Effects of hydrochlorothiazide and amiloride on salt taste and excretion (intake)

The effects of hydrochlorothiazide (HCTZ) and amiloride on salt excretion (intake) and taste were examined in 73 normotensive adults (aged 18 to 56) who were randomly assigned to receive 50 mg/day of HCTZ (n = 24), 5 mg twice daily of amiloride (n = 24) or placebo (n = 25) for 8 weeks. Two and three week placebo periods preceded and followed active treatment, respectively. Relative to baseline, significant increases in sodium excretion (intake) of 31%, 53% and 30% were observed in subjects receiving HCTZ after 2, 4 and 8 weeks of treatment, respectively. An identical follow-up study with 16 subjects replicated the sodium excretion (intake) findings, but failed to reveal the source of the extra dietary sodium. Doubling the dose of amiloride in 11 additional subjects led to higher aldosterone excretion relative to thiazide-treated subjects, but did not increase salt excretion (intake) over a four week period. Only amiloride-treated subjects displayed significant increases in salt taste sensitivity. The increased sodium intake in HCTZ-treated patients may partially offset the desired effects of therapy and exacerbate potassium wasting.