Hypokalemia drug-induced

Use of a hERG blocker in a patient also taking drugs inducing electrolyte imbalance (e.g. risk of hypokalemia with diuretics) this is a pharmacodynamic interaction... 

Potassium balance The effect of quinidine is enhanced by potassium and reduced if hypokalemia is present. The risk of drug-induced torsade de pointes is increased by concomitant hypokalemia. 

Digoxin susceptible to alteration of gastrointestinal absorption. Digitalis toxicity may be increased by drug-induced electrolyte imbalance (eg, hypokalemia). Digitoxin metabolism inducible. Renal and nonrenal excretion of digoxin susceptible to inhibition. 

Tishler M, Armon S. Nifedipine-induced hypokalemia. Drug Intell Chn Pharm 1986 20(5) 370-1. 

Many drugs may cause hypokalemia by a variety of mechanisms. These mechanisms include intracellular potassium shifting and increased renal or stool losses (Table 50-1). Non-potassium-sparing diuretic administration is the most common cause of drug-induced hypokalemia. Loop and thiazide diuretics inhibit renal sodium reabsorption, which results in increased sodium delivery to the distal tubule. Consequently, hypokalemia develops because the distal... 

Antiarrhythmic drugs that block potassium channels, such as sotalol and quinidine, can cause the polymorphic ventricular tachycardia known as torsades de pointes (see Chapter 34). The abnormal repolarization that leads to polymorphic ventricular tachycardia is potentiated by hypokalemia, and diuretics that produce potassium loss increase the risk of this drug-induced arrhythmia. 

ACE inhibitors do not completely block aldosterone synthesis. Since this steroid hormone is a potent inducer of fibrosis in the heart, specific antagonists, such as spironolactone and eplerenone, have recently been very successfully used in clinical trials in addition to ACE inhibitors to treat congestive heart failure [5]. Formerly, these drugs have only been applied as potassium-saving diuretics in oedematous diseases, hypertension, and hypokalemia as well as in primary hyperaldosteronism. Possible side effects of aldosterone antagonists include hyperkalemia and, in case of spironolactone, which is less specific for the mineralocorticoid receptor than eplerenone, also antiandrogenic and progestational actions. 

Diuretics - Generally initiate therapy with a thiazide or other oral diuretic. Thiazide-type diuretics are drugs of choice hydrochlorothiazide or chlorthalidone are generally preferred. Reserve loop diuretics for selected patients. This therapy alone may control many cases of mild hypertension. Consider treating diuretic-induced hypokalemia (less than 3.5 mEq/L) with potassium supplementation or by adding a potassium-sparing diuretic to therapy. 

Diuretics may induce hypokalemia, which sensitizes the heart to digoxin toxicity and stops the tubular excretion of the drug. Toxicity has gastrointestinal (nausea,... 

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