Angiotensin II-receptor blockers are called 'safe' drugs - safer than ACE inhibitors. Notably, they don't cause persistent coughing, a very common side-effect of the ACE drugs (Clin Ther, 2002; 24: 126-38).
However, these drugs have a coterie of their own problems, including increased blood potassium levels and rapid heart beat, both of which can make a weak heart worse. Potassium is vital as it helps to control heart rhythm.
The most worrying side-effect of irbesartan is a severe drop in blood pressure - which is more likely to occur if your body's supply of water is diminished. So patients taking diuretics should be especially wary of using this class of drugs as well.
It can also cause headaches, dizziness, muscle pain, indigestion, nausea, diarrhoea and weakness. At least 9 per cent of patients have upper respiratory tract infections. Any type of angiotensin drugs should never be taken by pregnant women as they can cause illness or death in the fetus or newborn.
Another strange but common side-effect is the tendency to have minor injuries, mostly related to physical activity, such as muscle or joint sprains. Other symptoms may be heart attack, hypertension, angina, cardiac murmurs or arrhythmias, cardiorespiratory arrest and - guess what? - heart failure.