Generic Name

Ibandronate

Mechanism

• High‑affinity binding to hydroxyapatite crystals in bone, localizing the drug at sites of active resorption.
• Inhibition of farnesyl pyrophosphate synthase in the mevalonate pathway → decreased prenylation of small GTPases essential for osteoclast function.
• Result: ↓ osteoclast activity → ↓ bone resorption, ↑ bone mineral density (BMD), and reduced fracture risk.

Pharmacokinetics

Indications

• Postmenopausal osteoporosis (oral 150 mg weekly).
• Glucocorticoid‑induced osteoporosis (oral 150 mg weekly).
• Paget disease of bone (IV 5 mg monthly, up to 3 years).
• Preventing fractures in high‑risk patients (e.g., bone‑protective indication in breast cancer on aromatase inhibitors).

Contraindications

• Absolute: esophageal or gastric ulcer, impaired esophageal motility, active esophagitis, pregnancy, lactation.
• Renal impairment: eGFR <30 mL/min → contraindicated IV; dose reduction for oral.
• Hypocalcemia (untreated) → monitor Ca⁺²⁺ before initiation.
• Osteonecrosis of the jaw (ONJ): avoid in patients with recent dental surgery or poor oral hygiene.
• Atypical femoral fractures: rare but reported with prolonged use.

Dosing

• Oral: 150 mg once weekly (no more than 5 days apart).
• Take on an empty stomach with 4–8 oz of plain water.
• Remain upright for 30 min; do not eat or drink for 30 min before the next dose.
• IV (Paget disease): 5 mg by slow infusion over 8 min, once monthly for up to 3 years.
• Renal dose adjustment (oral):
• eGFR 30–49 mL/min: 150 mg every 2 weeks.
• eGFR <30 mL/min: avoid; consider alternative bisphosphonate.

Adverse Effects

• GI: dyspepsia, esophagitis, abdominal pain, nausea.
• Musculoskeletal: back pain, arthralgia, myalgia.
• Hypocalcemia → tetany, paresthesia (especially post‑transplant).
• Osteonecrosis of the jaw (rare).
• Atypical femoral fractures (rare).
• Infusion‑related (IV): fever, chills, back pain.

Monitoring

• Baseline: serum Ca⁺²⁺, phosphate, creatinine, eGFR, 24‑h urine calcium.
• Ongoing:
• Calcium & creatinine every 6–12 months (long‑term therapy).
• Bone turnover markers (e.g., CTX) if monitoring efficacy or withdrawal.
• Dental exam before initiating therapy and periodically thereafter.

Clinical Pearls

• Empty‑stomach rule is critical: non‑compliance >30 % of doses leads to 30–50 % loss of efficacy.
• Switching bisphosphonates: for patients on alendronate, switch to ibandronate only after a 1‑month break to avoid overlapping bone‑binding.
• “Bisphosphonate holiday”: consider 1–2 year break after 3–5 years in low‑risk patients; reassess BMD before resuming.
• Paget management: maintain IV 5 mg monthly until ALP normalizes for 1–2 months; then switch to oral for long‑term suppression.
• Renal safety: patients with eGFR 30–49 mL/min should receive oral every‑other‑week dosing, not IV.
• Patient education: emphasize strict hydration, upright posture, and avoidance of large meals immediately before/after dosing to prevent esophagitis.
• Onset of effect: BMD improvements seen after 2–3 years; early benefit reflected by reduced vertebral fracture risk.

*This drug card summarizes key pharmacological facts and practical guidance for using ibandronate in clinical practice.*