Dr. Keld Per Kjeldsen
In heart failure loop diuretics are used to relieve symptoms of congestion. Care should be taken to avoid serious side effects such as dehydration and electrolyte disturbances. Since the effect on mortality is unclear, loop diuretics should probably be reduced to the minimum when there are no longer symptoms of congestion.The problem, however, is how to determine optimum dose. In addition to clinical judgment, the hope is that new imaging modalities and biomarkers may become helpful.In hypertension, thiazides and thiazide-like diuretics are used for monotherapy in light hypertension, and in combination in severe hypertension. Also here, care should be taken to avoid serious side effects such as hypokalemia. In monotherapy, blood pressure is reduced by around 10 mmHg.However, a subsequent decrease in plasma-potassium may increase blood pressure of the same order of magnitude. Thus, in monotherapy it may be considered to shift to other antihypertensives, or in combination therapy it may be considered to discontinue diuretics.Avoiding hypokalemia is one of the major challenges when using diuretics. Here, increased dietary potassium intake, reduced diuretic dose, discontinuation of diuretics, potassium supplementation and aldosterone-antagonists should be considered.Moreover in the RALES and EPHESUS trials these drugs have been shown to significantly reduce mortality in severe heart failure. Also here care should be taken to avoid serious side effects such as hyperkalemia. This is especially the case in renal failure where dosage should be reduced or the drug discontinued. In all patients on these drugs, kidney function and plasma-potassium should be measured regularly. However, it should be kept in mind that moderate hypokalemia generally seems more dangerous - causing arrhythmia and sudden cardiac death - than moderate hyperkalemia. Indications are that potassium-binding resins may become helpful in the treatment with aldosterone antagonists.
Time for reappraisal of diuretics?
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