Severe hyponatremia caused by hyperglycaemia due to interferon alpha therapy in advanced renal cell carcinoma

Electrolyte Disorders Induced by Antineoplastic Drugs

The use of antineoplastic drugs has a central role in treatment of patients affected by cancer but is often associated with numerous electrolyte derangements which, in many cases, could represent life-threatening conditions. In fact, while several anti-cancer agents can interfere with kidney function leading to acute kidney injury, proteinuria, and hypertension, in many cases alterations of electrolyte tubular handling and water balance occur. This review summarizes the mechanisms underlying the disturbances of sodium, potassium, magnesium, calcium, and phosphate metabolism during anti-cancer treatment. Platinum compounds are associated with sodium, potassium, and magnesium derangements while alkylating agents and Vinca alkaloids with hyponatremia due to syndrome of inappropriate antidiuretic hormone secretion (SIADH). Novel anti-neoplastic agents, such as targeted therapies (monoclonal antibodies, tyrosine kinase inhibitors, immunomodulators, mammalian target of rapamycin), can induce SIADH-related hyponatremia and, less frequently, urinary sodium loss. The blockade of epidermal growth factor receptor (EGFR) by anti-EGFR antibodies can result in clinically significant magnesium and potassium losses. Finally, the tumor lysis syndrome is associated with hyperphosphatemia, hypocalcemia and hyperkalemia, all of which represent serious complications of chemotherapy. Thus, clinicians should be aware of these side effects of antineoplastic drugs, in order to set out preventive measures and start appropriate treatments.

Probable boceprevir-induced hyponatremia in a patient with chronic hepatitis C

PURPOSE

A probable case of severe drug-induced hyponatremia associated with boceprevir use is reported.

SUMMARY

A 55-year-old woman was started on boceprevir (800 mg orally thrice daily) during week 5 of triple therapy for chronic hepatitis C. Her serum sodium concentration the morning before starting boceprevir use was 140 mmol/L. After the fourth dose of boceprevir, the patient developed progressive dizziness leading to eventual loss of consciousness. She was taken to the emergency department (ED), where her serum sodium concentration was measured as 126 mmol/L; boceprevir use was temporarily discontinued. The patient's symptoms improved with infusion of 0.9% sodium chloride injection, and she was discharged home the same day. After resuming boceprevir use that evening, the woman developed extreme dizziness and headache upon awakening the next morning. On her return to the ED later that day, she had a serum sodium value of 134 mmol/L and was admitted to the hospital for monitoring and evaluation. Over the next three days, her symptoms improved with additional infusion therapy and discontinuation of boceprevir. The patient continued to receive dual therapy (peginterferon alfa-2a and ribavirin) without further documented serum sodium instability. Using the adverse drug reaction probability scale of Naranjo et al., the case was assigned a score of 5, indicating a probable reaction to boceprevir.

CONCLUSION

Soon after initiating boceprevir use as part of hepatitis C triple therapy, a woman required hospitalization for probable drug-induced hyponatremia, which resolved with discontinuation of the medication.