If dietary changes have failed, your doctor may prescribe a lipid-lowering drug. This would be in instances where total blood cholesterol is above 7.8 mmol/l and is mainly in the form of harmful LDL-cholesterol.
In some cases, raised cholesterol levels are due to hereditary difficulties with fat metabolism. In these instances, one or more drugs often have to be prescribed.
Resins
Resins (e.g. cholestyramine, colestipol) work by binding to bile acids and preventing their reabsorption in the gut. This interferes with regulatory messages feeding back to the liver, so that more cholesterol is broken down into bile acids and excreted from the body. These drugs can lower LDL-cholesterol levels by up to 25 per cent on top of that achieved through dietary changes. Unfortunately, they cause triglycerides – another type of dietary fat linked to heart disease – to rise by up to 5 per cent. They are mainly used when a statin cannot be taken (see below). Side-effects include constipation and, in long-term treatment, a lack of fat-soluble vitamins A, D, E and K.
Fibrates
Fibrates (e.g. bezafibrate, ciprofibrate, clofibrate, fenofibrate, gemfibrozil) work by lowering liver synthesis of cholesterol. They reduce total cholesterol by up to 25 per cent and triglycerides by up to 50 per cent. They also have a beneficial effect on types of cholesterol in the blood, raising HDL and lowering LDL cholesterol. Unfortunately, they can trigger muscle pain (myositis), especially in patients with kidney disease. Some encourage gallstones and inflammation of the gall bladder by increasing excretion of cholesterol into the bile. Other possible side-effects include fatigue, muscle cramps, dizziness, painful extremities, hair loss, blurred vision, impotence and, rarely, inability to feel sexual pleasure.
Statins
Statins (e.g. fluvastatin, pravastatin, simvastatin) work by inhibiting a liver enzyme and lowering cholesterol production in the liver. LDL-cholesterol can be reduced by up to 40 per cent, with a beneficial rise in HDL-cholesterol and a moderate reduction in triglycerides. Statins are very popular drugs as they significantly reduce the risk of heart disease and stroke. Side-effects include reversible muscle problems, non-cardiac chest pain, diarrhoea, constipation, sinusitis, insomnia, flatulence and fatigue. Side-effects may be reduced by taking co-enzyme Q10 supplements.
Nicotinic Acid Derivatives
These drugs (e.g. acipimox, nicofuranose, nicotinic acid) lower both triglycerides and cholesterol levels by inhibiting the breakdown of body fat stores and the inhibiting production of fats in the liver. LDL-cholesterol can be lowered by up to 20 per cent and HDL-cholesterol is increased. They are limited by their side-effects of dilating the blood vessels dilation, causing dizziness, headaches and flushing.
Marine Fish Oils
Marine omega-3-triglycerides are a natural product that reduces blood levels of cholesterol and harmful triglycerides by inhibiting their production in the liver. They make the blood less sticky and reduce the risk of arterial thrombosis. They have few side-effects apart from possible nausea (if too much is taken) and belching. If diabetic, monitor blood gluscose levels carefully when starting to take them.
Probucal
This drug is in a class of its own, and its precise mode of action is unknown. It seems to increase excretion of bile acids in the faeces, so that more cholesterol is broken down in the liver to replenish them. It can lower LDL-cholesterol by up to 10 per cent, but HDL-cholesterol is reduced as well. Triglycerides remain unchanged. Probucal also acts as an antioxidant. Possible side-effects include flatulence, diarrhoea, mild abdominal pain and, very rarely, abnormal heart rhythm.
Aspirin
Aspirin is a commonly used pain killer and anti-inflammatory drug that also has a powerful blood-thinning effect. It lowers the stickiness of platelet particles in the blood so that they are less likely to clump together and form unwanted clots. This effect occurs at only a quarter of the dose needed to relieve pain. Although there is not yet felt to be enough evidence to recommend that everyone takes preventive aspirin, people who may be advised to take a regular mini-dose of aspirin every day include those who have:
Studies show that taking low-dose aspirin (75mg–150 mg) per day can reduce the risk of a heart attack or stroke by 30 per cent, and the risk of dying from them by 15 per cent (see Chapter 3).
If you fall into any of the above groups and are not taking a junior aspirin per day, check with your doctor that it will suit you and fit in with any other medication that you are taking.
CHAPTER 3 Atherosclerosis, Cholesterol and Dietary Fats
People with hypertension need to pay particular attention to the fats in their diet. By eating more of certain beneficial fats and less of potentially harmful ones, you can reduce your risk of future complications such as atherosclerosis.
Atherosclerosis
Atherosclerosis is the medical term for hardening, furring up and narrowing of the arteries. This process starts early in life, usually in the teens, and is triggered by normal wear-and-tear damage to your artery walls. Once the damage occurs, small cell fragments in the bloodstream – known as platelets – stick to the damaged area and form a tiny clot. These platelets release chemical signals to stimulate healing of the damaged area. Under normal circumstances, this would lead to healing, but if excessive damage continues – as a result of high blood pressure, raised cholesterol levels, poorly controlled diabetes or lack of antioxidants in the diet – the damaged area becomes infiltrated with a porridge-like substance that builds up to form a fatty plaque known as atheroma.
At the same time as the fatty plaques are developing, the underlying middle layer of the artery wall is affected and starts to degenerate, become fibrous and less compliant. Whereas the walls of healthy arteries are elastic and help to even out the surges of blood pressure produced every time the heart beats, the walls of arteries that have started to harden become more rigid. As a result, blood-pressure surges caused by the heartbeat are not evened out, and systolic blood pressure shoots up higher when the heart contracts. A vicious cycle then sets up, for just as atherosclerosis leads to high blood pressure, untreated hypertension can also lead to atherosclerosis by damaging artery linings and hastening the hardening and furring-up process.
If atherosclerosis is widespread throughout the body, it narrows the circulation so the diastolic BP – the pressure in the system when