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Haemodynamic effects of treatment and withdrawal of spironolactone in essential hypertension
Insights
Spironolactone (50 mg b.i.d.) caused minor systemic and renal circulation adjustments in essential hypertension patients. Despite significant changes in body weight, plasma volume, and hormone levels, key cardiovascular and renal function markers remained largely stable.
Area of Science:
- Nephrology
- Cardiology
- Endocrinology
Background:
- Essential hypertension management often involves diuretics like spironolactone.
- Understanding spironolactone's systemic and renal effects is crucial for optimizing treatment.
- Hormonal and volume status changes are key considerations in antihypertensive therapy.
Purpose of the Study:
- To investigate the effects of spironolactone (50 mg b.i.d.) on systemic and renal hemodynamics in essential hypertension.
- To assess changes in plasma volume, body weight, and the renin-angiotensin-aldosterone system.
- To evaluate the impact of spironolactone withdrawal on these parameters.
Main Methods:
- Two groups of hypertensive patients were studied.
- Measurements included effective renal plasma flow (ERPF), cardiac index (CI), plasma volume (PV), body weight (BW), mean arterial blood pressure (MAP), and hormonal levels (PRA, PA).
- Data collected during treatment and after drug cessation.
Main Results:
- Spironolactone treatment led to decreased body weight (3.5%) and plasma volume (in 9/10 patients), with significant increases in plasma renin activity (PRA) and plasma aldosterone (PA).
- Mean arterial blood pressure (MAP) decreased in most patients, associated with changes in cardiac index (CI) or total peripheral resistance index (TPRI).
- ERPF, blood urea nitrogen (Ur+), and serum creatinine (Cr) remained statistically unchanged during treatment and after withdrawal.
Conclusions:
- Low-dose spironolactone (50 mg b.i.d.) induces consistent alterations in body weight, plasma volume, and the renin-aldosterone system.
- However, it results in only minor adjustments to systemic and renal circulation in essential hypertension.
- These findings highlight a dissociation between hormonal/volume changes and major hemodynamic effects at this dosage.
Abstract:
The effect of spironolactone (50 mg b.i.d.) in essential hypertension was studied by measurement of effective renal plasma flow (ERPF), blood urea nitrogen (Ur+), serum creatinine (Cr), cardiac index (CI), plasma volume (PV), body weight (BW), mean arterial blood pressure (MAP), total peripheral resistance index (TPRI), plasma renin activity (PRA) and plasma aldosterone (PA) in two groups of patients. Ten cases had determinations before, after 5 weeks and 4 months of treatment; fourteen cases who had been treated at an average of 18 months, had measurements while on treatment and 5 weeks after cessation of the drug. Among the ten patients ERPF fell in six and increased in four patients during treatment, but was statistically unchanged in the total group. Ur + and Cr were also unchanged by treatment. ERPF was unchanged after withdrawal of the drug. During treatment BW decreased 3.5%, PV decreased in nine and increased in one patient, while PRA and PA increased 426% and 202%, respectively. After cessation of the aldosterone blockade, BW increased 1.9%, PV 10.5% while PRA and PA fell 60% and 48.9%, respectively. MAP fell in eight out of ten patients during treatment. This fall was associated with a fall in CI or TPRI, or both. After withdrawal of the drug, MAP increased in nine and decreased in five of the patients. The data shows that this dosage of spironolactone gave minor adjustments of the systemic and renal circulation in spite of the consistent changes in BW, PV, PRA and PA.