ARBs

Angiotensin receptor blockers (or ARBs for short) are a type of medication that is commonly used to treat high blood pressure. They work by blocking the effect of the hormone angiotensin-II on individual cells in your body.

Angiotensin-II increases your blood pressure by making your artery walls contract. This narrows the arteries and gives your blood less space to move in – raising your blood pressure. ARBs reduce the amount of angiotensin-II your kidneys make, allowing your arteries to stay more open and reducing your blood pressure.

Angiotensin-II also stimulates your adrenal glands to produce a hormone that makes the body retain water. This increases the amount of fluid in your body and raises your blood pressure. Angiotensin receptor blockers also reduce the amount of hormone your adrenal glands produce, which lowers the amount of water you retain and helps to lower your blood pressure.

Who should take angiotensin receptor blockers?

Angiotensin receptor blockers (ARBs) are often used as a first choice of treatment for people aged younger than 55 years old who are white or Asian. These people appear to have higher levels of angiotensin-II in their bloodstream. This means that their blood pressure is influenced more strongly by the effects of this hormone, so any medicine that reduces its effect will be most powerful.

Angiotensin receptor blockers (ARBs) work in a similar way to ACE inhibitors – while ARBs stop angiotensin-II from acting on the cells in your body, ACE inhibitors stop your body from making angiotensin-II in the first place. For this reason, ARBs are often given to people who find that ACE inhibitors work well for their blood pressure, but that they develop side-effects from them.

Who should not take angiotensin receptor blockers?

Angiotensin receptor blockers (ARBs) should not be taken if you are pregnant, trying to become pregnant, or breastfeeding, because they may affect your baby's development. Instead your doctor will prescribe one of the other types of blood pressure drug that will not cause any unwanted effects to the baby.

In some older people, and people with kidney disease, the amount of potassium in the blood can be affected by angiotensin receptor blockers (ARBs). If you are taking an ARB you may be asked to have regular blood tests.

People with a kidney condition called renal artery stenosis may also need to be closely monitored if they are taking angiotensin receptor blockers (ARBs).

Angiotensin receptor blockers (ARBs) may also need to be used with caution in those people with certain heart conditions.  Your doctor will advise you if this is the case.

African-Caribbean people, particularly those with an enlarged left side of the heart, may not benefit from taking an angiotensin receptor blocker – in other words, it may not affect their blood pressure and there may be better alternatives.

What are the most common side-effects of angiotensin receptor blockers?

Although angiotensin receptor blockers (ARBs) are often given to people who have side-effects from ACE inhibitors, this does not mean that they cannot have side-effects of their own.

However, angiotensin receptor blockers (ARBs) do have very few side-effects. In many studies they showed the same number of side-effects as the placebo tablet, in other words a tablet that contains no active ingredients.

If you develop side-effects from your medications, your doctor may be able to help by lowering your dose, or by changing your medicine. Do not stop taking any medication without first speaking to your doctor.

Types of angiotensin receptor blocker

Most medications have two names – the generic name (which is the name of the medicine itself) and the brand name (which is the name the medicine is sold under). This means different companies may make and sell the same medicine, but they may sell it with different brand names. The table below lists some angiotensin receptor blocker (ARB) medicines currently used in the UK: