Serum potassium, calcium and magnesium in patients receiving ESHAP chemotherapy for relapsed lymphomas

Etoposide, methylprednisolone, cytarabine and cisplatin (ESHAP) is one of  the  mostly  widely  used  chemotherapy  regimens  for  patients  with  relapsed lymphomas.  Cisplatin  administration  is  commonly  associated  with  electrolyte imbalance. Careful monitoring of renal function and serum electrolytes is therefore essential in this setting.
Aims:
To review the practice of electrolyte monitoring – potassium (K), calcium (Ca)  and  magnesium  (Mg)  –  in  patients  receiving  ESHAP  and  the  frequency  and severity of abnormalities and their management.
Methods:
Twenty-one consecutive patients received ESHAP. The medical records of 16 patients were retrievable and reviewed retrospectively. Results of serum K, Ca and Mg were collected prior to and after cycles 1, 2 and 3 of ESHAP, if measured.
Results:
Serum K levels prior to every cycle did not show any noticeable change. The means were 4.42, 4.34 and 4.43 mmol/l before cycles 1, 2 and 3, respectively. In  one  patient  hypokalaemia  was  severe,  refractory  and  symptomatic  when preceded  by  hypomagnesaemia.  Serum-adjusted  calcium  levels  showed  only minimal reduction. The means were 2.46, 2.40 and 2.38 mmol/l before cycles 1, 2 and 3 respectively. Mean serum Mg levels prior to every cycle showed progressive reduction; 0.84, 0.75 and 0.67 mmol/l before cycles 1, 2 and 3, respectively. This was  associated  with  a  progressive  increase  in  the  amount  of  required  Mg supplementation. Serum K, Ca and Mg was measured prior to 100%, 67% and 35% of administered cycles, respectively.
Conclusion:
In patients receiving ESHAP, hypokalaemia can occasionally be seen, especially  if  preceded  by  hypomagnesaemia.  Mild  cumulative  hypocalcaemia  is recognised. Hypomagnesaemia is a progressive complication and physicians need be aware of its importance.