ETIDRONATE DISODIUM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ETIDRONATE DISODIUM (ETIDRONATE DISODIUM).
Bisphosphonate that inhibits osteoclast-mediated bone resorption by binding to hydroxyapatite crystals in bone, suppressing crystal dissolution and reducing bone turnover.
| Metabolism | Not metabolized; excreted unchanged primarily by the kidney. No known hepatic metabolism. |
| Excretion | Renal: 30-50% of absorbed dose excreted unchanged in urine; biliary/fecal: minimal, with approximately 5% excreted in feces. |
| Half-life | Terminal half-life: 1-6 hours after single dose; prolonged to up to 2 weeks in bone due to slow release from hydroxyapatite. |
| Protein binding | Approximately 50% bound to serum proteins, primarily albumin. |
| Volume of Distribution | 0.3-0.5 L/kg; large distribution due to extensive binding to bone hydroxyapatite. |
| Bioavailability | Oral: 1-10% (dose-dependent, reduced by food). |
| Onset of Action | Oral: 24-48 hours for inhibition of bone resorption; IV: minutes to hours for serum calcium reduction. |
| Duration of Action | Oral: 7-14 days for inhibition of bone resorption; IV: up to 7 days for serum calcium effect. Note: Duration may be prolonged in patients with renal impairment. |
Paget disease: 5-10 mg/kg/day orally, given as a single dose or divided every 12 hours, for up to 6 months; or 300 mg intravenously over at least 2 hours daily for 3 days. Heterotopic ossification: 20 mg/kg/day orally for 2 weeks pre- and 12 weeks post-surgery. Hypercalcemia of malignancy: 7.5 mg/kg intravenously over 4 hours daily for 3-7 days.
| Dosage form | TABLET |
| Renal impairment | GFR >50 mL/min: no adjustment. GFR 30-50 mL/min: reduce dose by 50%. GFR 10-29 mL/min: reduce dose by 75%. GFR <10 mL/min: contraindicated. |
| Liver impairment | No dose adjustment required for hepatic impairment. Not metabolized by liver. |
| Pediatric use | Dysplasia fibrosa polyostotica: 20 mg/kg/day orally for 6 months, then 6-month drug-free interval. Hypercalcemia of malignancy: 5-10 mg/kg intravenously over 4 hours daily for 3 days. Safety and efficacy not established for Paget disease in children. |
| Geriatric use | Start at low end of dosing range. Monitor renal function closely; adjust dose based on creatinine clearance due to age-related decline. Avoid prolonged therapy. Ensure adequate calcium and vitamin D intake. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ETIDRONATE DISODIUM (ETIDRONATE DISODIUM).
| Breastfeeding | Excretion into human milk unknown. M/P ratio not available. Due to potential for bone alteration and hypocalcemia in the nursing infant, discontinue breastfeeding or the drug. Consider risks versus benefits. |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: theoretical risk of skeletal abnormalities due to bisphosphonate incorporation into fetal bone; limited human data. Second and third trimesters: potential for fetal hypocalcemia and skeletal demineralization due to calcium chelation; avoid especially after 20 weeks gestation as it may interfere with fetal bone development. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to etidronate or any bisphosphonate","Hypocalcemia (uncorrected)","Severe renal impairment (CrCl <30 mL/min)","Osteomalacia with impaired bone mineralization","Clinically evident osteomalacia"]
| Precautions | ["Renal impairment: avoid use in severe renal failure (CrCl <30 mL/min). Monitor renal function.","Hypocalcemia: ensure adequate calcium and vitamin D intake.","Osteonecrosis of the jaw: risk with concurrent dental procedures or malignancies.","Atypical femur fractures: consider discontinuation if suspected.","Infusion-related reactions: transient fever, flu-like symptoms with IV use.","Esophageal irritation: oral formulation may cause esophagitis; instruct to take with full glass of water and remain upright."] |
| Food/Dietary | Avoid dairy products (milk, yogurt, cheese), calcium-fortified juices, mineral water, and high-calcium foods (e.g., almonds, leafy greens) for at least 2 hours before and after administration. Do not take with food, especially items high in calcium, iron, magnesium, or aluminum (e.g., antacids). Administration with any food reduces absorption significantly. |
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| Fetal Monitoring | Monitor serum calcium, phosphate, and renal function (BUN, creatinine) periodically. Assess urine calcium:creatinine ratio. Monitor for signs of hypocalcemia (paresthesias, tetany). Ultrasound monitoring of fetal bone mineralization if prolonged use during pregnancy. |
| Fertility Effects | Animal studies: No impairment of fertility in rats at doses up to 2 mg/kg/day. Human data limited. May affect calcium homeostasis, potentially influencing ovulatory cycles. No conclusive evidence of fertility impairment in humans. |
| Clinical Pearls | Monitor serum phosphate and calcium regularly; avoid use in patients with hypocalcemia or vitamin D deficiency. Administer on an empty stomach with plain water (not milk, juice, or mineral water). Do not co-administer with calcium, iron, or magnesium supplements within 2 hours. Use the lowest effective dose for the shortest duration to minimize risk of osteomalacia. In Paget's disease, a rise in alkaline phosphatase may indicate relapse. Contraindicated in patients with significant renal impairment (CrCl <30 mL/min) or during pregnancy/lactation. |
| Patient Advice | Take this medication on an empty stomach, at least 2 hours before or after any food or drink (especially milk, juice, or coffee). · Swallow the tablet with a full glass of plain water only; do not crush or chew. · Avoid calcium supplements, antacids, iron, or magnesium-containing products for at least 2 hours before and after taking etidronate. · Report any new bone pain, muscle cramps, or numbness around the mouth (signs of electrolyte imbalance). · Maintain adequate intake of calcium and vitamin D as directed by your doctor, but time supplements correctly. · Do not take etidronate for longer than prescribed; follow the specific dosing cycle (e.g., 2 weeks on, 11 weeks off). · If you miss a dose, skip it and take the next one at the scheduled time; do not double dose. |