Last partial update: September 2022 - Please read disclaimer before proceeding.

 

Why do Australians need to worry about blood pressure?

Incidence

Hypertension affects about 28 per cent of Australian adult males and females (3.5 million people), with its incidence increasing with age. About 66 per cent of 70 year olds have high blood pressure.

Disturbingly, about 56 per cent of Australians (2 million people) requiring treatment for their high blood pressure are inadequately managed. In half of this group the problem is that their blood pressure remains undiagnosed and in the other half it is that their treatment is inadequate.

 

Hypertension graph 1

Source: Adapted from Australian Institute of Health and Welfare: Begg, S. 2007.

 

Consequences of high blood pressure

High blood pressure is responsible for about eight per cent of all illness in Australia; a huge amount!!! Most of this is due to its influence on three very important diseases; heart attacks, strokes and heart failure.

Worldwide it is the most important cardiovascular disease risk factor.

In most cases this damage occurs slowly over a long period of time and thus the age of onset of the hypertension is important in determining the extent of the damage that eventually occurs. Occasionally, when blood pressure is very high, illness due to blood pressure such as strokes can come on relatively quickly. This is why people with very high blood pressure sometimes need to be treated in hospital.

The effects of hypertension are worsened by all other risk factors for vascular disease and by other factors including excessive alcohol consumption.

Benefits of preventing hypertension or managing hypertension well

Long term treatment that provides good control of blood pressure can reduce the risk of the above diseases significantly. A reduction in stroke incidence of 28% can be achieved with only a modest lowering in blood pressure and the risk of stroke halves for each 10mmHg drop in diastolic blood pressure (the lower reading).

Check blood pressure at least every two years:
To reduce the risk of illness from hypertension, all Australian adults should have their blood pressure checked at least every two years and be aware of lifestyle measures they can adopt to help prevent this disease or reduce its severity, including maintaining a healthy weight, increasing physical activity and consuming a healthier diet, especially reducing excess sodium (salt) intake. Those Australians with hypertension need to make sure their blood pressure is well controlled (with medication if needed) through regular monitoring by their doctor.

Lowering the systolic (upper) blood pressure level to 120mmHg in people at high risk of cardiovascular disease has significant benefits

People at high risk of cardiovascular disease (See section of assessing overall cardiovascular disease risk.) benefit greatly from maintaing the upper blood pressure reading (the systolic blood pressure) at or below 120mmHg. Doing so reduces the risk of a major cardiovascular event (heartt attack, stroke, heart failure etc) by about 25% and reduces the overall risk of dying from all causes by about 27%. These are massive benefits. This includes older people. (In the past it was incorrectly thought that lowering blood pressure too much in older people could cause harm. Unfortunately in some people this is difficult to achieve but just trying has been shown to provide benefit in this high risk group. Overall, to reduce one death by lowering systolic BP to 102mmHg in this group, about 90 people had to be treated and to prevent the occurrence of one major cardiovascular event, about 60 people needed to be treated.

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What is blood pressure and how is it measured?

Blood pressure is the measurement of the pressure of the blood in large arteries. (Arteries are the vessels that take blood from the heart to the other body organs.) This pressure is provided by the pumping of the heart. Blood pressure is needed so that blood can be forced through the arteries that progressively decrease in size from the heart to the body tissues they supply.

Blood pressure readings are measurements of pressure experienced by blood in the main artery in the upper arm. The higher level, called the systolic blood pressure, is read just after the heart has pumped, when the pressure is at its greatest. The lower level, called the diastolic blood pressure, is read just before the heart pumps again, when the pressure is at its lowest.

Both readings are important in assessing blood pressure as an elevation in either, or worse both, increases the risk of heart attacks and strokes.

Blood pressure is best measured in a seated position (or lying) after five minutes rest. The person should not have consumed caffeine or inhaled nicotine (smoked) in the previous two hours.

Some people are likely to have a lower blood pressure when standing up and if it goes low enough this can cause them to faint if they get up quickly (termed postural hypotension). Such people should also have their blood pressure measured when standing. They include:

Blood pressure measuring equipment needs to be accurate. People who check their blood pressure at home should ask their doctor to recommend a good device and their doctor should check the equipment initially to ensure it is accurate and the arm cuff is the correct size. (Children and some obese people need different sized cuffs to those normally supplied.) Rechecking equipment regularly for accuracy is recommended. Wrist and finger devices for checking blood pressure are less accurate and are not recommended.

What is a normal blood pressure?

Generally speaking, the blood pressure a person should aim to stay below (their target blood pressure) varies with the person's overall risk of cardiovascular disease. (See section on assessing cardiovascular disease risk for more information.)

It is important to realise that high blood pressure is not a disease; it is a risk factor for cardiovascular diseases such as heat attacks and strokes. Thus, whether your blood pressure is problem that requires treatment really depends on what your overall cardiovascular disease risk is. (See section on assessing cardiovascular disease risk for more information.)

While evidence suggests that in most people any lowering of systolic blood pressure (the upper reading) towards a level of 115mmHg or diastolic blood pressure (lower reading) towards a level of 75mmHg helps reduce risk of cardiovascular disease, the benefit will be quite small for those with a low risk overall risk of cardiovascular disease and in most cases people at low risk of cardiovascular disease should not be on medication to lower blood pressure. On the other hand, the benefit of lowering systolic blood pressure can be substantial for those at high overall risk and these people are likely to benefit from taking medication.

Having said this, the Heart Foundation’s optimum BP levels for people who do not have other factors that increase their risk of cardiovascular disease are as follows:

Lifestyle measures to maintan a low blood pressure, such as regular exercise, maintaining a healthy weight and reducing salt intake are helpful for many reasons and should be a goal for everyone. For the majority of people achieving the above blood pressure levels is more than adequate and further reduction below this level provides little extra benefit. Only people at a higher overall risk of cardiovascular disease need to take medication to ensure that their blood pressure was maintained at a systolic level below 125mmHg. Target blood pressures are discussed more fully later in this chapter.

A diagnosis of hypertension should not be made on a single reading, unless it is very high. As a rule, several readings should be taken over a period of a one to three months, depending on the situation.

What causes high blood pressure?

All people diagnosed with hypertension need to be investigated by a doctor to identify any possible underlying cause for their high blood pressure. However a cause is not usually found. Occasionally people with no initial identifiable cause can develop an identifiable cause later in life. This is often signified by a sudden worsening of their blood pressure.

A specific cause is more likely to be the case when hypertension occurs in a younger person or when it is difficult to control with medication. Some of the more common diseases causing hypertension include:  

It was thought that only about 5% of people with high blood pressure having an identifiable disease causing the problem but the figure may well be higher than this. The reason is:

Conn's Syndrome: Recent research has suggested that the incidence of Conn's Syndrome (primary aldosteronism) is significantly higher than previously thought; causing perhaps 10% of all cases of hypertension. It is caused by excess secretion of the hormone aldresterone by the adrenal glands. These lie above each kidney and the oversecretion can be caused by one or both glands  This disease can be easily diagnosed by a blood test and this test is usually done when a person is initially diagnosed with high blood pressure. However this is not always the case and it can sometimes missed early in the disease. Also, already being on medication for blood pressure medication can cause the blood test to be normal. This condition should be suspected and tested for in anyone who has blood pressure that is hard to control. (The test needs to be done with the patient off medication that might affect the result and this needs careful supervision by the person's doctor.)  There is a specific medication for this treating this condition called spironolactone. Also, if only one adrenal gland is the cause, it can be removed in some patients.

Home blood pressure (BP) readings

Up to 20% of people with normal blood pressure will have a raised blood pressure reading in the doctor’s surgery. For this reason, taking additional blood pressure readings at home should be offered to anyone with a BP greater than 140/90 before hypertension is diagnosed. (See below.)

BP readings taken away from the doctor’s surgery are becoming increasingly important in managing BP for several reasons, including the following.

Having said this, studies done on blood pressure and its treatment have almost all used readings taken in a doctor’s surgery or a clinic. For this reason it is important not to disregard high readings taken in the surgery, even if those outside are all normal.

BP readings can be taken outside the doctor’s surgery by two different methods; self monitoring or 24 hour ambulatory monitoring.

BP readings taken outside the doctor's surgery

This option should be offered to anyone with a BP greater than 140/90 before a diagnosis of hypertension is made.

24-Hour ambulatory monitoring

This technique randomly measures BP over a 24-hour period via a blood pressure cuff that is attached to the patient thoughout this period. It can be used to help diagnose high BP, or in a monitoring role in people with BP that is difficult to control or who are at high risk of cadiovascular disease. It is also used to help diagnose ‘white-coat’ hypertension. (See above.)

Normal ambulatory BP readings should be less than 135/85 during the day and less than 120/75 at night. The average over 24 hours should be less than 130/80. Elevated night time blood pressure readings are a particularly important marker of cardiovascular disease risk and a difference of less than 10 per cent between average day and night time blood pressures also indicate increased risk.

Self monitoring

Self-monitoring can be used to help make an initial diagnosis and for continued monitoring of BP. The patient can take readings when they decide, allowing multiple readings in a variety of ‘normal’ situatons. To minimise errors, it is important that the following occurs.

  • Patients are trained to use equipment properly.
  • The devices should be fully automated and have a memory so that obersver bias is not a problem.
  • The equipment is accurate. (Pharmacists and GPs can recommend good devices.)

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Prevention of hypertension

As hypertension is a very common disease in adult Australians, everyone needs to consider adopting the measures mentioned below to prevent this disease. These measures are especially important for those with an increased risk of developing hypertension, including the following.

Ways of helping reduce / prevent hypertension
A variety of lifestyle changes can help reduce / prevent hypertension, including the following. (Reducing sodium in the diet is dealt with in detail below. The other measures mentioned are covered in other sections of this web site.)

  1. Restricting sodium intake (mostly as salt)
  2. Eating more vegetables and fruit and less saturated fat.
  3. Maintaining a healthy alcohol intake or refraining from consuming alcohol.
  4. Maintaining a normal weight.
  5. Increasing physical activity.
  6. Quitting smoking

Adopting the above measures can;

Effect of improving lifestyle choices on

blood pressure

Lifestyle problem

(optimum target)

Estimated reduction in systolic (upper) BP level

Inadequate physical activity*

(moderate intensity 3 to 4 times a week)

4 mmHg*

 

Excessive weight

(Body Mass Index less than 25)

Up to 2 mmHg for each kg of weight lost. (The rate lessens as weight reduces.)

Excessive sodium consumption

(100mmol per day or (preferably) less)

5 to 7 mmHg

(This effect takes several months to occur.)

Excessive alcohol consumption*

(Less than 4 standard drinks per day for men and 2 for women.)

3 to 4 mmHg*

Excessive saturated fat consumption*

(Less than 10% of total energy intake)

2 to 3 mmHg*

* Successfully overcoming this lifestyle factor has an additional benefit through increasing weight loss.

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1. Restricting sodium intake

What are salt and sodium and how much do we need and consume?

Excess sodium in the diet increases the risk of developing high blood pressure. There are numerous sources of dietary sodium, the most common one being normal table salt (i.e. sodium chloride). Other common sources include MSG (monosodium glutamate), baking powder (sodium bicarbonate),and sodium salts used in emulsifiers and preservatives, such as sodium metabisulphite. This section will therefore mainly refer to sodium rather than salt.

To maintain normal body function, people only need an intake of 8.5mmol/day (200mg/day) of sodium. To prevent hypertension, the National Health and Medical Research Council recommends a maximum daily intake of sodium for adults of 40 to 100 mmol/day (or 920 to 2300 mg/day). Adverse effects on the body start to occur at an intake of about 50mmol/day. In Australia, only about six per cent of males and 36 per cent of females have sodium intakes less than 100mmol/day, with the average Australian diet containing about 100 to 200 mmol/day (or 2300 to 4600mg / day) of sodium.

Roughly 90 per cent of the sodium consumed in the diet is excreted in urine. Thus, if required, a doctor can easily determine a person’s daily sodium intake by collecting their urine for 24 hours and measuring the sodium content.

Reducing salt intake has been shown to significantly reduce both systolic blood prrssure (the upper reading) and diastolic blood pressure (the lower reading) in people with high blood pressure. Not surprisingly, this effect is much less in people with normal blood pressure. (They are probably consuming less sodium in the first place.) 

Children's salt intake in Australia: About 70% of children had sodiu intakes greater than recommended and many had similar intakes to adults. This has serious repurcussions for their likelihood of suffering from high blood pressure and stroke in later life. Much of this intake (40%) comes from breads and cereals. Some cereals have a particularly high sodium content and unfortunately only about 20% of Australian breads comply with the National Heart Foundation sodium benchmark standard.

Reducing dietary sodium

A major problem associated with reducing sodium intake is that in the average Australian’s diet, only 20 per cent of the sodium consumed is added by the consumer. The other 80 per cent is already added to bought foods (70 per cent) or is naturally occurring in food (10 per cent).

The main foods that contribute to sodium in the diet are bread, spreads such as butter and margarine, cheese, biscuits, takeaway foods, and sauces. (A list of the foods that people need to monitor if they are to reduce their sodium intake can be found in the boxed section below.) The contribution of each food to sodium intake depends on the amount of the food the person eats as well as the sodium content of the food. For example, the vegemite in a vegemite sandwich has a much higher sodium concentration than the bread, but the bread provides more sodium because there is much more of it.

Some foods with large amounts of sodium

Very high sodium content  (over 1000 mg of salt in 100 grams of food)
Anchovies, meat tenderisers, MSG, soy sauce (even the low salt variety), gravy powder, normal salt, stock cubes, meat extract, ham, salami, corned beef, meat pies, bacon, sausages, spring rolls, dim sims, smoked salmon, salted pretzels, parmesan cheese, blue-vein cheese, cheese spread, processed cheddar cheese, olives, kelp, normal baking powder, crumpet, flavoured cracker biscuits.

High sodium content (400 to 1000 mg of salt in 100 grams of food )
Bread, luncheon meat, pate, potato crisps, frankfurts, pizza, hamburger, fried takeaway foods, canned / packet soups, canned fish (salmon, tuna), butter, hard cheeses, pies, sausage rolls, Chinese and Lebanese foods, savoury biscuits, some cereals (Corn Flakes, Rice Bubbles, Special K, Coco Pops, Frosties, Nutri-grain, Fruit Loops, Weeties, Lite Start), some soda waters, most sauces (excluding mayonnaise, coleslaw dressing, Italian dressing)

Medium sodium content (120 to 400 mg of salt in 100 grams of food)
Sweet biscuits, salted nuts, canned vegetables, toasted muesli, cheesecake, cottage cheese and ricotta, mozzarella cheese, hot chips, caramels, toffee, pastry, cakes.

Many of the above products do come in salt-reduced / low salt varieties. This should be evident from the product information on the label.

Some foods taste ‘salty’, making their high sodium content obvious. However, many foods are able to hide their added sodium quite well so that it is difficult to taste. The sugar in sweet processed foods hides the taste of sodium very well; for example in cakes, biscuits and some breakfast cereals. The sodium added to cakes and biscuits comes mainly from the baking powder or flour (especially self-raising flour) used in their preparation.

Bread is a very important source of sodium and contributes about 25 per cent of daily sodium intake. There are some ‘salt-reduced’ breads and it is important to purchase these types of bread when seriously attempting to reduce dietary sodium intake. People can also make their own ‘no added salt’ bread at home. The sodium content of ‘normal breads’ does vary, so if a ‘low-salt’ variety is not available, look at the product information on the packaging to find out which has the least sodium. Similarly, breakfast cereals vary widely in their sodium content, so try to choose one with a low level.

With regard to the rest of the diet, the best way to reduce sodium intake is to reduce the quantity of prepared foods purchased. Try to prepare as many meals as possible at home from fresh ingredients or ingredients that are labelled ‘salt reduced’ or ‘no salt added’.

Many brands of packaged products used in home cooking, such as tomatoes and stocks, have no salt added. There are even unsalted peanut butters. Look for these rather than the ones with added salt. They will normally have ‘no added salt’ displayed on the label. People can also tell by looking at sodium content data displayed in the ‘nutritional information’ label.

If the family is used to having salt added to their food, ask them to be patient. Although their food will initially taste different, they will usually get used to the difference in about two to three weeks and eventually they will prefer their food without salt. The impact of reducing salt in meals can be lessened by adding flavour substitutes, such as herbs, curry spices, garlic, onion, lemon, lime, vinegar, plum jam etc.

Blood pressure reduction with sodium restriction takes several months

When trying to reduce blood pressure by reducing salt intake, please remember that it takes about three months for any effect on blood pressure to occur. A low salt diet in a person with normal blood pressure will not reduce their blood pressure significantly.

Labelling and ‘salt reduced’ foods

There are now low salt alternatives for many foods traditionally high in sodium, such as sauces and spreads. There are several different label wordings that indicate a reduced salt level. These labels are as follows.

A ‘Low salt’ label, which indicates that the product contains less than 120 mg of salt per 100 grams of food. (This is equal to 0.3 per cent salt content.)

A ‘Salt free' or 'Unsalted' or 'No salt added’ label, which indicates that the product contains no added salt and has been made from products that have not had any salt added.

A ‘Salt reduced’ label, which indicates that the product contains at least 25 per cent less salt than its regular counterparts.

 

Who should be careful about going on a low salt diet?

People should consult their doctor before commencing a low-sodium diet if they have a kidney or gastrointestinal disease that causes them to lose sodium or if they are on any of the following medications: blood pressure medication, fluid tablets (diuretics) or lithium.

Women who are pregnant should keep to their usual sodium intake.

People should not use potassium chloride based ‘salt substitutes’ if they have kidney disease or with certain fluid tablets (ask a doctor).

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2. Eating more vegetables & fruit & less saturated fat

Increasing the amount of fruit and vegetables consumed and reducing the intake of foods high in saturated fats (and limiting sugar) can significantly lower blood pressure and these blood pressure changes occur irrespective of whether weight loss accompanies the dietary changes.

When salt reduction is added to this diet, the reduction in blood pressure is understandably even greater and can enable some people taking medication for hypertension to stop this medication. The fact that this type of diet can also significantly reduce coronary artery disease and several important types of cancer, and helps maintain a normal weight, which in turn helps reduce diabetes type 2, makes a compelling argument for its adoption.

3.Refraining from excessive alcohol consumption

Maintaining an optimal alcohol consumption of a maximum of two standard drinks per day can help reduce blood pressure. Any increase above this level can result in an increase in blood pressure and an increase in the incidence of strokes. All people should consider having two alcohol-free days each week to help avoid possible addiction to alcohol occurring.

4.Maintaining a healthy weight

Being overweight is a significant cause of high blood pressure. The cornerstones in treating excess weight are:

5.Caffeine and hypertension

Caffeine is an addictive drug and it may cause a slight increase in blood pressure for a couple of hours after it is consumed. However, there is no evidence that it increases blood pressure in the long term and there is no evidence that consuming it increases the overall risk of cardiovasular disease. It is safe to consume in moderation although its stimulatory effects can result in problems with sleep and, when consumed in larger doses, hand tremors. See section on caffeine.

The commonest sources of caffeine are, in order of content per serving, fresh coffee (80-90mg of caffeine), energy drinks (80 mg), alcohol products that also contain caffeine (80mg), instant coffee (60-90 mg), strong tea (50-60 mg), 375ml cans of cola drink (30-50 mg), weak tea (20-30 mg) and chocolate products, including cocoa, hot chocolate and chocolate bars. Coffee is discussed in more detail in the nutrition section.

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 Treatment of hypertension

For people with no identifiable cause for their raised BP (95% of cases) who do not respond adequately to lifestyle measures, treatment of their hypertension relies on the use of drug therapy; and the majority of people will need more than one medication to achieve good BP control. There are numerous drugs available and the decision regarding which drug combination is most suitable for a person depends on numerous factors, including the following.

Three important points

  • All vascular disease risk factors need assessment: People with high blood pressure need to be assessed for their overall risk of vascular disease (heart attacks and strokes). This means assessing all vascular disease risk factors, not just blood pressure. People with multiple risk factors who are at high overall risk of vascular disease need their high blood pressure treated more aggressively.
  • Older people benefit significantly from blood pressure treatment: Treating hypertension is just as beneficial in reducing the risk of strokes and heart attacks in older people as it is in younger adults.
  • People with high blood pressure need to be assessed for complications of the disease, including heart failure and eye and kidney damage.

When to start therapy

As stated before, the National Heart Foundation’s optimum blood pressure level is 130/85 or less for those under 65 years, and 140/90 for those over 65 years. 

The aim of treating blood pressure is not to make people feel better, it is to reduce the risk of developing cardiovascular disease (i.e. heart attacks and strokes). There are numerous factors in addition to blood pressure that determine a person’s overall cardiovascular disease risk level and all adults, especially those over the age of 40 years, should know their cardiovascular risk level. See section on assessing your risk of cardiovascular disease.

It is important to understand that reducing blood pressure will reduce cardiovascular risk irrespective of the reason for the person's high risk status AND irrespective of the starting blood pressure level. This is a very important concept to grasp because it means that taking medication to lower blood pressure may be appropriate for people with normal blood pressure (as you can have a normal blood pressure and still have a high risk of cardiovascular disease).

Conversely, in people at low overall risk of cardiovascular disease, there may be no need to talke medication for mildly raised blood pressure. (BUT lifestyle factors should still be adopted.) For example, a recent major review of research into the treatment patients with low overall risk of cardiovascular disease found that there was no benefit in treating these patients when they only had mildly raised BP (systolic of 140 to 159 and / or diastolic BP of 90 to 95). The National Heart Foundation of Australia's recommended starting and target blood pressure levels are shown in the tables below.

Thus, while everyone with a raised blood pressure level should adopt lifestyle measures to try to reduce it, whether or not a person starts blood pressure lowering medication depends on their cardiovascular risk level.

 

Target BP levels and when to initiate BP medication*

(These levels are a guide only and patients need to decide on appropriate levels with the help of their doctor!!)

Population groups according to cardiovascular risk level

(in order of most to least cardiovascular risk)

(See section on assessing your risk of cardiovascular disease to determine your risk level.)

BP level at which to initiate drug therapy

Target BP

(less than the readings below)

 

Patients at highest risk of cardiovascular disease

(This includes people in a high risk group or a person who has a five year CVD risk of greater than 15%. Importantly it includes all people with a past history of CVD).

(All people at high CVD risk should also be on medication to lower their choesterol and those who have a past history of CVD should also be considered for treatment with anti-plsatalet therapy.)

 

All people in this group should be on medication to lower blood pressure irrespective of their blood presure level at diagnosis. The exception is people with low blood pressure who may become ill if their BP is lowered further.

Systolic BP 125

 AND

Diastolic BP 75

Patients at a moderately increased risk of cardiovascular disease (a five year risk of CVD of between 10 and 15%) who also have any of the following

  • CVD risk does not deceare with six months of lifestyle modification
  • BP is greater than 160/100
  • there is a family history of premature CVD (before 60 yrs)
  • the person is in a high risk ethnic group (Indigenous Australians and Torres Strait Islanders, Maoris, people from South East Asia, the Pacific Islands and the Middle East.
  • mildly reduced kidney function ( or have 0.25g to 1.0g of protein in their urine per day)

(All people in the above groups are need to adopt lifestyle modification to lower their risk. Many should also be considered for therapy with cholesterol lowering medication.)

All people in this group should be on medication to lower blood pressure irrespective of their blood presure if, persistently, their systolic blood pressure is greater than 140 or their diastolic pressure is greater than 90. (The exception is people with low blood pressure who may become ill if their BP is lowered further.)

 

 

Systolic BP  130

AND

Diastolic BP  80

 

Patients at low risk of cardiovascular diseas (a five year CVD risk of less than 10%)

  • The decision regarding whether to start blood pressure lowering medication and when to do it depends on their blood pressure when hypertension is diagnosed
  • In practice, this means that quite a number of young people with mildly elevated blood pressure are at low CVD risk and do not need to take medication (while they are young).
  • However, ALL people with low CVD risk and a raised blood pressure should adopt lifestyle measures to reduce their blood pressure.

Systolic BP below 160 and Diastolic BP below 100

- No medication required.

 

 

Systolic BP 160 to 180  or

Diastolic BP  95 to 100

- This group should only start medication if there has been an inadequate lowering of BP with 12 months of lifestyle modification.)

 

BP is very high at diagnosis (Systolic BP greater than 180 or diastolic BP greater than 110)

- medication should be started without delay (i.e. at the same time as lifestyle initiatives are introduced.)

 

Systolic BP 140 AND

Diastolic BP  90

(in over 65s)

Systolic BP 130 AND

Diastolic BP  85

(in under 65s)

IMPORTANT

Systolic BP 180 or above

OR

Diastolic BP 110 or above

These are very high blood pressure readings and potentially dangerous in the short (and long) term. People with such high readings require immediate treatment with medication (and investigation).

*Anyone who has an elevated blood pressure or has an increased risk of cardiovascular disease for other reasons should endeavour to reduce their BP by initiating lifestyle measures.

Unless BP is very high, medication should not be commenced unless an elevated BP has been demonstrated on several occasions.

**Overall risk of cardiovascular disease is best assessed using the calculator recommended by the National Heart Foundation: See section on Assessing cardiovascular disease risk

 

Target levels - How far should BP be lowered?

Generally speaking, any lowering of BP is beneficial with respect to reducing cardiovascular disease risk as long as the person does not develop symptoms from low blood pressure and this is why all people at high CVD risk and many at moderate CVD risk are put on blood pressure lowering medication. In practice, BP is not intentionally reduced below 110/70.

Optimally the aim should be to lower blood pressure so that the person moves into the lowest cardiovascukar risk group. (i.e. has a 5 year risk of CVD of less tan 10%). This aim is quite often not achievable because:

Howerever, as stated above, any reduction is beneficial.

It is important to be aware that there can occasionally be problems in lowering BP too much. In some people, especially the elderly, a BP of 140/90 may be too low and cause problems such as dizziness that can lead to injuries from falls. It these circumstances, doctors may quite appropriately aim to maintain BP at a higher level.

Blood pressure normally peaks in the early morning at about 4am to 6am and thus if medication is taken once daily in the morning it will often be wearing off when this this peak occurs. Thus, it is preferable to take once daily medication at night. Taking medication before bed can also have the benefit of minimizing the effect of side effects such as dizziness and fatigue. (Care when getting up from a lying position needs to taken by all people who occasionally get postural dizziness when on blood pressure medication.)

Blood pressure treatment targets

Group

Target BP

Adults over 65 yrs unless in a category below

Less than 140/90

Adults under 65 yrs

Adults with diabetes

Adults with pre-existing vascular disease

Adults with renal impairment

Adults with 0.25g to 1.0g of protein in their urine per day

Less than 130/80

Adults with over 1.0g of protein in their urine per day

Less than 125/75

 

Maintaining good BP control

As stated before, about half of the people taking medication to lower BP do not achieve their target blood pressure levels. Good control is essential if the person is to obtain maximum benefit from taking medication and is especially important if the person’s risk of vascular disease is high. Factors contributing to poor control include the following.

Many of these problems can be overcome by patients discussing potential problems with the doctor when a medication is initially prescribed and by patients mentioning problems that have occurred at future check ups.

Treatment is needed for life and it is important that a person’s BP is regularly monitored by their doctor; usually at least every six months. It is important not to cease or change medication without consulting a doctor.

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Blood pressure medications

Drug groups commonly used as first-line treatments

The choice of medication will depend on numerous factors, including the patient's age, other conditions present, damage already caused by the raised blood pressure, interactions with other medications alreadybeing taken and cost. Selecting the correct blood pressure medication requires a thorough knowledge of the patient and their medical problems and the information below should only be used as a GENERAL GUIDE.

Multiple drug therapy

About 50% to 75% of people with high blood pressure require multiple medications (usually two or three) to achieve their target blood pressure level. Blood pressure is quite difficult to control in some people and, very occasionally, even four medications may be needed. Referred to a specialist should be considered in people whose blood pressure is not easily controlled because:

Some commonly used medication combinations include:

Medication combinations that SHOULD BE AVOIDED

A basic guide to some common blood pressure medications

 

This list provides a basic guide to commonly used blood pressure medications. Each person needs to discus issues regarding medication with their doctor BEFORE commencing treatment.

 

Medication

Use with coexisting conditions

More common side effects

(This list is NOT complete and DOES NOT include rarer side effects.)

Thiazide diuretics

Helps: Heart failure, preventing stroke recurrence.

Contraindications: gout, diabetes, pregnancy

 

Worsens: Gout, diabetes, high cholesterol / triglycerides, impotence.

Should be used with care in people with glucose intolerance or metabolic syndrome as in these people they increase the likelihood of diabetes developing.

Common: Gout, reduced blood potassium, sodium and magnesium, increase in cholesterol, dizziness, weakness, muscle cramps, excessive lowering of blood pressure on standing up.

 

Infrequent: Rash, blurred vision, impotence, worsening diabetes, raised blood calcium, increase in total cholesterol, LDL cholesterol and triglycerides.

Beta blockers**

(This group of drugs is no longer recommended as 'first- line' blood pressure medication as they increase the risk of developing diabetes and beneficial outcomes are less certain.)

Helps; Coronary artery disease (angina or after heart attacks), stable heart failure

 

Contraindications: Asthma, chronic bronchitis and emphysaema, diabetes, heart block, sick sinus syndrome, use with monoamine oxidase inhibitors.

 

Worsens: Asthma, diabetes, impotence, slow heart rate.

Common: Tiredness, breathlessness, impotence, worsening of diabetes and asthma, nausea, diarrhoea, cold hands/feet, excessive slowing of heart rate, excessive lowering of blood pressure, dizziness, insomnia/nightmares, depression, decreased concentration, abnormal vision.

 

Infrequent: Rash, impotence, problems passing urine (sudden in onset), nasal congestion.

Calcium channel blockers

Helps: Angina (not after heart attacks due to risk of exacerbating any heart failure problems)

Contraindications:  Verapamil (heart failure and heart block), Felodipine (pregnancy)

 

Worsens: Heart failure, slow heart rate.

Headache, flushing, lower leg swelling, worsening of heart failure, swollen gums, rash, headache, slow heart rate (verapamil, diltiazem), constipation (esp verapamil)

Angiotensin

Converting

Enzyme (ACE) inhibitors

Helps: Heart failure, helps prevent having a second heart attack or stroke, diabetic kidney disease / other renal impairment*

Contraindications:  Pregnancy, high blood potassium

 

Worsens: Renal artery stenosis (narrowing of arteries supplying kidneys)

Common: Cough, excessive lowering of blood pressure, headache, fatigue, nausea, dizziness, increased blood potassium levels

Can worsen impaired kidney function when it is caused by renal artery disease*

 

Infrequent: Allergic swelling, rash, itching, palpitations, chest pains, flushing, vomiting, anorexia, dry mouth, hoarseness, muscle cramps, abnormal dreams, raised liver blood tests.

Angiotensin-II-receptor antagonists

Helps: Heart failure, helps prevent having a second heart attack or stroke, diabetic kidney disease / other renal impairment*

 

Worsens: Renal artery stenosis (narrowing of arteries supplying kidneys)

Rarely cough, allergic swelling, low blood pressure. Increased blood potassium levels

Can worsen impaired kidney function when it is caused by renal artery disease*

* People with significant renal artery disease (blockage) should not take this medication. (Undiagnosed renal artery disease should be suspected in people with a history of other vascular disease such as heart attacks or strokes or in people whose kidney function worsens when they are put on this medication.)

 

** There is evidence that beta blockers are not as effective as the other medications mentioned above at lowering stroke and heart attack rates when used as a first line blood pressure medication. A recent Cochrane review (2007) states that "The available evidence does not support the use of beta-blockers as first-line drugs in the treatment of hypertension. This conclusion is based on the relatively weak effect of beta-blockers to reduce stroke and the absence of an effect on coronary heart disease when compared to placebo or no treatment. More importantly, it is based on the trend towards worse outcomes in comparison with calcium-channel blockers, renin-angiotensin system inhibitors, and thiazide diuretics. Most of the evidence for these conclusions comes from trials where atenolol (Tenormin) was the beta-blocker used (75% of beta-blocker participants in this review). However, it is not known at present whether beta-blockers have differential effects on younger and elderly patients or whether there are differences between the different sub-types of beta-blockers."  For people who have stable, well-controlled blood pressure who are already taking a beta-blocker, it is probably reasonable to continue their medication regimen unchanged.

Importantly, beta-blockers have been shown to be very beneficial when used in people with heart failure or in those who have had a heart attack and are appropriate to use in many such patiets (but not all). See your doctor.

Monitoring people with high blood pressure

All people with high blood pressure need regular monitoring.  This will vary greatly according to the severity of the hypertension, which medications are being taken, complications already caused by the disease etc. At a minimum it should include:

Who needs specialist care for treatment of their blood pressure?

The following people with high blood pressure need to see a specialist doctor regarding the management of their blood pressure. In most cases this means seeing a heart or kidney specialist, although in country areas where these specialists are not available, referral to general physician is recommended.

 

Additional information

Blood pressure home monitors website 
www.dableducational.org/

Salt Matters (a web site and publication regarding salt)
Beard TC. Salt Matters: A consumer guide. Lothian Books, Melbourne; 2004
www.saltmatters.org

 

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