7 Most Used Hypertension Drugs and How They Lower High Blood Pressure

The two main problems in hypertension therapy are; getting the patient to the physician and persuading his/her to continue treatment once it has begun. For a patient who had no symptoms before the treatment was begun, the symptom that can be caused by the medication may persuade him/her to discontinue treatment even though he/she knows it is keeping his blood pressure under control.

Thus patient education which is discussed in our previous post is therefore an important aspect of hypertension treatment.

Antihypertension therapy involves the use of various classes of pharmaceutical agents but the mostly used among them include the following:

Diuretics: This type of medication lowers blood pressure by reducing the blood volume as a result of increased sodium and water excretion. The special form of diuretics is the thiazide diuretics which is one of the first-line drug treatments for hypertension because of its slight vasodilating effect. It is taken either as monotherapy or in combination with calcium channel blockers (CCBs), angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs).

Unfortunately none of the drugs used in antihypertensive therapy is without adverse effects. Perhaps, the most pronounced adverse effect of the thiazide diuretics is potassium depletion, which causes a feeling of fatigue and weakness (and thus may make patient feel worse than he did before treatment). This problem can be avoided however, by replacement of the potassium, either in the form of medication (slow-k) or in the form of fruits such as bananas and oranges that are high in potassium. Other possible side effects of the thiazide diuretics are increased blood glucose, nausea and cardiac arrhythmia.

It is contraindicated in patients with: gout, hypokalemia, hypotension, renal failure, allergy to sulphur medication, lithium therapy and it may worsen diabetes. They also decrease placental perfusion and adversely affect the fetus so should be avoided in pregnancy. Examples of diuretics include: hydrochlorothiazide or microzide, chlorthalidone or thalitone etc.

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Direct Acting Vasodilators: They act directly on the smooth muscle of arteries to relax their walls so that blood can move easily through them. They are mostly used in hypertensive emergencies (180/120mmHg and above) or when other drugs have failed and even so are rarely given alone. These drugs may increase the cardiac output to the point that angina pectoris (the sensation of chest pain , pressure, or squeezing, often due to ischemia of the heart muscle from obstruction or spasm of the coronary arteries) or even myocardial infarction can occur. Examples include; Nitropress (sodium nitroprusside), hydralazine, etc.

Sympathetic Blockers: This group of drugs reduces the workload on the heart and open blood vessels causing the heart to beat slower and with less force. When prescribed alone they don't work as well especially in older adults but may be effective when combined with other blood pressure drugs. They may cause depression of cardiac activity and bronchial contraction. Examples: acebutolol (sectral), atenolol (tenormin), propranolol, etc.

Angiotensin-Converting Enzyme (ACE) Inhibitors: ACE inhibitors relaxes blood vessels blocking the formation of a natural chemical (angiotensin ll) that narrows blood vessels (vasocontriction). Examples; zestril, captopril, benazepril, etc.

Angiotensin ll Receptor Blockers (ARBs): ARBs relaxes blood vessels by blocking the action (not the formation) of a natural chemical (angiotensin ll) that narrows blood vessels. They are called the Sartans, examples include; losartan, valsartan, candesartan, etc.

Calcium Channel Blockers (CCBs): They relaxes the muscles of blood vessels by blocking the entry of calcium into the muscle cell in the arterial walls. A patient taking these medications should be discouraged from taking grapefruit juice because it interacts with some CCBs and increases blood level of the medication. Examples; amlodipine, diltazem, etc.

Renin Inhibitors: This group of drugs slows down the production of renin, an enzyme produced by the kidneys that starts a chain of chemical steps that increases blood pressure. A good example is alikiren (tekturna). Due to risk of serious complications, including stroke, alikiren should not be taken with ACE inhibitors or ARBs.