What is the recommended treatment and dosage for osteoporosis using Fosamax (alendronate)?

Alendronate (Fosamax) Treatment for Osteoporosis

For osteoporosis treatment, alendronate is recommended at a dose of 70 mg once weekly (preferred) or 10 mg daily, while prevention requires 35 mg once weekly or 5 mg daily, with proper administration on an empty stomach with water and remaining upright for 30 minutes. 1, 2

Indications for Treatment

Alendronate is indicated for:

• Treatment of osteoporosis in postmenopausal women
• Prevention of osteoporosis in postmenopausal women
• Treatment to increase bone mass in men with osteoporosis
• Treatment of glucocorticoid-induced osteoporosis in men and women receiving glucocorticoids equivalent to ≥7.5 mg prednisone daily 2

Dosage Recommendations

Treatment Dosage

• 70 mg once weekly (preferred regimen) OR
• 10 mg daily 1, 2

Prevention Dosage

• 35 mg once weekly OR
• 5 mg daily 1

Administration Instructions

For optimal absorption and to minimize adverse effects:

• Take on an empty stomach after an overnight fast
• Take with a full glass of plain water (6-8 oz)
• Remain upright (sitting or standing) for at least 30 minutes after taking
• Do not lie down until after first food of the day 1

Supplementation Requirements

Patients should receive adequate supplementation alongside alendronate:

• Calcium: 1000-1200 mg daily
• Vitamin D: 600-800 IU daily 1

Efficacy

Alendronate demonstrates significant efficacy in reducing fracture risk:

• Vertebral fractures: reduced by 47-56%
• Hip fractures: reduced by approximately 50%
• All clinical fractures: reduced by approximately 30% 1, 3

For secondary prevention (patients with existing osteoporosis or fractures), alendronate:

• Reduces clinical vertebral fractures by 55% (RR 0.45)
• Reduces non-vertebral fractures by 20% (RR 0.80)
• Reduces hip fractures by 51% (RR 0.49)
• Reduces wrist fractures by 46% (RR 0.54) 3

Risk Assessment and Treatment Decisions

For adults ≥40 years, treatment decisions should be based on fracture risk:

• Very high risk: Prior osteoporotic fracture(s), BMD T-score ≤−3.5, or FRAX 10-year risk of major osteoporotic fracture ≥30% or hip ≥4.5%
• High risk: BMD T-score ≤−2.5 but >−3.5, or FRAX 10-year risk of major osteoporotic fracture ≥20% but <30% or hip ≥3% but <4.5%
• Moderate risk: FRAX 10-year risk of major osteoporotic fracture ≥10% and <20%, hip >1% and <3%, or BMD T-score between −1 and −2.4 4

Monitoring Recommendations

• Bone mineral density (BMD) with vertebral fracture assessment or spinal x-ray every 1-2 years during treatment
• BMD with vertebral fracture assessment or spinal x-ray every 1-2 years after osteoporosis therapy is discontinued 4

Duration of Therapy

• Optimal duration is typically 5 years
• After 5 years, continuation should be reassessed
• Patients at low risk for fracture should be considered for drug discontinuation after 3-5 years of use 1, 2

Adverse Effects

Common adverse effects:

• Upper GI symptoms (abdominal pain, dyspepsia, acid regurgitation)
• Musculoskeletal pain 1

Rare but serious adverse effects:

• Osteonecrosis of the jaw
• Atypical femoral fractures 1, 3

Special Considerations

Contraindications

• Severe renal impairment (creatinine clearance <35 mL/min)
• Hypocalcemia (should be corrected before starting therapy)
• Esophageal abnormalities
• Inability to stand/sit upright for at least 30 minutes
• Hypersensitivity to any component of the product 1

Dental Work

Complete dental work before starting therapy to reduce the risk of osteonecrosis of the jaw 1

Mechanism of Action

Alendronate is a bisphosphonate that:

• Binds to bone hydroxyapatite
• Specifically inhibits osteoclast activity
• Reduces bone resorption without directly affecting bone formation
• Decreases bone turnover and increases bone mass at remodeling sites 2

By following these evidence-based recommendations for alendronate therapy, clinicians can effectively manage osteoporosis while minimizing adverse effects and optimizing patient outcomes.