Etidronate Disodium

A to Z Drug Facts

 Action Inhibits normal and abnormal bone resorption; reduces bone formation.

 Indications Treatment of symptomatic Paget disease; prevention and treatment of heterotopic ossification; treatment of hypercalcemia of malignancy.

Treatment of postmenopausal osteoporosis.

 Contraindications Hypersensitivity to biphosphonates; patients with class Dc and higher renal functional impairment (serum creatinine greater than 5 mg/dL).

 Route/Dosage

Paget Disease

Adults: Initial treatment: PO 5 to 10 mg/kg/day (not to exceed 6 mo) or 11 to 20 mg/kg/day (not to exceed 3 mo). Reserve doses greater than 10 mg/kg/day for specific situations. Retreatment: Initiate only after etidronate-free period of at least 90 days and if there is evidence of active disease.

Heterotopic Ossification from Spinal Cord Injury

Adults: PO 20 mg/kg/day for 2 wk followed by 10 mg/kg/day for 10 wk; total treatment period is 12 wk.

Heterotopic Ossification Complicating Total Hip Replacement

Adults: PO 20 mg/kg/day for 1 mo preoperatively followed by 20 mg/kg/day for 3 mo postoperatively.

Hypercalcemia

Adults: IV 7.5 mg/kg/day for 3 successive days given by slow infusion (over a period of at least 2 hr). Retreatment may be needed; wait at least 7 days between courses. Adjust dose for renal impairment. Regimen of oral etidronate (20 mg/kg/day for 30 days) may be started after last infusion.

 Interactions None well documented.

 Lab Test Interferences

Calcium supplements, antacids, foods: Products containing calcium and other multi-valent cations interfere with etidronate absorption.

 Adverse Reactions

EENT: Metallic or altered taste; loss of taste. GI: Diarrhea; nausea; constipation; stomatitis; diarrhea in enterocolitis patients. GU: Abnormal elevations of serum creatinine and BUN; mild to moderate abnormalities in renal function. OTHER: Hypersensitivity (eg, angioedema, urticaria, rash, pruritus); increased or recurrent bone pain in Paget disease; hypocalcemia; fractures with excessive doses; convulsions; hypophosphatemia; hypomagnesemia.

 Precautions

Pregnancy: Category C. Lactation: Undetermined. Children: Safety and efficacy not established. Paget disease: Response may be slow and may continue for months after treatment has been discontinued. Dosage must not be prematurely increased or treatment prematurely reinitiated until patient has had at least 90-day etidronate-free interval. GI disorders: Use this drug with caution in patients with active upper GI problems such as dysphagia (difficulty swallowing); symptomatic esophageal diseases; gastritis; duodenitis or ulcers.

 Administration/Storage

• Have patient take drug on empty stomach 2 hr before meals.
• Administer oral medication as a single dose. If GI upset occurs, dose may be divided.
• To maximize absorption of drug, have patient avoid food high in calcium (eg, milk and milk products), vitamins with mineral supplements and antacids high in metals within 2 hr of dosing.
• Dilute daily IV dose in at least 250 mL of sterile normal saline.
• Slow IV infusion is important. Infuse diluted dose over 2 hr or more.
• Store diluted dose at room temperature no longer than 48 hr.
• Store IV medication away from excessive heat.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies. Note any hypersensitivity to biphosphonates.
• Record dates of any previous treatments with etidronate.
• Treatment of hypocalcemia includes IV calcium administration.
• Monitor serum calcium, phosphate, potassium, BUN, and creatinine.
• Monitor renal status throughout treatment.

 Patient/Family Education

• Instruct patient to avoid eating 2 hr before and 2 hr after taking medication because absorption of drug is reduced by food.
• Advise patient to avoid vitamins, mineral supplements, and antacids that are high in metals, especially calcium, iron, magnesium, and aluminum.
• Instruct patient to maintain adequate intake of foods containing calcium and vitamin D within 2 hr of taking etidronate.
• Inform patient of transient effect of metallic or altered taste or loss of taste.
• Tell patient to report the following symptoms to health care provider: rash, respiratory difficulty, GI upset, visual disturbances, jaundice.
• Instruct patient not to take any OTC medications without consulting the health care provider.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts