Drug giant AstraZeneca has agreed to buy US firm ZS Pharma in a $2.7 billion (£1.8bn) cash deal.

It will give UK-based AstraZeneca access to a drug that could potentially treat the life-threatening condition hyperkalaemia.

The drug, ZS-9, is currently under regulatory review by the US Food and Drug Administration.

Shareholders in ZS Pharma will receive $90 (£59) per share, which represents a 42 per cent premium compared to Thursday's close price.

AstraZeneca boss Pascal Soriot said: "Hyperkalaemia can be a life-threatening condition for patients with chronic kidney disease and chronic heart failure, however the risk is underappreciated and prevalence is increasing.

"This acquisition complements our strategic focus on cardiovascular and metabolic disease by adding a potential best-in-class treatment to our portfolio of innovative medicines.

"We look forward to welcoming the ZS Pharma team to AstraZeneca.

"Under the terms of the agreement, AstraZeneca will acquire all of the outstanding capital stock of ZS Pharma for 90 dollars per share in an all-cash transaction, or approximately 2.7 billion dollars in aggregate transaction value."

AstraZeneca said the deal would not affect its financial guidance for 2015. On Thursday, the drug giant raised its full-year revenue guidance after stronger-than-expected quarterly sales driven by its key heart treatment drug Brilinta.

AstraZeneca fought off a £69bn takeover bid from US rival Pfizer last year.