A Norwegian study of 2,000 stroke patients, who all had high blood pressure, found that more of those treated with the drug candesartan suffered from kidney failure than those who were not given it. more also suffered symptoms due to low blood pressure, such as dizziness.

The academics, from Oslo university, concluded that administering candesartan, which belongs to the family of drugs called angiotensin-receptor blockers, did not give any benefit to the patients “and may actually be harmful”.

Candesartan is sometimes given stroke patients to lower blood pressure, which reduces the chances of another event.

However, they said the differences in harmful outcomes between those given the drug and those not, was not statistically significant.

In addition, the actual numbers who suffered these side effects was small. Only 18 of the candesartan group suffered kidney failure, compared to 13 in the placebo group; while the figures for low blood pressure symptoms were nine and five respectively.

Elspeth McAusland, of the Stroke Association, said: “This research suggests that stroke physicians should avoid using blood pressure lowering medication at this stage, however more research needs to be done in this area.”