It is not clear how a diuretic actually decreases urine volume in these patients. They have a rapid oral, IV, and IM absoprtion. There is a diuretic effect within minutes which persists for 1-3 hours. They can produce hypokalemia and metabolic alkalosis. Aldosterone antagonists are usually given with other, more potent, diuretics for their effect of potassium sparing.
Hyperkalemia is a possible side effect.
Xanthines include caffeine, theobromine, and theophylline which is a bronchodilator. Xanthines act to increase cardiac output which increases RBF and GFR resulting in a modest loss of Na, Cl, and water. Additionally a direct tubular action is suspected as their effect persists after RBF and GFR return to normal. Drugs which inhibit the secretion or action of ADH causing a state of nephrogenic diabetes insipidus, include water, narcotics, anesthetics, alcohol, and corticosteroids. The most common side effects of diuretics include fluid depletion which may result in hypotension and prerenal azotemia and potassium depletion which may result in skeletal and smooth muscle weakness and cardiac arrhythmia.