Electronic alerts for preventing hyperkalaemia during potassium-increasing drug-drug-interactions (DDIs) are often overridden due to their low specificity. Treatments of 76,467 inpatients were retrospectively analysed to establish more specific alerts. Alerting concepts for identifying DDIs that induced hyperkalaemia (serum potassium ≥5.5 mEq/l were compared. The positive predictive value (PPV) of alerts was 2.9% if they were triggered at onset of each potassium-increasing DDI. The PPV increased to 5.1% if alerts at onset were suppressed for serum potassium levels of <4.0 mEq/l. The PPV rose to 24.2% with a novel approach, triggering alerts whenever an elevated potassium level of >4.8 mEq/l was detected at onset or during the entire DDI period. Thus, triggering DDI alerts based on periodically monitored potassium levels may improve specificity of alerts and thereby reduce alert fatigue.