Chlorthalidone: Adverse Reactions

Just like thiazides, chlorthalidone imperatively causes a dose dependent reduction of the plasma potassium levels. With a daily dose of 50 mg, at least 5 to 10% of the treated subjects develop an actual hypokalemia (3.0 mmol/l or less). For people with existing ECG alterations a hypokalemia represents an increased risk of lethal arrhythmias. Other electrolysis disturbances (hyponatremia, hypomagnesemia, hypercalcemia) are not as frequent. Reduced glucose tolerance, generally asymptomatic hyperuricemia (risk of gout!), increase of low-density lipoproteins, as well as orthostatic hypotension have been observed in more than 5%. Men sometimes complain about impotence.

Exanthema, hematological anomalies, pancreatitis, vasculitis are rare.

Chlorthalidone: Interactions

Like other kaliuretic diuretics, chlorthalidone can increase lithium toxicity and be detrimental to the efficacy of oral antidiabetics: a hypokalemia induced by diuretics increases the digitalis toxicity and antiarrhythmic risk of sotalol. Anti-inflammatory agents reduce the hypotensive effect of chlorthalidone.

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