Effect of Licorice and Hydrochlorothiazide on Plasma Potassium

Effect of Licorice and Hydrochlorothiazide on Plasma Potassium

This clinical trial is designed to study the effect of the combination of licorice and hydrochlorothiazide on plasma potassium levels in volunteers. In one arm, 10 healthy volunteers will be given 32 grams of licorice a day together with a 25 mg dose of daily hydrochlorothiazide for 14 days. This combination is compared with 32 grams of licorice a day for 14 days given in the other arm. The study is a randomized, open-label cross-over trial. There is at least a 3-week wash-out between the arms. The hypothesis is that the combination of licorice and hydrochlorothiazide will cause hypokalemia. The main outcome measure is the change in the plasma level of potassium between the arms.

Inclusion Criteria:

• Healthy volunteer
• Age 18-40 years

Exclusion Criteria:

• Any continuous medication
• Any significant disease
• Hypotension or hypertension
• Allergy to licorice or hydrochlorothiazide
• Pregnancy and breast feeding
• Fear of needles and previous difficult blood samplings
• Substance abuse
• Participation in another clinical drug trial within 1 month of enrollment