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If you have missed one dose and your next one is already due, just take one dose – DON’T take an extra dose next time. Be especially careful not to miss any further doses.
If you forget to take your blood blood-pressure treatment for more than one or two days, contact your doctor for further advice.
Tips to Help You Remember to Take Your Medication
Try to take your blood-pressure treatment regularly, at the same time every day, so you get into a routine.
Write a note for yourself and stick it where you will easily see it.
Keep your tablets/capsules where you can remember them easily, such as with your toothpaste (but make sure they are out of the reach of children).
Keep your tablets in a special dispenser box marked with separate containers for different times of the day.
If you have a programmable alarm watch, set it for when your medicine is due.
If you live with someone else, ask them to help you remember.
Make sure you get your next prescription in plenty of time so you don’t run out.
If you are going away, take enough tablets with you to last the whole time.
DRUGS TO LOWER HIGH BLOOD CHOLESTEROL
The best way to reduce high cholesterol is through making dietary changes and increasing the amount of exercise you take. Doctors usually recommend a low- fat diet, using olive or rapeseed oil for cooking, eating oily fish, taking fish oil supplements and garlic powder tablets.
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:
angina
had a heart attack
had a coronary artery by-pass graft or dilation (angioplasty)
had surgery for poor circulation in the limbs
diabetes
several major risk factors for CHD.
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.
PART TWO High Blood Pressure and Diet (#ulink_fe9359f8-e2bf-5893-b7d3-3fb51cebf295)
CHAPTER 3 Atherosclerosis, Cholesterol and Dietary Fats (#ulink_96e71b6c-b426-5d62-b055-0e7b8a2f82c7)
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 the heart is resting between beats – also becomes raised. Atherosclerosis can therefore raise both diastolic and systolic blood pressure. If left untreated, the raised BP in turn causes damage to the arterial system, hastening the development of atherosclerotic plaques and causing blood pressure to rise even further.
As a result, the heart has to pump blood out into a circulation whose vessels are narrowed and have lost their elasticity. This increases the workload of the heart – which has to pump blood out into the high-pressure system – and its need for oxygen increases at a time when its blood supply is often already compromised due to atherosclerosis of the coronary arteries. As the heart muscle beats over 100,000 times per day, lack of oxygen rapidly leads to muscle cramping, making angina and a heart attack more likely. In some people, two-thirds or more of a coronary artery may be furred up and blocked without causing symptoms. In others, angina may be triggered even though only a small plaque is present and the coronary artery is narrowed only slightly. It all depends on:
the exact site where the atheroma and narrowing have developed – the most common is within 3cm of where a coronary artery originates from the aorta, so the effects of ischaemia (lack of blood supply) are likely to be more widespread and serious
how well the two main coronary arteries join up to share the load of supplying blood
how good the blood supply from the other coronary artery is
the type of coronary arteries you have inherited – whether they are the vascular equivalent of motorways or winding country lanes.
Cholesterol Levels
Fats from your food are processed in the small intestines to form fatty globules (chylomicrons) bound to carrier proteins, which together form substances known as lipoproteins. After a fatty meal, there may be so many of these fatty particles in the circulation that blood takes on a milky-white appearance. These fatty globules are cleared from your bloodstream by the action of an enzyme (lipoprotein lipase) found in the walls of blood capillaries. Some of the fat released in this way is taken up into cells, while some remains in the circulation and is transported to the liver. In the liver, the fats are processed, packaged to different types of carrier proteins and passed out into the circulation again for further distribution around your body.
There are two main types of circulating cholesterol:
low-density lipoprotein (LDL) cholesterol, which is linked with hardening and furring up of artery walls, high blood pressure and coronary heart disease
high-density lipoprotein (HDL) cholesterol, which protects against atherosclerosis and CHD by transporting LDL-cholesterol away from the arteries for metabolism.
Research shows that for every 1 per cent rise in beneficial HDL cholesterol, there is a corresponding fall in the risk of CHD of as much as 2 per cent. This seems to be due to reversed cholesterol transport in which HDL moves LDL cholesterol away from the tissues and back towards the liver.
It is, therefore, not so much your total blood cholesterol level that is important when it comes to atherosclerosis but the ratio between beneficial HDL cholesterol and harmful LDL cholesterol. If you are told you have a raised blood cholesterol level, it is important to know whether your LDL or HDL cholesterol is high:
if your blood fats consist mainly of HDL-cholesterol, your risk of CHD is significantly reduced
if most of the lipids are in the form of LDL-cholesterol, with low HDL levels, your risk of CHD is significantly increased. Ideally, total cholesterol level should be less than 5mmol/l, with LDL cholesterol less than 3mmol/l.
Where LDL cholesterol levels are raised, it is estimated that reducing the average total blood cholesterol level by 10 per cent could prevent over a quarter of all deaths due to coronary heart disease. Unfortunately, attempts to reduce dietary cholesterol for improved cardiovascular health often have the opposite effect. Rather than just lowering the potentially harmful LDL form of cholesterol, dietary interventions often reduce levels of beneficial HDL-cholesterol as well. This is because the types of fat in your diet are also important, and people often cut out the good fats as well as the less desirable ones. If you ate all your fat in the form of essential fatty acids, monounsaturated fats (e.g. olive oil) and fish oils, for example, your risk of CHD would be low as most circulating fats would be in the form of beneficial HDL-cholesterol.
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