Class Explorer · Endocrine
Bisphosphonates
Bind hydroxyapatite, are swallowed by osteoclasts as they resorb, and kill them from the inside. Bone formation then outpaces resorption.
Members
Also in this class: Risedronate · Zoledronic acid · Denosumab (different mechanism, same role). Full pages arrive as the library grows.
Compare the members
Alendronate
- Route
- Oral weekly
- Administration rules
- Fasting, plain water, upright 30 minutes
Shared across the class
- Indications
- Osteoporosis · Glucocorticoid-induced osteoporosis · Paget disease · Malignant hypercalcemia and skeletal-related events
- Adverse effects
- Oesophagitis (oral) · Acute phase reaction (intravenous) · Hypocalcemia · Osteonecrosis of the jaw · Atypical femoral fracture
- Contraindications
- Hypocalcemia · Severe renal impairment · Inability to remain upright (oral)
- Monitoring
- Calcium and vitamin D before starting and periodically · Renal function · New thigh or groin pain · Dental status before starting
What makes each agent different
- Oral agents have negligible bioavailability and strict administration rules; the intravenous agents bypass all of that at the cost of an acute phase reaction after the first dose.
- Osteonecrosis of the jaw is rare at osteoporosis doses and much more frequent at the far higher oncology doses, a distinction that causes a great deal of unnecessary alarm.
Correct vitamin D first. Giving a potent antiresorptive to a deficient patient produces symptomatic hypocalcemia.
The skeletal half-life is measured in years, which is what makes a treatment break a real option rather than an interruption.
Last reviewed 2026-08-16 · Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed.