Chemotherapy Agent Causing Hypocalcemia
Mithramycin (option d) is the chemotherapy agent that causes hypocalcemia as a side effect.
Mechanism of Hypocalcemia with Mithramycin
- Mithramycin (also known as plicamycin) directly inhibits bone resorption, which can lead to decreased calcium release from bone and subsequent hypocalcemia 1
- This agent is known to increase parathyroid hormone-mediated osteoclast activation and increase bone turnover, contributing to hypocalcemia 1
Other Chemotherapy Agents and Calcium Metabolism
- Cyclophosphamide (option a) is not associated with hypocalcemia as a primary side effect 1
- Vincristine (option b) primarily causes neurotoxicity rather than electrolyte disturbances like hypocalcemia 1
- Methotrexate (option c) can cause various side effects but is not specifically associated with hypocalcemia 1
- Adriamycin (option e) is not known to cause significant hypocalcemia 1
Clinical Presentation of Hypocalcemia
- Symptoms of hypocalcemia depend on severity and can include neuromuscular irritability, tetany, and seizures in acute cases 2, 3
- Chronic hypocalcemia may present with more subtle manifestations including mental changes (weakness, fatigue, irritability) and skin changes 4
- In severe cases, hypocalcemia can lead to cardiac complications including congestive heart failure 5
Monitoring and Management of Drug-Induced Hypocalcemia
- Serum calcium levels should be monitored before and during treatment with agents known to cause hypocalcemia 6
- For patients receiving mithramycin, baseline and regular monitoring of calcium, vitamin D, and renal function is essential 6, 2
- Calcium supplementation (500-1000 mg/day) and vitamin D supplementation are recommended for prevention and treatment of drug-induced hypocalcemia 6
Other Medications Associated with Hypocalcemia
- Bisphosphonates (such as zoledronic acid, pamidronate) are well-known to cause hypocalcemia through inhibition of osteoclast activity 1
- Denosumab has a higher risk of hypocalcemia (13%) compared to zoledronic acid (6%) 1, 6
- Aminoglycosides can occasionally cause hypocalcemia, though this is not their primary side effect 7
Prevention of Complications
- Baseline assessment should include serum calcium, phosphate, vitamin D, parathyroid hormone, and renal function before initiating agents that may cause hypocalcemia 6
- Adequate calcium intake (1000-1200 mg/day) through diet or supplements is recommended to prevent hypocalcemia in patients receiving at-risk medications 6
- Vitamin D supplementation should be administered alongside calcium to optimize calcium absorption 6