ACE inhibitors
ACE inhibitors are mainly used in the therapy of arterial hypertension, i.e. increased blood pressure. One consequence is based on the inhibition of the renin-angiotensin-aldosterone system (RAAS), which causes less aldosterone to be released. In less than 10% of cases, this causes an increase in serum potassium, i.e. hyperkalemia.
This side effect does not occur in low doses. The following risk factors also increase the probability of excess potassium: pre-existing renal failure, heart failure and advanced age. The parallel intake of non-steroidal anti-inflammatory drugs (NSAIDs) and potassium-sparing diuretics also promotes the occurrence of hyperkalemia.
Alkalosis
Changes in the pH-value have an effect on the potassium concentration. A decreasing, i.e. acidic pH value (= acidosis) causes a redistribution of the ions. The potassium concentration in serum increases.
In the therapy of hyperkalemia, the reverse effect is used to lower the potassium value. The administration of sodium hydrogen carbonate increases the pH value. This creates an alkalosis, which lowers the concentration of potassium in the serum. A side effect of the therapy with sodium hydrogen carbonate is therefore the alkalosis by increasing the pH-value.