High Blood Pressure: Natural Self-help for Hypertension, including 60 recipes

At present, six classes of drug are available to lower high blood pressure:

thiazide diuretics

beta-blockers

alpha-blockers

calcium channel blockers

ACE inhibitors

angiotensin-II receptor antagonists.

If a single drug is not effective, other anti-hypertensive drugs may be added, usually at intervals of at least four weeks, until good control of BP is achieved. Where hypertension is relatively mild (systolic BP less than 160mmHg, and diastolic less than 100mmHg), drugs may be substituted rather than used together.

Thiazide Diuretics

Thiazide diuretics (e.g. bendrofluazide, hydrochlorothiazide) are generally used as a first-line treatment in the elderly, or are combined with other anti-hypertensive drugs (e.g. a beta-blocker or ACE inhibitor) to boost their action in younger patients.

They lower blood pressure by increasing loss of salts through the kidneys into the urine. This tends to draw fluid out of the circulation, causes mild dilation of small arteries and lowers arteriolar resistance. The diuretics act within an hour or two of being given and are usually taken in the morning so you do not have to get up at night to pass water. When you first start taking the tablets, you may notice that you have to pass water more frequently than usual for the first few days;, then this effect tends to disappear as dilation of the arterioles occurs. Only low doses of hiazide diuretic are needed to bring your diastolic BP down by around 5 mmHg – higher doses have no further effect on BP and are more likely to cause side effects such as salt imbalances.

They should not be used by people with diabetes or with sodium, potassium or calcium imbalances, severe kidney or liver problems, active gout or Addison’s disease.

Beta-blockers

The way beta-blockers lower blood pressure is not fully understood but is thought to result from a combination of actions in which they:

alter the way nerve signals cause some blood vessels to dilate or constrict

slow the heart rate to around 60 beats per minute

reduce the force of contraction of the heart

decrease the workload of the heart and cardiac output

lower secretion of a kidney hormone, renin

reduce sensitivity of blood pressure sensors (baroreceptors)

block stress hormone (adrenaline) receptors

have some effects on the brain.

In general, beta-blockers are used as a first-line treatment in young people with hypertension and in people who have coronary heart disease. Because they also affect receptors in the lungs, they should not be used in people with asthma as they may trigger an asthma attack. Beta-blockers have been shown to significantly reduce the risk of having a second heart attack and may prolong life in high-risk individuals.

Beta-blockers should not be withdrawn suddenly, but must be tailed off slowly so that rebound high blood pressure (or angina) does not occur.

Alpha-blockers

Alpha-blockers (e.g. doxazosin, indoramin, prazosin, terazosin) lower blood pressure by dilating both arteries and veins. They are particularly helpful for older males who have both high blood pressure and problems associated with benign enlargement of the prostate gland. They sometimes cause a rapid fall in blood pressure after the first dose so treatment should be started with caution – usually at night so that if low blood pressure does occur, this is after you have retired to bed.

If taking Indoramin, you should avoid alcohol as it boosts alcohol absorption.

Calcium Channel Blockers

Calcium channel blockers (e.g. diltiazem, felodipine, isradipine, lacidipine, nicardipine, nifedipine) work by:

blocking the transport of calcium ions through cell membranes

relaxing muscles in arterial walls and reducing arterial spasm

dilating peripheral veins to encourage pooling of blood

dilating peripheral veins to encourage pooling of blood

reducing the force of contraction of the heart.

Treatment must not be stopped suddenly, but should be tailed off slowly to prevent rebound angina. Verapamil is slightly different from the others in the way it works, and should not be used together with a beta-blocker.

ACE Inhibitors

ACE inhibitor drugs are so-named because they block formation of Angiotensin Converting Enzyme (ACE). This in turn prevents formation of a substance called angiotensin II – a powerful constrictor of blood vessels – leading to dilation of both small arteries and veins. This reduces total peripheral resistance and arterial blood pressure. ACE inhibitors also increase blood flow to the kidneys, so more fluid and sodium is lost as urine. They are usually considered for treating hypertension when thiazides diuretics or beta-blockers are contraindicated, not tolerated, or fail to control high blood pressure.

They can cause a sudden fall in BP on giving the first dose, especially in people who are taking diuretics or who are dehydrated. Where possible, diuretic treatment is therefore usually stopped a few days before ACE inhibitor treatment is started. For some, the first dose is best taken at night on retiring to bed. Kidney function and salt balance should be checked before treatment is started. ACE inhibitors may be less effective in people of Afro-Caribbean descent unless combined with a thiazide diuretic.

Angiotensin-II Receptor Antagonists

These drugs (e.g. losartan, valsartan, candesartan) are similar to the ACE inhibitors except that instead of inhibiting angiotensin-converting enzyme, they block angiotensin-II to produce similar effects. This dilates blood vessels, stimulates kidney function and may also have a direct action on the brain to reduce drinking and increase urine output. At present, they are mainly used in people who develop a persistent dry cough as a troublesome side-effect of the ACE inhibitors as these particular drugs do not produce this problem.

Other Drugs

Occasionally, drugs from the above groups may not be sufficient or suitable for treating an individual case of high blood pressure. Two other drugs are sometimes used: hydralazine or methyldopa.

Hydralazine is a vasodilator that lowers blood pressure by relaxing arteries and increasing their diameter. When used to treat hypertension, it is usually combined with a beta-blocker and thiazide diuretic to stop the heart rate and cardiac output from increasing and to avoid fluid retention. It may cause a very rapid drop in blood pressure.

Methyldopa used to be the most popular drug for treating high blood pressure, and may still be taken by elderly patients who started on it many years ago. It lowers blood pressure by acting on the brain to trigger nerve actions that reduce heart output, urine production and arteriolar constriction. Methyldopa is often used together with a diuretic. It may cause a rapid fall in blood pressure, especially in the elderly.

Your doctor may also suggest taking low-dose aspirin or taking drugs to lower blood cholesterol levels if necessary.

IS ANTI-HYPERTENSIVE TREATMENT FOR LIFE?

Once drug treatment is started for high blood pressure, it is often for life. However, if you don’t have any complications from your high blood pressure and you have managed to make diet and lifestyle changes that naturally bring your blood pressure down, it may be possible to reduce your tablet dose or to withdraw it altogether. However, you should never alter your medication or stop it suddenly yourself. If your doctor decides to withdraw your treatment, this is usually done slowly in a step-wise fashion to prevent a sudden rebound hypertension. You will be followed up closely over a long period of time, as, in some cases, BP starts to creep back up again after six months, a year or more.

IF YOU SHOULD FORGET TO TAKE YOUR MEDICATION

If you do forget to take your treatment occasionally, it is unlikely that you will come to any harm. If you forget your tablets on a regular basis, however, you may run into problems.

If your treatment is only a few hours late, take it as soon as you remember.