Background Reviewing prescriptions for high-risk patients must be a priority. Because of their cardiac consequences, disorders of potassium blood levels represent a frequently-occurring preventable iatrogenic event.

Purpose The authors decided to analyse the effect of pharmacists' alerts on patients with dyskalaemia, and thus show that their prescriptions must be reviewed with priority.

Materials and methods A prospective study was conducted in 2 medical units (neurology and pneumology) and a surgery department. Prescriptions were daily reviewed for four months with a computerised physician order entry (CPOE) system (Cristal Net). Dyskalaemic patients were identified (hypo/hyperkalaemia defined on biological laboratory limits). Therapeutic problems and pharmacists' alerts were codified according to the French Clinical Pharmacy Society's coding tables (SFPC). Physicians' acceptance rate was evaluated.

Results 873 patients were hospitalised during the study. A total of 3016 prescriptions were reviewed by pharmacists. 159 patients (18%) showed a blood potassium level disorder during their stay and 337 prescriptions were evaluated for these patients. Of these, 103 (31%) required pharmaceutical intervention (PI). 74% of PIs were directly related to kalaemia disorders. The numbers were higher in general surgery with 49% of PIs in dyskalaemic patients. The main causes of PI were: a contraindication (22%), an adverse drug effect (23%) or an overdose (17%). 12 patients left the ward before physicians responded to the PI. For the remaining patients, practitioners accepted 79% of PIs and modified their prescriptions.

Conclusions The results show a higher percentage of PIs in dyskalaemic patients (31%) compared with the results in non-dyskalaemic patients (11%) and literature reviews (<10%). Therefore, it is more likely that prescriptions in dyskalaemic patients will have a problem. The high acceptance of PIs by prescribers shows how important and relevant they are. The consequences of kalaemia disorders can be fatal, particularly among older and/or multi-medicated patients. Dyskalaemic patients' prescriptions should be reviewed by pharmacists with the highest priority.