Zoledronate

Definition

Zoledronate is also known as Zometa. It is a treatment for hypercalcemia (high levels of calcium in the blood) caused by tumors. New laboratory evidence suggests that, in addition, zoledronate may have direct anticancer effects.

Purpose

Tumor-induced hypercalcemia is also known as hyper-calcemia of malignancy. Tumor-induced hypercalcemia may be caused by a tumor spreading to and causing breakdown of bone, or by chemicals released from some tumors. The result is high levels of calcium in the blood. High levels of calcium may cause changes in mental status, constipation, and kidney damage.

Zoledronate is being investigated as a treatment for bone metastases. Bone metastases may develop if cells from breast, lung, or other cancers are transplanted to bone by the disease process. Bone metastasis may cause pain, compression of the nerves of the spine, and bone fractures. Other drugs in the same class as zoledronate are used to prevent pain or fractures in people with bone metastases. Zoledronate is being studied for this use as well. In addition, these drugs (the class of bisphosphonates ) are being studied to see if they prevent the development of bone metastases in the first place.

Description

Zoledronate is one of a group of medicines known as bisphosphonates. Bisphosphonates prevent bone destruction by inhibiting the action of osteoclasts, cells that break down bone. As of 2001, zoledronate is one of the most potent bisphosphonates in use.

Recommended dosage

As of 2001, a definitive recommendation for dosage levels has not been made. One preliminary suggestion is that 2-4 milligrams of zoledronic acid may be given by injection. Zoledronate may be given intravenously over a short time (five to fifteen minutes for example). This might represent an advantage over other drugs in the bisphospho-nate class. The frequency of administration of zoledronate for hypercalcemia depends on the calcium blood level.

Side effects

The most common side effects due to zoledronate that have been reported to date are fever , low blood concentration of phosphate, and low blood calcium (not low enough to cause symptoms). Overall, it appears to be well tolerated.

Bob Kirsch

KEY TERMS

Bisphosphonates

—Bisphosphonates are a class of drugs that inhibit the action of osteoclasts—the cells that dissolve or break down bone.

Bone metastases

—The spread of tumor cells from the primary site of origin to bone. Bone metastases from breast cancer, for example, represent breast cancer cells that have invaded bone. They are not the same as bone cancer cells that originate in bone.

Hypercalcemia of malignancy

—Also called tumor-induced hypercalcemia; high levels of calcium in the blood from the dissolving of bone, either directly by cancer cells or indirectly by chemicals released from cancer cells.