Negative potassium balance during beta-blocker treatment of hypertension.

Potassium balance was followed in seven hypertensive patients during treatment with timolol. The patients developed a mean 150 mmol total potassium loss. Serum potassium and body weight were not changed. It is suggested that the changes in total body potassium during timolol treatment may be due to mobilization of potassium from the intracellular space, but, since serum potassium did not rise, timolol may also influence renal handling of potassium.