[Serum and total body potassium during treatment with chlortalidone and hydrochlorothiazide. Influence of triamterene (author's transl)].

The serum and total body potassium was investigated in 25 patients with non-congestive cardaic failure before and during saluretic treatment. Treatment with triamterene (100 mg/d; n = 10) over a period of 3 weeks led to an increase of serum potassium (from 4.1 +/- 0.65 to 4.7 +/- 0.51 mmol/l) and of total body potassium (by 110 mmol). After treatment with chlortalidon for 7 days (100 mg/d; n = 6) serum potassium concentration decreased from 4.38 "/- 0.37 to 3.30 +/- 0.46 mmol/l (approximately 25%). The total body potassium decreased by 240 mmol (approximately 10%). Continuation of the treatment with a combination of chlortalidon (50 mg/d) and triamterene (150 mg/d) led to correction of the extra- and intracellular potassium loss after 1 to 2 weeks. No significant change of serum and total body potassium was found during and after 6 months of treatment with hydrochlorothiazide (50 mg/d) and triamterene (100 mg/d; n = 9). The results demonstrate the potassium loss which occurs in the early stage of saluretic treatment and show the antikaluretic potency of triamterene.