Propranolol, metoprolol, atenolol, and timolol are some of the many beta-blockers. Beta-blockers interfere with the effect of adrenaline on the heart, preventing an unnecessary increase in the speed and effort of the heart. Aside from the effect on angina pectoris and hypertension, beta-blockers can prevent and control certain kinds of abnormal heart rhythms. They can be used alone or in conjunction with digoxin, qui-nidine, or disopyramide. Usually, they are taken from one to four times daily. They slow the pulse, and some people may develop an inordinately slow heart rate. In patients with asthma or chronic bronchitis, beta-blockers may exaggerate wheezing. And in certain individuals, they may aggravate the symptoms of heart failure.
A new class of medications has become available for the treatment of angina pectoris. The calcium antagonists or calcium blockers add a new dimension to the control of angina pectoris. Many older people with anginal pain benefit from the use of nifedipine, diltiazem, or verapamil.
Medications used to treat hypertension (high blood pressure) often overlap with those used for various forms of heart disease. Diuretics (“water pills”) are medications that cause the body to lose salt and water. In people who suffer from heart failure, there is an excessive accumulation of fluid because of impaired pumping of the heart. Diuretics allow the excess fluid to be passed through the kidneys and thereby decrease the shortness of breath, bloating, and swelling.
It may be necessary to use diuretics with other medications when high blood pressure is difficult to control. The most common diuretics, the thiazides, come in many forms, as individual medications and sometimes in combination with other drugs. They are slow acting and rarely create an urgency to urinate, as do the faster-acting diuretics, such as furosemide. The fast-acting diuretics are more potent than the thiazides for the treatment of heart failure but are not more effective in treating high blood pressure. The diuretics spironolactone, triamterene, and amiloride are often combined with other diuretics to enhance their effect and prevent excessive loss of potassium, which is often a problem with the other types of medications. Sometimes potassium tablets or syrup may be given with thiazides or furosemide. Potassium should not be taken if you are receiving spironolactone, triamterene or amiloride. r
Medications for hypertension may cause an excessive loss of salt and water, which can lead to dizziness and fainting, or they may decrease the efficiency of the kidneys. In people who have a tendency to diabetes mellitus, diuretics may increase the level of sugar in the blood (see chapter 18, section on diabetes mellitus). In certain individuals gout may occur. If you are taking diuretics, expect to have periodic blood tests to measure electrolytes, blood sugar, and kidney function.
Some drugs used to treat high blood pressure act on the blood vessels, on the heart, or on the brain. Propranolol and other beta-blockers, as well as methyldopa, hydralazine, prazosin, and clonidine are effective antihypertensive medications.
Often, a combination of medications is given simultaneously. Each medication can have its own side effects. The main problem is the excessive lowering of the blood pressure, which often leads to dizziness and fainting. This can usually be reversed by decreasing the dosage. Medications known as ACE inhibitors, such as enalapril and captopril, can be prescribed for some people to lower blood pressure and/or treat heart failure. The use of these drugs must be carefully followed by your physician because they are usually started in very small doses and then gradually increased.