Symptomatic hypocalcaemia after treatment with zoledronic acid in a patient with multiple myeloma

A case of severe, irreversible hypocalcemia after one dose of pamidronate administered for hypercalcemia of malignancy

This is a case report of a patient who developed severe, irreversible hypocalcemia after receiving one dose of pamidronate 90 mg for hypercalcemia of malignancy. Hypocalcemia is a known risk of bisphosphonate treatments, but the incidence of severe hypocalcemia is rare, and the risk factors are well established. However, in the treatment of hypercalcemia of malignancy, the treatment objective is to reduce the elevated serum calcium level, and the bisphosphonate is usually given as one time dose only. The potential for developing severe hypocalcemia may not be considered a significant concern in this setting compared to the setting of the treatment of bone metastasis, where the baseline serum calcium level is not elevated and the bisphosphonate is administered at a regular interval of every three to four weeks. Furthermore, there is unawareness of prevalence of vitamin D deficiency in cancer patients, especially in those with advanced cancer, which may lead to inadvertent, severe hypocalcemia from bisphosphonate treatment. The objective of this case report is to bring awareness to the risk of severe hypocalcemia in patients with hypercalcemia of malignancy and the high prevalence of unrecognized vitamin D deficiency in cancer patients.

Zoledronic Acid for Treatment of Low Bone Mineral Density in Patients with Beta Thalassemia Major

To determine the efficacy of zoledronic acid (ZA) in thalassemia major associated low bone mineral density. Prospective, open label, single arm trial. Bone mineral density (BMD) at lumbar, hip and forearm region were performed at baseline and after 1 year of therapy. Initial, 9 patients received a first dose of 4 mg. Due to severe adverse effects, further doses for these patients and all new recruited patients were 1 mg once every 3 months for 4 doses. All patients were receiving 500 mg of calcium carbonate twice daily and 0.25 μg alfacalcidol once daily before and during the entire study period. Dual energy X-ray absoptiometry was performed at baseline and after 1 year. Twenty-seven patients with transfusion dependent thalassemia with a median age 19.5 year (15-38 years) were eligible for ZA treatment. Seven patients had bony pains. Four patients developed grade 4 hypocalcemia (3 developed tetany) and 2 developed infusion related toxicity with initial dose of 4 mg. One mg dose was well tolerated. At the end of 1 year, bone pains had completely resolved. There was significant increase in BMD at lumbar (p = 0.002) and forearm regions (p = 0.04) and intertrochantric area (p = 0.041). The % change in BMD at 1 year was +3.7 ± 3.2%. ZA is an efficacious agent in treatment of low BMD in these patients. ZA produces significant adverse reactions at 4 mg dose but 1 mg dose is well tolerated and is efficacious.

Hypercalcaemia and hypocalcaemia: finding the balance

Calcium metabolism in cancer and hypercalcaemia of malignancy

The balance between bone formation and resorption may be disrupted in patients with cancer, leading either to increased bone resorption, calcium release, and possibly hypercalcaemia, or to increased bone formation, sequestration of calcium, and possibly hypocalcaemia. In adults, hypercalcaemia of malignancy is most common in patients with tumours that produce factors that induce osteoclast activation and enhance bone resorption. Impaired renal function and increased renal tubular calcium resorption may further affect calcium levels.

Treatment of hypercalcaemia of malignancy

Inhibitors of bone resorption, first the bisphosphonates and, later, denosumab, have been shown to be effective in hypercalcaemia treatment. Bisphosphonates (which are administered intravenously) are approved for hypercalcaemia of malignancy and are the current mainstay of treatment, whereas denosumab (which is administered subcutaneously) may offer an option for patients who do not respond to bisphosphonates or suffer from renal insufficiency.

Hypocalcaemia: treatment and prevention

Hypocalcaemia is most common in patients with prostate cancer and osteoblastic bone metastases, but can occur in patients with a variety of tumour types who are receiving inhibitors of bone resorption. While patients often respond to calcium and vitamin D supplementation, prevention should be the aim; at-risk patients should be identified before starting treatment with inhibitors of bone resorption, be closely monitored during at least the first few months of treatment, and receive concomitant calcium and vitamin D supplementation unless hypercalcaemia is present.

Conclusion

Both hypercalcaemia and hypocalcaemia can be serious if left untreated. It is therefore important that patients with cancer are closely monitored and receive adequate prevention and treatment measures to maintain normal blood calcium levels.

Garcinia Cambogia-Induced Acute Hepatitis; Varenicline-Induced Parkinsonism; Resistant Hypocalcemia After Zoledronic Acid Administration; Zonisamide-Induced Acute Kidney Injury; Psychosis Associated with Guanfacine

The purpose of this feature is to heighten awareness of specific adverse drug reactions (ADRs), discuss methods of prevention, and promote reporting of ADRs to the US Food and Drug Administration's (FDA's) Med Watch program (800-FDA-1088). If you have reported an interesting, preventable ADR to Med Watch, please consider sharing the account with our readers. Write to Dr. Mancano at ISMP, 200 Lakeside Drive, Suite 200, Horsham, PA 19044 (phone: 215-707-4936; e-mail: mmancano@temple.edu). Your report will be published anonymously unless otherwise requested. This feature is provided by the Institute for Safe Medication Practices (ISMP) in cooperation with the FDA's Med Watch program and Temple University School of Pharmacy. ISMP is an FDA Med Watch partner.

Severe resistant hypocalcemia in multiple myeloma after zoledronic acid administration: a case report

Introduction

Hypercalcemia is one of the most common metabolic abnormalities encountered in any form of malignancy. Hypocalcemia, however, is a rare manifestation, especially in cancers with bone involvement. Here we present a case of hypocalcemia in a patient with multiple myeloma that was refractory to treatment.

Case presentation

A 73-year-old African American woman recently diagnosed with multiple myeloma, presented with a 2-day history of fever, vomiting and hypocalcemia. Ten days prior to admission she received zoledronic acid, Velcade^® (bortezomib), Revlimid^® (lenalidomide) and dexamethasone. Treatment was started with intravenous antibiotics and calcium gluconate boluses. After 24 hours of treatment her calcium level became undetectable (<5mg/dL). Continuous intravenous calcium gluconate infusions in addition to boluses were started. She remained persistently hypocalcemic and eventually developed tonic–clonic seizures. Vitamin D levels were found to be low and intravenous paricalcitol was initiated, which improved her calcium level.

Conclusions

Underlying vitamin D deficiency can precipitate severe hypocalcemia in patients with multiple myeloma receiving bisphosphonates. This warrants baseline screening for vitamin D deficiency in these patients.

Risk factors for symptomatic hypocalcaemia complicating treatment with zoledronic acid

BACKGROUND

The bisphosphonate zoledronic acid is commonly prescribed to prevent skeletal complications in patients with multiple myeloma or metastatic cancer. Although symptomatic hypocalcaemia is a potential risk of treatment, it has been thought to be uncommon.

AIMS

After seeing several episodes of symptomatic hypocalcaemia following zoledronic acid administration, we undertook a review to determine the incidence of this complication in our population and to attempt to identify risk factors.

METHODS

We reviewed the records of all patients receiving zoledronic acid in two teaching hospitals over a 2-year period. Findings collected included the indication for treatment, whether dosing was adjusted for creatinine clearance, coadministered medications, serum chemistries and clinical course.

RESULTS

Of 120 patients who received a total of 546 zoledronic acid infusions, hypocalcaemia developed related to 55 infusions (10%) in 42 patients (35%). Symptomatic hypocalcaemia requiring i.v. supplementation occurred in 10 patients (8%), in spite of appropriate dose adjustment for creatinine clearance and despite prophylactic administration of oral calcium and vitamin D. More patients who became hypocalcaemic developed impairment of creatinine clearance during zoledronic acid treatment than in the group that remained normocalcaemic. Hypomagnesaemia was found in all patients who developed hypocalcaemia who had serum magnesium measured.

CONCLUSIONS

Hypocalcaemia was common in our patient group following zoledronic acid treatment. Because of the prolonged elimination half-life of this agent (146 h), renal impairment occurring during a number of days after administration may increase risk. Hypomagnesaemia may further increase risk by blunting compensatory increase in parathyroid hormone secretion.

Management of the adverse effects associated with intravenous bisphosphonates

Intravenous bisphosphonates are widely used to treat hypercalcemia and to reduce skeletal-related morbidity among cancer patients. However, serious complications, generally occurring in less than 2% of patients participated in phase III clinical trials, including acute systemic inflammatory reaction, ocular inflammation, renal failure, nephrotic syndrome, electrolyte imbalance, and osteonecrosis of the maxilla and mandible have all been increasingly reported. Yet, strategies to deal with these complications are becoming clear. Acute systemic inflammatory reaction is often self-limited and becomes less intense during subsequent treatments. For patients who develop ocular symptoms, prompt ophthalmologic evaluation is crucial to determine the safety of a subsequent bisphosphonate therapy. Patients who receive long-term pamidronate should be evaluated at intervals for early sign of nephritic syndrome as timely cessation of the agent may result in a full recovery. To reduce the risk of severe electrolyte abnormalities, particularly hypocalcemia, correcting any pre-treatment electrolyte abnormality and supplementing vitamin D and calcium may be helpful. Finally, to reduce the risk of osteonecrosis of the maxilla and mandible, obtaining a full dental evaluation before treatment and avoidance of invasive dental procedures is suggested. The three commonly used intravenous bisphosphonates (pamidronate, zoledronic acid, and ibandronate), are generally safe; ibandronate has to date been the least reported to be associated with renal side effects. As clinical indications of intravenous bisphosphonates continue to expand, prescribing clinicians should be familiar with these possible adverse effects and discuss them with patients before commencing or continuing on therapy.