Hyperkalemia, an excess of potassium in the body, can occur when the two types of drugs are combined.

FORBES: Pfizer's Heart Failure Flop

Specifically, Tekturna was associated with an increased risk of non-fatal stroke, renal complications, hyperkalemia, and hypotension .

FORBES: ALTITUDE Study of Aliskiren Terminated Early by Novartis

But in yesterday's issue of The New England Journal of Medicine, researchers published a study showing that patients on spironolactone were more likely to die from hyperkalemia.

FORBES: Pfizer's Heart Failure Flop

The action was based on the recommendation of the independent Data Monitoring Committee (DMC), after it found an increased risk for non-fatal stroke, renal complications, hyperkalemia, and hypotension in patients taking aliskiren after 18-24 months.

FORBES: ALTITUDE Study of Aliskiren Terminated Early by Novartis