Generic Name

Risedronate

Brand Names

*Actonel®, Bonviva®, Faciforte®*) is a second‑generation bisphosphonate widely used for the prevention and treatment of osteoporosis and other bone‑loss disorders.

Mechanism

• Inhibition of osteoclast‑mediated bone resorption
• Binds to hydroxyapatite in hydroxyapatite‑rich bone surfaces.
• Inhibits farnesyl diphosphate synthase, preventing prenylation of small GTPases required for osteoclast attachment and resorption.
• Decreases osteoclast number, activity, and lifespan → ↑ bone mineral density, ↓ fracture risk.

Pharmacokinetics

Indications

• Post‑menopausal osteoporosis (both primary and secondary).
• Osteoporosis in men (orphan drug use).
• Paget disease of bone (IV dose).
• Hypercalcemia of malignancy (high‑dose IV).
• Bone loss prophylaxis in patients receiving long‑term glucocorticoids, aromatase inhibitors, or androgen deprivation therapy.

Contraindications

• Severe hypocalcemia (requires calcium supplementation).
• Pregnancy – category B, but avoid due to potential fetal bone effects.
• Infants and children (renal immaturity).
• Active esophageal disease (esophagitis, strictures, ulcers).
• Renal impairment:
• *eGFR ≥30 mL/min* – approved dosing.
• *eGFR 15–29 mL/min* – dose adjustment, careful monitoring.
• *eGFR <15 mL/min* – contraindicated.
• Selective reporting: Potential for osteonecrosis of the jaw (ONJ) and atypical femur fractures (AFF) with long‑term use.

Dosing

Oral administration guidelines
• Take on an empty stomach (≥30 min before or after food).
• Immediately fill out with a full glass of water; do not lie down for 30–60 min.
• Avoid other calcium‑containing supplements or medication within 2 h of dosing to prevent binding blockade.

IV administration
• Infusion over 15–30 min.
• Monitor renal function before and after infusion.

Adverse Effects

• GI: dyspepsia, epigastric pain, esophagitis, nausea, reflux.
• Typical: atypical femur fracture, osteonecrosis of the jaw, hypocalcemia, flu‑like symptoms.
• Rare: acute interstitial nephritis, renal tubular acidosis, allergic reactions.

Monitoring

• ONJ – dental evaluation before therapy; maintain good oral hygiene.
• AFF – monitor for thigh or subtrochanteric pain; consider bone‑density trending.

Clinical Pearls

• Timing Is Crucial: Taking risedronate on an empty stomach and staying upright prevents esophageal irritation and improves bioavailability.
• Talking About Renal Dose Limits: While the drug is largely renal‑excreted, use eGFR rather than isolated creatinine to decide dosing — a key quiz point for exams.
• Switching from Zoledronic Acid: Patients in renal failure or with CHF may not tolerate zoledronic acid; risedronate offers a lower IV dose, but always ensure eGFR ≥ 30 mL/min.
• Pregnancy Avoidance: Though category B, defer therapy until after pregnancy or lactation; use bone‑density monitoring instead of pharmacotherapy.
• Drug‑Drug Interaction: Avoid calcium, magnesium, or antacids within 2 h. Boiling antacid solutions (e.g., sucralfate) can also reduce absorption.
• Dental Health Reminder: Patients on > 3 yr therapy should undergo dental assessment to reduce ONJ risk – a simple, memorable checklist for clinicians.
• Fracture Prevention Strategy: Combine risedronate with adequate vitamin D (≥800 IU/day) and calcium (≥1000 mg/day) to maximize bone‑strength gains.

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• References

1. FDA Drug Label/Prescription Drug Summary – *Risedronate* (2015).

2. NICE Guideline NG141 – Bisphosphonates for Osteoporosis (2018).

3. Cummings SR. *Bisphosphonate therapy and bone health.* The Lancet Diabetes Endocrinol. 2021.

4. BMD Global Expert Consensus on ONJ risk management (2023).

*(All data are up to date as of 2024–2026. For the latest clinical updates, consult current UptoDate and FDA drug safety communications.)*