Special Planning: High Blood Pressure 365 Questions
Yimaitong works with clinicians from various disciplines to answer the "100,000 whys" of disease diagnosis and treatment, and provide medical guidance for patients and their families.
The author of this issue is Dr. Li Ling
Deputy Director of the Department of Hypertension, Doctor of Medicine, Chief Physician of Henan Provincial People's Hospital
Highlights of this issue
1. Diuretics
2. Renin angiotensin-aldosterone system (RAAS) inhibitors
3. Calcium channel blockers (CCBs)
4. Adrenergic receptor blockers
▍Introduction
In the outpatient clinic, many patients with high blood pressure are very resistant to taking antihypertensive drugs, and they are always worried about whether the drug is addictive and cannot be stopped or whether the drug has side effects.
Antihypertensive drugs exert a hypotensive effect by acting on one or more parts of the blood pressure regulating system, and can be pharmacologically classified according to the different sites of action of the drugs
1. Diuretics
The renal tubules are an important part of the action of diuretics, which can be divided into the following 4 categories according to the different sites of action of drugs:
Thiazide diuretics
It mainly inhibits the Na+-Cl- co-transport carrier of the distal convoluted tubule, affects the dilution process of urine, and produces a moderately strong diuretic effect. According to the molecular structure, it can be divided into thiazide-type diuretics (such as hydrochlorothiazide and benzylfluthiazide) and thiazide-like diuretics (such as indapamide, chlorthalidone).
Loop diuretics: selectively block the Na+-K+-2Cl- co-transport carriers in the thick segment of the ascending branch of the medullary loop, inhibit the concentrating process of urine by the kidney, and produce a strong diuretic effect. Commonly used clinical drugs include furosemide, bumetanide, and torsemide.
Potassium-sparing diuretics: spironolactone indirectly inhibits the K+-Na+ exchange of sodium channels at the distal end of the distal convoluted tubule and the collecting duct segment by antagonizing aldosterone, excreting sodium and potassium and producing inefficient diuretic effect, while triamterene directly inhibits the sodium channel in this segment and produces diuretic effect. Amiloride inhibits the H+-Na+ exchange in this segment and excretes Na+.
2. Renin angiotensin-aldosterone system (RAAS) inhibitors
RAAS inhibitors mainly include angiotensin-converting enzyme inhibitors (ACE inhibitors), angiotensin receptor blockers (ARBs), angiotensin receptor neprilysin inhibitors (ARNIs) and renin inhibitors.
ACE inhibitors reduce circulating angiotensin (Ang) II levels and eliminate their direct vasoconstrictors, and their antihypertensive effects may also be related to inhibition of bradykinin degradation and promotion of Ang1-7 production. Common drugs are captopril, perindopril, etc.
ARB blocks the binding of AngII., which is involved in the production of angiotensin-converting enzyme (ACE) and other bypass pathways, to AngI. type receptors and exert antihypertensive effects. Common drugs are valsartan, irbesartan, etc.
ARNI is a novel drug that acts on both RAAS and the natriuretic peptide system (NPs) to achieve multi-pathway antihypertensive by enhancing the blood pressure regulation effect of NPs while inhibiting RAAS. For example, sacubitril-valsartan shows superior protective effect on target organs such as the heart, kidneys and blood vessels.
Renin inhibitors can inhibit angiotensinogen decomposition to produce AngI., and the antihypertensive effect is not superior to ACE inhibitors and ARBs, and their application is limited. Direct renin inhibitors exert antihypertensive effects by inhibiting the activity of renin, but they are not currently available in mainland China.
3. Calcium channel blockers (CCBs)
According to the affinity classification with blood vessels and heart: according to the affinity and action ratio of CCB with arterial blood vessels and heart, it is divided into dihydropyridine CCB and non-dihydropyridine CCB, dihydropyridine CCB (various horizons) mainly act on arteries, and non-dihydropyridine CCBs - phenylamines (such as verapamil) and phenylthiazines (such as diltiazem) have poor vascular selectivity, and have negative time, negative conduction and negative force changes on the heart.
Classification according to affinity with calcium channel subtypes: CCBs are classified into L-type (e.g., nifedipine), L/N-type or L/T type (dual-channel, e.g., cinidipine, manidipine), and L/N/T type (three-channel) CCBs (e.g., Benidipine) according to their affinity with calcium channel subtypes.
4. Adrenergic receptor blockers
β receptor blockers
By selectively binding to β receptors, it produces a variety of antihypertensive effects, such as reducing cardiac output, reducing renin release, and central sympathetic impulses.
According to the relative selectivity of β1 receptors, β receptor blockers can be divided into: non-selective β receptor blockers (representative drugs are propranolol), selective β1 receptor blockers (representative drugs are bisoprolol, metoprolol and atenolol), which are commonly used in clinical practice β receptor blockers and non-selective blockers that act on β and α1 receptors (representative drugs: arolol, carvedilol, labetalol, etc.).
Alpha-1 blockers
These drugs selectively block blood circulation or catecholamines released by the central nervous system to bind to postsynaptic alpha-1 receptors and produce a hypotensive effect by dilating blood vessels. At present, the commonly used clinical α blockers mainly act on the periphery, including terazosin, prazosin, doxazosin, urapidil, etc.
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▍Summary
For example, diuretics and calcium ion antagonists are more suitable for patients with high systolic blood pressure and salt-sensitive hypertension, RAAS inhibitors are preferred for patients with diabetes and hypertension, and β receptor blockers are more effective for hypertensive patients with fast heart rate.
So when it comes to what antihypertensive drugs each patient takes, you still have to follow the advice of your specialist. Of course, in addition to the suitable population, each type of antihypertensive drug will also have some adverse reactions, such as foot and ankle edema, cough, headache, palpitations, etc., but professional doctors will formulate corresponding solutions according to the different conditions of patients. Don't choke on food!
Experts of this issue
Dr. Li Ling
- He served as the chairman of the Youth Committee of the Hypertension Prevention and Control Branch of Henan Medical Association
- Leader of the quality control expert group of Henan Hypertension Compliance Center Alliance
- Vice Chairman of the Hypertension Prevention and Control Branch of Henan Medical Association
- Vice Chairman of the Hypertension Professional Committee of Henan Medical Doctor Association
- Executive Director of China Hypertension Alliance
- Young and middle-aged editorial board member of Chinese Journal of Hypertension
- Academic and technical leader of Henan Province
- He is mainly committed to the clinical and research work of hypertension diagnosis and differential diagnosis. He specializes in the diagnosis and treatment of hypertension caused by various causes, including refractory hypertension and endocrine hypertension
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bibliography
1. Guidelines for the prevention and treatment of hypertension in China
2. Guidelines for rational use of drugs for hypertension