Carmine

Does age in treating high blood pressure in elderly people make having in this treatment more difficult and is this age group more likely to have side effects from antihypertensive agents than their younger counterparts?

In general, people in their 70s and older tolerate all drugs less well than younger people because their kidneys and livers eliminate drugs less efficiently and their bodies are generally less able to tolerate big changes, including changes in blood pressure. Other concerns are that some elderly people may be more likely to make mistakes in remembering to take their tablets as prescribed and also many have to take other drugs for other health problems, which may cause complicated interactions between different drugs.

On the other hand, elderly people generally respond to blood pressure lowering medications just as well as younger people, perhaps rather more so. They often show a good fall in blood pressure with smaller doses of blood pressure lowering drugs than are required by middle-aged people.

Most commonly used blood pressure lowering drugs seem to be relatively trouble-free and effective for the elderly, particularly thiazide diuretics at low doses, which are almost always the best first choice in this age group, as well as for younger people. Their theoretical drawback is that they tend to make the underlying body chemistry of diabetes worse, but even for elderly people who already have diabetes, the benefits greatly outweigh harmful effects. Angiotensin-converting enzyme inhibitors (ACE inhibitors) also seem to be effective and (so far - in drug terms they are still fairly new) trouble free, except for provoking a dry cough in about a quarter of people who do not have either asthma or heart failure.

The drugs which are best avoided are the alpha adrenergic receptor blockers (alpha blockers), which can cause fainting in the elderly and the drugs acting mainly on the brainstem - methyldopa and clonidine. Elderly people starting on blood pressure lowering medications for the first time are unlikely to be prescribed theses drugs acting mainly on the brainstem, but those who have been on medication for some years may still be taking them, because they were the best drugs available for them when they started their treatment.

Methyldopa commonly causes liver damage in elderly people, often bad enough to cause severe jaundice. As well as making them ill, it can be very difficult to sort out the diagnosis, because blood test results in this condition closely resemble those for other common causes of jaundice such as gallstones, virus infections of the liver and side effects of other drugs. It should be avoided in elderly people and unlike other blood pressure lowering drugs, even people who have taken it for many years without trouble should probably switch to less risky alternative by their late 60s.

Clonidine often causes depression. As elderly people develop severe depression more commonly than younger people do and more frequently go undetected, this drug should be avoided when medication is started for the first time in this age group. People who have taken clonidine for years, staring in middle age, can reasonably continue as they get older, providing they don't have any trouble.

Michael Russell Your Independent guide to Blood Pressure