Chapter 4: Medicinal treatment for hypertension
The world's statistic data has confirmed that half of the hypertensive patients did not receive any treatments, and only half of the patients who underwent the treatments attained the effective control on their blood pressure. In China, the hypertension control rates are less than 5%. Such a low control is a direct result of the high morbidity and high mortality, mainly because of the inconsistent condition between hypertension and its related symptoms. Some people may look healthy and normal, nevertheless, their blood pressure may have risen to a dangerous level, and their internal organs may have damaged badly.
Besides restricting on diet, weight, tobacco, alcohol, and doing an appropriate exercise, hypertensive patients need medication to control their blood pressure. The drugs treatment must be in accordance to the conditions and symptoms.
High blood pressure is a slow process, and hypertension treatment needs to emphasize on the stable basis, but not to be too hasty, therefore, slower treatment is always better than the quick one. Anti-hypertension drugs usually take a very long time, and sometimes patients will be lifelong medication. Ideal anti-hypertensive drug should be effective in reducing blood pressure, and the intake is once a day with fewer side effects, so that it will not indulge other cardiovascular risk factors. The drug treatment must aim at reducing blood pressure, to strengthen the heart, brain, kidney and other organs of protection.
Type of antihypertensive drugs
In modern treatment nowadays, antihypertensive drugs can group in six categories, namely, diuretics, β-blockers, calcium antagonists, angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor antagonist II (ARB) and α receptor blocker.
Commonly used antihypertensive drugs
Inhibitors: reserpine, clonidine hydrochloride, ACEI such as captopril, enalapril
Central nervous system and sympathetic: Hydrochlorothiazide, cyclopentyl A thiazides, chlorine-thiadiazole such as furosemide
Adrenergic receptor: β-blockers such as propranolol, Atenolol, the US Metoprolol; α Blockers: benzene Benzylamine
Calcium antagonists: nifedipine
Vasodilators: hydralazine, prazosin
Postganglionic sympathetic ganglion and inhibitors: guanethidine
85 - serotonin receptor antagonist: ketanserin
Characteristics of some major antihypertensive drugs
ACEI (angiotensin converting enzyme inhibitor) and the ARB (angiotensin receptor antagonist Ⅱ) are drugs that are good to protect the organ.
ACEI is mild in nature, and may long-term reduce the blood pressure and protect the organs. Their representative drug called benazepril (Lotensin), has dual-channel discharge properties, which is widely used in the treatment of hypertension. As it has a strong affinity of renal tissue, it is a good drug to protect the kidney. A recent research reports indicate that ACEI can also significantly improve the prognosis of heart failure patients.
ARB is a recently developed hypertension drugs and it is a 1990s milestone for a cardiovascular drug. Latest research has proved its safety, effective and protection for the brain and kidney. Its representative drug called valsartan, can improve the common sexual dysfunction among the hypertensive patients.
The medicinal principles for hypertension
Modern treatment of hypertension medicines consist of 6 main categories, namely, diuretics, β-blockers, calcium antagonists, angiotensin converting enzyme inhibitors (ACEI), angiotensin receptor antagonist Ⅱ(ARB) and α-adrenergic receptor blockers. Existing clinical trial results support the following types of antihypertensive drug combinations:
- Diuretics and β-blockers.
- Diuretics and ACEI or ARB.
- Calcium antagonist (dihydropyridine) and β-blockers.
- Calcium antagonist and ACEI or ARB.
- Calcium antagonists and diuretics.
- Α receptor blockers and β-blockers.
If necessary, other combinations have to include in the treatment consisting of the central role of medicine, such as α2 receptor agonist, effects of-receptor modulators, as well as the use of ACEI and ARB in the treatment.
There are two kinds of combined medication: the first is to take the prescribed medicine according to the dose ratio and adjustment of drugs base upon the variety and dosage of clinical needs. The second is fix ratio compound, which helps improve the compliance of the patients. Antihypertensive drug mechanisms and the type of the application of antihypertensive drugs, for example through diuretics to reduce the cycle of the content of sodium and water may help lowering blood pressure and blood volume. This treatment is commonly applicable to mild to moderate hypertensive patients, particularly for the elderly and for hypertensive patients with heart failure. The use of Hydrochlorothiazide, indapamide and β-blockers block β receptors, weakened myocardial contractility in order to reduce cardiac output, decrease myocardial oxygen consumption, inhibit renin secretion, slow down the heart rate and lower blood pressure and thereby significantly reducing the risk of stroke and coronary heart disease. The usage of these drugs are common in the treatment of coronary heart disease, angina pectoris, myocardial infarction as way to prevent the recurrence of accidents and sudden deaths, rapid arrhythmia, congestive heart failure and pregnancy-induced hypertension.
Propranolol, atenolol, metoprolol, Bisoprolol, carvedilol calcium antagonist (CCB) are some of the drugs used to inhibit calcium from passing through the cardiac and vascular muscle cells, lead the muscle relaxation and reduce resistance around the cells. This is particularly applicable to elderly hypertension, isolated systolic hypertension, hyperlipidemia, obese hypertension or electrolyte imbalance with heart, brain, kidney and vascular complications of hypertension particularly in pregnancy-related hypertension.
