Incidence and spectrum of electrolyte disturbances in cisplatin based chemotherapy

Abstract

Background: Cisplatin, one of the most commonly used chemotherapeutic agents, has electrolyte imbalances as one of its most important adverse effects. We conducted this study to characterize the spectrum of its electrolyte abnormalities. Methods: In this observational study, all patients who received chemotherapy containing cisplatin either as single agent or in combination of not more than 2 drugs were included. After baseline investigations, serum electrolytes were recorded, before each cycle of chemotherapy. The incidence and grade of electrolyte abnormalities were analyzed Median dose and cycle at which each of the electrolyte abnormality first occurred was analyzed with Kaplan Meir survival analysis. Results: The most common individual abnormality was hypomagnesaemia, which was seen in 91.8% of patients, followed by hyponatremia 88.2%. Hypocalcaemia 70.6% and hypokalemia 27.1%. The median dose of Cisplatin at which half of the patients had hyponatremia (critical dose) was 195mg and occurred in cycle 2  while the critical dose for potassium was 560mg which occurred in cycle 7. Similarly critical dose and cycle for calcium and magnesium were 240mg at cycle 3 and 160mg at cycle 2 respectively. Majority of electrolyte abnormalities were grade 1 for all the four electrolytes. Grade 3 (15.3%) and Grade 4 (2.4%) was seen predominantly for sodium. There were no grade 3 or 4 hypomagnesaemia. Conclusions: Cisplatin chemotherapy is associated with hypomagnesaemia in a highly significant percentage of patients. Incidence increases with increase in cumulative dose of cisplatin.  Frank clinical manifestations associated with this abnormality are rare.