Morbus diureticus in the elderly: epidemic overuse of a widely applied group of drugs.

Diuretics (thiazides, loop diuretics) are established as treatments of common diseases: arterial hypertension, heart failure, and renal disease. In aging societies, their prevalence sharply rises with age. Thus, diuretic efficacy and safety need to be considered in the elderly as main consumers. Diuretics expose several disadvantages with particular relevance for the elderly. The most acknowledged side effects concern electrolyte disturbances. Hypokalemia (up to 8%) may not only precipitate cardiac arrhythmias and related sudden death but also adynamia by muscular weakness. Hyponatremia (up to 17%) may contribute to confusion, delirium, and irreversible brain damage adding to age-related dementia. Thiazides are the antihypertensive drugs with the strongest diabetogenic activity. In heart failure treatment, overdosing of diuretics is common, as doses often reflect requirements for acute recompensation, which is two- to threefold the requirement of that in maintenance therapy. Trial data demonstrate a positive correlation between mortality and diuretic use/dose, which may also be related to volume contraction, related ACE-inhibitor intolerance, renal impairment, and venous thromboembolism. Combining loop and thiazide diuretics may be indicated for severe cardiac or renal failure, but it is also excessively used in less severe stages, causing an even more severe threat to patients; thiazides are often added unintentionally if overlooked in combination pills. Diuretics may be used to treat peripheral "edema" in obese patients, patients on calcium antagonists, or those with venous thrombotic disease. Here they are not indicated and may even induce edema. In statistics on adverse drug reactions leading to hospitalization, diuretics are among the 5 leading drug classes. Misleading interpretations of clinical trials and their low cost have pushed them into the front position of hypertension treatment. Here, side effects, including the urge of voiding, lead to the lowest adherence rate among first-line antihypertensives. It is proposed to term the syndrome of inappropriate diuretic application "morbus diureticus." It should be diagnosed by history taking, force assessment (timed-up-and-go, chair-rise tests), clinical hydration assessment, and laboratory tests (electrolytes, creatinine). In heart failure, dose reductions/step-down from loop to thiazide diuretics should be tested routinely at 3- to 6-month intervals. In hypertension treatment, diuretics should be third in line if control by RAS inhibitors and long-acting dihydropyridine calcium antagonists is insufficient. If symptoms improve after diuretic step-down (including improved tolerance to RAS inhibitors or renal function), this diagnosis may also be made "ex juvantibus."