Alendronate
FOSAMAX
What it isBone-binding FPPS inhibitor that suppresses osteoclasts; first-line oral treatment for osteoporosis.
Why this oneHip and vertebral fracture evidence, generic cost and a weekly tablet make it the benchmark oral bisphosphonate.
What limits itTake fasting with water and stay upright to prevent esophagitis. Avoid severe renal impairment; long use rarely injures the jaw or femur.
FDA-approved for
- osteoporosis (1995)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Osteoporosis treatment (postmenopausal women) | 10 mg QD or 70 mg once weekly | |||
| Osteoporosis prevention (postmenopausal women) | 5 mg QD or 35 mg once weekly | |||
| Increase bone mass in men | 10 mg QD or 70 mg once weekly | |||
| Glucocorticoid-induced osteoporosis | 5 mg QD (10 mg QD if postmenopausal, not on estrogen) | |||
| Paget's disease of bone | 40 mg QD for 6 months |
Renal Not recommended if CrCl <35 mL/min; no adjustment for CrCl 35-60 mL/min
Hepatic No dosage adjustment necessary
Instructions
- Swallow whole with 6-8 oz plain water upon arising, at least 30 minutes before first food/drink/medication of the day
- Do not lie down for at least 30 minutes and until after first food; do not take at bedtime
- Missed weekly dose: take the next morning; do not take two doses on the same day
- Ensure adequate calcium and vitamin D intake
Contraindications
- Inability to stand or sit upright for at least 30 minutes
- Hypocalcemia
- Esophageal abnormalities that delay esophageal emptying (e.g., stricture, achalasia)
Cautions
- Upper GI adverse reactions (esophagitis, ulcers, erosions) — follow dosing instructions; discontinue if new/worsening symptoms
- Hypocalcemia must be corrected before starting
- Severe bone, joint, and/or muscle pain
- Osteonecrosis of the jaw
- Atypical low-energy femoral shaft fractures — evaluate new thigh/groin pain
- Not recommended if CrCl <35 mL/min
Adverse reactions
- Abdominal pain, acid regurgitation, constipation, diarrhea, dyspepsia, musculoskeletal pain, nausea
Pregnancy Insufficient data; discontinue when pregnancy is recognized. Bisphosphonates incorporate into bone with potential for fetal skeletal harm.
Lactation Not known whether alendronate is present in human milk or affects the breastfed infant.
NO BOXED WARNINGS
Principal riskEsophagitis; remain upright for 30 minutes
Cost, est. cash$4–$80/month
Generic entry2008
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityEsophageal injury and rare osteonecrosis/atypical fracture; administration technique matters.
Mechanism of action: Alendronate ballicule
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