Alendronate 35 mg Once Weekly: Incorrect Dosing for Osteoporosis Treatment
Alendronate 35 mg once weekly is the prevention dose, not the treatment dose—if this patient has established osteoporosis requiring treatment, the correct regimen is 70 mg once weekly. 1, 2, 3
Correct Dosing Based on Clinical Indication
For Treatment of Established Osteoporosis
- Alendronate 70 mg once weekly is the standard treatment dose for postmenopausal women and men with confirmed osteoporosis (T-score ≤ -2.5 or prior fragility fracture) 1, 2, 3
- Alternative daily dosing is 10 mg daily, but weekly dosing offers superior convenience and potentially better adherence 4, 5
- The 70 mg weekly dose is therapeutically equivalent to 10 mg daily, producing similar BMD increases of 5-7% at the lumbar spine over 1-2 years 5, 6
For Prevention of Osteoporosis
- Alendronate 35 mg once weekly is appropriate only for prevention in postmenopausal women without established osteoporosis (osteopenia or normal BMD with risk factors) 1, 2
- Alternative prevention dose is 5 mg daily 1, 2
Essential Concurrent Supplementation
All patients on alendronate must receive adequate calcium and vitamin D supplementation regardless of dose: 1, 3
- Calcium: 1,000-1,200 mg daily 1, 3
- Vitamin D: 800-1,000 IU daily 1, 3
- Check serum 25(OH)D levels before starting therapy; target ≥30 ng/mL 1
- If 25(OH)D <30 ng/mL, give ergocalciferol 50,000 IU weekly for 8 weeks, then recheck 1
Critical Contraindications to Verify
Before continuing any alendronate dose, confirm the patient does NOT have: 1, 2, 3
- GFR <35 mL/min/1.73 m² (absolute contraindication) 1, 2, 3
- Esophageal abnormalities that delay emptying 1, 3
- Inability to stand or sit upright for at least 30 minutes 1, 3
- Hypocalcemia (must be corrected before starting) 1, 3
Duration of Therapy and Monitoring
- Reassess need for continued therapy after 3-5 years of treatment 1, 3
- Patients at low fracture risk should be considered for drug holiday after 5 years, while high-risk patients may benefit from longer duration 1
- Monitor for rare but serious adverse effects: osteonecrosis of the jaw (<1-28 per 100,000 person-years) and atypical femoral fractures (3.0-9.8 per 100,000 patient-years) 1, 3
Proper Administration Instructions
To minimize esophageal irritation: 4
- Take upon arising with 6-8 oz plain water only
- Remain upright (sitting or standing) for at least 30 minutes
- Take at least 30 minutes before first food, beverage, or other medication of the day
- Do not lie down until after eating first food of the day
Clinical Decision Algorithm
If this patient has established osteoporosis (T-score ≤ -2.5 or prior fragility fracture): Change to alendronate 70 mg once weekly 1, 2
If this patient is only at risk for osteoporosis but does not have it (osteopenia, T-score > -2.5, no fractures): Continue alendronate 35 mg once weekly 1, 2
If uncertain about diagnosis: Obtain DXA scan of lumbar spine, femoral neck, and total hip to confirm osteoporosis before determining appropriate dose 1