Alendronate Dosing for Osteoporosis
For treating established osteoporosis, alendronate 70 mg once weekly is the recommended dose, which is therapeutically equivalent to 10 mg daily while offering superior convenience and adherence. 1, 2
Standard Treatment Dosing
Alendronate 70 mg once weekly is the first-line dosing regimen for osteoporosis treatment in postmenopausal women and men, providing continuous inhibition of bone resorption despite weekly administration 1, 2, 3
The alternative daily dosing option is 10 mg daily for treatment, though weekly dosing is preferred due to better patient compliance 1, 2
For combination therapy, alendronate/cholecalciferol (Fosamax Plus D) 70 mg plus 2,800 IU or 5,600 IU vitamin D once weekly is recommended 2
Prevention Dosing
For prevention of osteoporosis in postmenopausal women, alendronate 35 mg once weekly is the recommended dose 1, 2
Special Populations
Renal Impairment
- Alendronate is contraindicated in patients with GFR < 35 mL/min/1.73 m² according to renal safety guidelines 1, 2
Cancer Treatment-Induced Bone Loss
Alendronate 70 mg once weekly is effective for patients with cancer treatment-induced bone loss, including those on androgen deprivation therapy 4, 1
For men with prostate cancer on ADT, alendronate increased bone mineral density of the hip and spine by 2.3% and 5.1%, respectively, after 12 months 4
Men with Osteoporosis
Essential Concurrent Supplementation
All patients must receive adequate calcium (1,000-1,200 mg daily) and vitamin D (800-1,000 IU daily) to optimize therapeutic outcomes and prevent hypocalcemia 4, 2
Check serum 25(OH)D levels before starting therapy; target level is ≥30 ng/mL 2
For vitamin D deficiency (25(OH)D <30 ng/mL), give ergocalciferol 50,000 IU weekly for 8 weeks, then recheck 2
Duration of Therapy
Consider drug holidays or dose reduction after 5 years of continuous therapy due to concerns about rare adverse effects (atypical femoral fractures, osteonecrosis of the jaw) while fracture protection may persist 2
The optimal duration is not definitively established, but there is a trend toward interrupting therapy after 5-10 years 2
Contraindications
Abnormalities of the esophagus that delay esophageal emptying 2
Inability to stand or sit upright for at least 30 minutes 2
Hypocalcemia (must be corrected before initiating therapy) 2
Hypersensitivity to any component 2
Critical Administration Instructions
Must be taken in the fasting state with plain water (not mineral water) at least 30 minutes before consuming food or beverages 6
Patient must remain upright (standing or sitting) for at least 30 minutes after administration to reduce esophageal irritation risk 2
Clinical Advantages of Weekly Dosing
86.4% of patients prefer once-weekly dosing over daily dosing due to convenience 7
Weekly dosing achieves better long-term compliance compared to daily administration 7
Therapeutic equivalence to daily dosing is maintained because bone resorption by osteoclasts requires 2-3 weeks for completion, and alendronate remains at active bone remodeling sites for sustained periods 6, 3