When to Start Fosamax (Alendronate)
Alendronate should be initiated in patients with a BMD T-score of less than -2.0 or in those with a T-score above -2.0 who have at least two clinical risk factors for fracture. 1
Indications for Starting Alendronate
Based on Bone Mineral Density (BMD)
- Start alendronate in patients with a BMD T-score less than -2.0 1
- Consider alendronate in patients with osteopenia (T-score between -1.0 and -2.5) who have additional risk factors 2, 3
Based on Risk Factors
- Initiate treatment in patients with two or more of the following risk factors, even if T-score is above -2.0: 1
- Age over 65 years
- Current smoking or history of smoking
- Low BMI (<24)
- Family history of hip fracture
- Personal history of fragility fracture after age 50
- Oral glucocorticoid use for more than 6 months
Special Populations
- In cancer patients receiving endocrine treatment (aromatase inhibitors for breast cancer or androgen deprivation therapy for prostate cancer), start alendronate if T-score is less than -2.0 or if patient has two or more risk factors 2, 1
- For patients on glucocorticoid therapy, consider alendronate to prevent bone loss 4
Dosing Recommendations
- For treatment of osteoporosis: 70 mg once weekly (preferred dosing regimen) 5, 6
- For prevention of osteoporosis: 35 mg once weekly or 5 mg daily 5
- Consider combination with vitamin D (Fosamax Plus D: 70 mg alendronate plus 2,800 IU or 5,600 IU vitamin D) for patients with or at risk for vitamin D deficiency 5
Monitoring and Follow-up
- Measure BMD at baseline and repeat after 1-2 years of treatment to assess response 3, 1
- For patients with osteopenia (T-score > -2.0), BMD measurements do not need to be repeated routinely unless baseline T-score is < -2.0 or new risk factors develop 3
- Consider shorter monitoring intervals (1 year) after initiation of therapy or in high-risk patients such as those on glucocorticoid therapy 3
Duration of Therapy
- The optimal duration of bisphosphonate therapy is not definitively established, but consider interrupting therapy after 5-10 years due to concerns about rare adverse effects with long-term use 5
Contraindications and Precautions
- Do not use alendronate in patients with:
- Correct vitamin D deficiency before initiating alendronate, particularly before intravenous bisphosphonate therapy, as vitamin D deficiency may attenuate efficacy and increase risk of hypocalcemia 4
Clinical Pearls and Pitfalls
- Alendronate is considered first-line therapy for osteoporosis treatment due to its established efficacy in reducing fracture risk 5, 7
- Patients must take oral alendronate with a full glass of water at least 30 minutes before consuming food or beverages to ensure proper absorption 6
- Instruct patients to remain upright for at least 30 minutes after taking alendronate to reduce risk of esophageal irritation 4
- Consider dental evaluation before starting therapy, as osteonecrosis of the jaw is a rare but serious complication, particularly in patients requiring dental surgery 4