1 How to choose antihypertensive drugs
At present, antihypertensive drugs used clinically are roughly divided into six categories, and a new category of drugs has been invented in almost 10 years. . According to the time on the market, antihypertensive drugs are divided into:
1. Alpha-receptor blockers
Launched in the 1940s, the representative drug is terazosin. By blocking adrenergic alpha receptors, it directly dilates blood vessels and lowers blood pressure. The antihypertensive effect is relatively strong, but the drop in blood pressure reflexively causes the heart rate to increase, which may induce angina in some patients. The biggest side effect is orthostatic hypotension (low blood pressure or even collapse when the body changes when lying or squatting or suddenly standing up). Because of its severe side effects, it is not used clinically as a first-line antihypertensive drug and is rarely used. However, it can also be used for refractory hypertension such as renal hypertension.
2. Diuretics
Launched in the 1950s, the representative drug hydrochlorothiazide. Diuretics are roughly divided into 4 types:
1. Thiazides: the representative drug is hydrochlorothiazide;
2. Loop diuretics: furosemide, torsemide, etc.;
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3. Aldosterone antagonist: also called potassium-sparing diuretic, the representative drug is spironolactone;
4. Osmotic diuretic: mannitol.
Excessive sodium intake is a major cause of high blood pressure, and too much sodium in the body inhibits the effectiveness of some antihypertensive drugs. Diuretics are used to treat high blood pressure not for urination, but for sodium excretion. Diuretics are the basis of antihypertensive treatment and can be used in conjunction with almost any other antihypertensive drug.
1. Hydrochlorothiazide has a slow diuretic effect, but its sodium excretion effect is not bad, so it is the first choice drug for antihypertensive diuretics. The dosage of hydrochlorothiazide is 12.5 mg to 25 mg (half a tablet to 1 tablet) per day. If the dosage is increased, the antihypertensive effect will not increase, but the risk of hypokalemia will increase. Some ARB antihypertensive drugs, such as irbesartan hydrochlorothiazide tablets, valsartan hydrochlorothiazide tablets, etc., add 12.5mg hydrochlorothiazide tablets during preparation to increase the antihypertensive effect.
2. The second type of loop diuretic has a very strong diuretic effect and is used for diuretic treatment of severe edema, heart failure, etc. It often causes hypokalemia, so it is generally not used for antihypertensive treatment.
3. The third diuretic, spironolactone, also has a relatively slow diuretic effect and is a specific treatment drug for secondary hypertension caused by hyperaldosteronism. Because it reduces potassium excretion, it can offset the hypokalemia caused by other diuretics. It is often used in combination with thiazide diuretics, which can not only increase the diuretic effect but also avoid serum potassium disorders. Long-term use alone may cause hyperkalemia. Note: Spironolactone can cause feminizing tendencies such as gynecomastia, so young male patients with hypertension should use it with caution.
4. The fourth osmotic diuretic cannot be used for antihypertensive treatment.
5. In addition, indapamide tablets are also a diuretic, which lowers blood pressure by excreting sodium and relieving vasospasm.
Note: Diuretics can interfere with the excretion of uric acid and thus can induce gout attacks.
3. Beta blockers
Launched in the 1960s, the representative drug is metoprolol. Adrenergic receptors are divided into 3 types, namely β1 receptors, β2 receptors and β3 receptors. β1 receptors are mainly distributed in the myocardium, and stimulation can cause increased heart rate and myocardial contractility; β2 receptors are distributed in bronchial tubes, and stimulation can cause bronchiectasis; β3 receptors are mainly distributed on fat cells, and stimulation can cause lipolysis. Beta-blockers block the above-mentioned effects and cause effects opposite to excitement, such as slowed heart rate, decreased myocardial contractility, bronchospasm, etc.
Beta-blockers are currently divided into three generations:
1. The first generation is a non-selective beta-blocker.
This type of drug indiscriminately blocks three receptors, which not only causes the heart rate to slow down and blood pressure to drop, but also causes bronchospasm, induces asthma, and interferes with glucose metabolism, causing blood sugar to rise. The ability to lower blood pressure is not strong, but there are many side effects, so this type of drug has basically been eliminated.
2. The second generation selectively blocks β1 receptors. The representative drug is metoprolol. Others include atenolol, bisoprolol, etc. It can lower blood pressure, slow down the heart rate, and has no effect on the trachea and blood sugar. It is currently the main force of β-receptor blockers and can be given priority.
3. The third generation is also a non-selective β-receptor blocker, but with the addition of α-receptor blocker, it antagonizes the side effects of the first generation drug and has a more effective antihypertensive effect. Well, it’s a rising star in the class of beta-blockers. Representative drugs are arollol, carvedilol, etc.
Beta-blockers have an additional protective effect on the heart and can be used first in patients with high blood pressure, mainly high diastolic blood pressure (low blood pressure). In addition, priority can be given to hypertension caused by anxiety disorders and hypertension where mental factors play a major role.
The absolute contraindication to β-blockers is atrioventricular block of degree II or above.
4. Calcium channel blockers
Launched in the 1970s, they are also called calcium antagonists. Since the names of these drugs have the word "diping" in them, they are commonly known as diping. class, representing the drug amlodipine.
By blocking calcium ion channels on the smooth muscle cell membranes of myocardium and blood vessel walls, it directly dilates blood vessels and lowers blood pressure.
CCB is a big family with many members, each with different “gender, age, personality”, etc. To sum up, they are currently divided into three generations: old and young.
First generation: representative drug nifedipine. This type of medicine has a quick onset of action and a short maintenance time, and needs to be taken three times a day. Blood pressure decreases quickly after taking it, but due to the rapid expansion of blood vessels, patients often feel headache, dizziness, flushed face and ears, and accelerated heartbeat. Because nifedipine has the characteristics of quick onset and quick failure, it is difficult to stabilize blood pressure even if it is taken three times a day. Moreover, long-term use of nifedipine alone to reduce blood pressure can easily cause sudden death. Therefore, nifedipine has been banned from long-term antihypertensive use. It is now mostly used for temporary lowering of malignant hypertension and particularly high blood pressure, but it is now considered unsafe even in this case, so try to avoid using it.
Second generation: In order to overcome the shortcomings of nifedipine, some pharmaceutical companies put nifedipine in a special coat to extend the release time of the drug, extend the duration of action, and reduce side effects. Purpose. This is the second generation of drugs, including nifedipine controlled-release tablets and nifedipine extended-release tablets. Take 1 to 2 times a day. The side effects of sudden death are gone, but side effects such as flushed face and ears still exist. Long-term use may also cause gum hyperplasia and mild edema of the lower limbs. These medicines should not be taken in half.
The third generation: the representative drug amlodipine, with a half-life of 35 to 50 hours, is the longest-lasting antihypertensive drug among all current antihypertensive drugs. Therefore, there is no need for sustained release or controlled release. It can be taken once a day and blood pressure can be controlled stably for 24 hours. Its absorption and efficacy are not affected by the patient's gastrointestinal function and food. It can also be taken with most drugs or broken in half. In addition, because its effect lasts so long, patients who occasionally miss a dose will not cause an increase in blood pressure. Therefore, it is the most commonly used CCB and one of the most commonly used antihypertensive drugs.
5. Angiotensin-converting enzyme inhibitors
Launched in the 1980s. Since the name of this type of medicine has the word "Pluli" in it, it is commonly known as the Puli type. The representative drugs are benazepril, fosinopril, and others include captopril, enalapril, lisinapril, and lisinopril. Nopril, Ramipril, Perindopril, etc.
Angiotensin II is a substance that strongly constricts blood vessels and is one of the "protagonists" in causing hypertension. ACEIs lower blood pressure by inhibiting the production of angiotensin II.
In addition, ACEI can also dilate the efferent arterioles of the glomerulus and inhibit angiotensin II in renal tissue. Therefore, in addition to lowering blood pressure, ACEI has two other independent effects: lowering urinary protein and delaying renal function. damage (kidney preservation). Because of these two effects, ACEIs are the drug of choice for hypertension in patients with kidney disease and diabetes.
The side effects of ACEI include dry cough, increased blood potassium, increased blood creatinine and other side effects. The incidence of dry cough is particularly high in East Asians, and some people often have to stop taking medications because of dry cough. This is also the reason why this type of drug was very popular when it was first launched, but then gradually fell into disfavor. The incidence of elevated serum potassium and elevated serum creatinine is not high, but it is more dangerous once it occurs, so it attracts more attention.
6. Angiotensin receptor blockers
Launched in the 1990s. Since the name of this type of medicine has the word "sartan" in it, it is commonly known as Sartan. The representative medicines are valsartan, candesartan, irbesartan, and others include losartan and telmisart. Tan, olmesartan, etc.
This type of drug is the latest antihypertensive drug currently on the market, and it can be said that all of them are high-quality products.
It also targets angiotensin II, so the hypertension guidelines compare the two, so you can choose either one when using it. However, the difference between the two is that ACEI inhibits the production of angiotensin II, while ARB blocks the action of angiotensin II to lower blood pressure.
Like ACEI, ARB also has three major functions: lowering blood pressure, lowering urinary protein, and protecting kidneys. The indications are also the same as ACEI, but ARB is much safer than ACEI. It does not have the side effects of dry cough and blood potassium. The side effects of elevated blood creatinine are also much milder. Therefore, it is reasonable for ARB to gradually replace ACEI.
Initially, it was believed that ACEIs cannot be used when serum creatinine is >265 umol/L, and ARBs cannot be used when serum creatinine is >350 umol/L. Some people even mistakenly believe that these two types of drugs cannot be used as long as serum creatinine is elevated. . This is also the reason why the community doctor at the beginning of the story asked the patient to stop taking candesartan. Later, a large amount of data confirmed that these worries were unnecessary. Serum creatinine is no longer a contraindication, but changes in serum creatinine should be monitored. If the serum creatinine rises above 30 during use, the dose should be reduced. If the serum creatinine rises above 50, the drug should be discontinued.
In other situations, such as serum potassium greater than 5.5 mmol/L, pregnant women, or bilateral renal artery stenosis, ACEI and ARB cannot be used.
In addition, ACEI and ARB cannot be used together.