Medical Treatment of Angina

Today, more and more angina sufferers are being offered one of the two surgical techniques; they are now highly successful in producing lasting relief from the symptoms. However, even patients who undergo bypass surgery or angioplasty may still have to take drugs.

There are three principal drugs for angina - the nitrates, betablockers and calcium antagonists. Nitrates act mainly by opening up the veins, all over the body, reducing the demand on the heart. They may also slightly open up the coronary arteries, improving the flow of blood through them.

Nitrates. The main advantage of nitrates is that, when placed under the tongue and allowed to dissolve, they work very quickly during an angina attack. If you are given them, your doctor will explain exactly how to use them. Under-the-tongue glyceryl trinitrate quickly puts the pain away: it then must be spat out, before other arteries, like those in the head, start to expand, too, causing a splitting headache!

Under-the-tongue nitrates can also be used to ward off an expected angina attack, as before climbing up a hill that you know can bring on pain.

Nitrates are also available in a spray which you place in your mouth, or in a patch, like a sticking plaster, which delivers the active ingredient through the skin. Many put the patch on their chests, but it would reach the heart just as quickly if placed anywhere on the torso. They seem to be useful in night pain or breathlessness, but not so effective against angina provoked by exercise or effort. Some nitrates, such as isosorbide dinitrate and mononitrates, are made up as tablets, to be swallowed. Side-effects of nitrates include head­aches and flushing: if you can tolerate them for a few days, they usually disappear.

Betablockers. Betablocker tablets are the mainstay of most angina treatments. They reduce the demand on the heart, slowing the heart rate, lowering blood pressure and reducing the force of the heart beat. Each of these actions improves the balance between supply and - demand.

The slowing of the heart beat on betablocker drugs can be dramatic: it may even drop down to around 45 or 50 per minute. This is nothing to worry about, as long as you feel well on the drug.

As with all active drugs, betablockers have side-effects. They include wheezing and heart failure in people whose hearts have already been damaged so patients are carefully selected before they are given them. Other, less serious, but sometimes annoying, side-effects, may include lethargy, bad dreams, a muzzy head, inability to concentrate. All betablockers produce cold feet, some to a lesser extent than others.

There are groups of betablockers with slightly different properties, so that if you find one does not suit you, you may be offered another. A list of their prescribed names include: acebutolol, atenolol, metoprolol, nadolol, oxprenolol, pindolol, propranolol, sotalol, and timolol. There are probably many more.

Calcium antagonists. Calcium antagonists, otherwise known as calcium entry blockers, are effective in both the 'Prinzmetal' angina due to spasm of the coronary arteries and in exertional angina. They work in several ways: they may lower the blood pressure by opening up the circulation in the legs and arms; they open the coronary arteries; and they improve the efficiency of the contraction of the heart muscle cells.

Calcium antagonists went through a bad time in the mid-1990s, because there was evidence that they might lead to sudden attacks of abnormal heart rhythm and to a higher risk of sudden death. That turned out to be linked to 'short-acting' calcium antagonists, the effects of which lasted only a few hours in each day, so that between times the control of the heart's beating mechanism was lost. All the newer preparations of calcium antagonists now exert their effects for 24 hours, and the problem has been solved. Current calcium antagonists include verapamil, amlodipine, felodipine, isradipine, lacidipine, lercanidipine, nicardipine, nifedipine and nisoldipine.

Side-effects of calcium antagonists include palpitations and flushing, but they are remarkably free from serious side-effects.