier, receptors are divided into several types, and different receptors have different effects. The side effects of receptor blockers as drugs are also related to different types of receptors, mostly due to receptor 2 and receptor 3 block.
Abnormal glycolipid metabolism
It is generally believed that the incidence of hypoglycemia caused by receptor blockers is very low, but in diabetic patients with hypoglycemia after insulin application, the application of receptor blockers can delay the recovery of hypoglycemia or cover up hypoglycemia reaction due to slow heart rate after taking drugs.
For some receptor blockers, it can also increase triglyceride and low density lipoprotein in blood and reduce high density lipoprotein, which generally has no effect on total cholesterol.
Although it has an impact on glycolipid metabolism, receptor blockers are very important drugs for coronary heart disease patients with blood sugar and blood lipid abnormalities. When applied,
Attention should be paid to monitoring the level of blood sugar and lipid, which can minimize its adverse effects on glucose and lipid metabolism.
May cause erectile dysfunction
In men, long-term use of large doses may cause erectile dysfunction. If there is any influence, you can consult your doctor and change to other types of antihypertensive drugs.
If the patient’s condition is especially suitable for treatment with receptor blockers, another receptor blocker can be considered.
Causing an asthma attack
For hypertensive patients with asthma, try not to choose receptor blockers to reduce blood pressure.
Precautions
It is suggested that patients follow the advice of cardiologists and select appropriate receptor blockers according to their own conditions.
- Propranolol, a non-selective receptor blocker, is the best choice for hyperthyroidism patients with hypertension. Hypertensive patients complicated with chronic obstructive pulmonary disease, if accompanied by discomfort such as fast heart rate and palpitation, are suitable to select highly selective receptor blockers with receptor blocking effect, such as bisoprolol; For patients with heart failure accompanied by hypertension, carvedilol, which has the blocking effect of receptor 1, is the best choice for lowering blood pressure.
Is what selective?
There are three types of receptors, and according to the types of receptors that drugs can produce effects, they can be divided into
Non-selective receptor blockers, the representative drug of which is propranolol; Selective 1 receptor blockers, representing bisoprolol and metoprolol, are commonly used blockers in clinical practice. Receptor blockers with peripheral vasodilation function, such as carvedilol, aroselol, labetalol and nebiprolol.
The more selective the drug is, the fewer types of receptors it acts on, and the less side effects the drug has.
Start with small doses and monitor heart rate
The first use should start with a small dose, gradually increase the dose, and adjust the dose according to the pulse rate. The pulse rate can be measured before waking up in the morning, and the resting pulse rate can be controlled to be 60-70 times/min, not less than 55 times/min.
Attention should be paid to avoid hypotension and bradycardia due to excessive dose.
Avoid sudden withdrawal of drugs
Patients who have been using receptor blockers for a long time may suffer from anxiety, palpitations or gastrointestinal reactions within 1-2 days after sudden withdrawal. Severe cases may suffer from elevated blood pressure, tachycardia, aggravation of angina pectoris and even myocardial infarction.
This has something to do with the characteristics of the drug. If the drug needs to be stopped, it should be gradually reduced, usually taking 2 weeks.