'In people with high blood pressure the kidneys can retain salt and water, which increases blood pressure levels,' said Athena account director Natalie Bennett.
'Taking a diuretic increases the amount of fluid released from the body through the kidneys and lessens the pressure in the blood vessels.'
Director of UK business Beverley Evans will head up the account, reporting to Sankyo Pharma UK Olmetec brand director Liz Mills.
Athena has worked on other cardiology accounts, including Sanofi Aventis' Plavix, Solvay's Omacor and Menarini's Nebilet.
In December Sankyo Co, Sankyo Pharma UK's parent company, sold 11 over-the-counter drugs in Germany to German firm Stada Arzneimittel AG for £56m.