The Oslo University study which looked at 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, according to the study published in British medical journal 'The Lancet'.

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", the researchers 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," Elspeth McAusland, of The Stroke Association, was quoted as saying by the Telegraph.

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

However, the researchers 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.