What are the weekly dosing instructions for Fosamax (alendronate) for osteoporosis?

Weekly Dosing Instructions for Fosamax (Alendronate)

The recommended dose of Fosamax (alendronate) for treating osteoporosis is 70 mg once weekly, which should be taken with plain water at least 30 minutes before the first food, beverage, or medication of the day, and the patient must remain upright for at least 30 minutes after taking it. 1

Proper Administration Technique

• Fosamax must be taken first thing in the morning with 6-8 ounces (180-240 mL) of plain water only (not mineral water, coffee, tea, or juice) 1
• The tablet should be swallowed whole and not crushed, chewed, or allowed to dissolve in the mouth to avoid potential esophageal irritation 1
• The patient must remain upright (sitting or standing) for at least 30 minutes after taking the medication to reduce the risk of esophageal adverse events 2, 1
• No food, beverages, or other medications should be consumed for at least 30 minutes after taking Fosamax 1
• If a dose is missed, the patient should take one tablet on the morning after they remember and then return to taking one tablet once a week on their originally chosen day 1

Dosing Options

• For treatment of established osteoporosis in postmenopausal women and men: 70 mg once weekly 3, 1
• For prevention of osteoporosis in postmenopausal women: 35 mg once weekly 3, 2
• Alternative formulation: Fosamax Plus D (alendronate/cholecalciferol) 70 mg plus 2,800 IU or 5,600 IU once weekly 2

Clinical Considerations and Contraindications

• Alendronate is contraindicated in patients with:

  • Abnormalities of the esophagus that delay esophageal emptying 2
  • Inability to stand or sit upright for at least 30 minutes 2
  • Hypocalcemia 2
  • Renal impairment with GFR < 35 ml/min/1.73 m² 3, 2
  • Hypersensitivity to any component of the product 2

• Weekly dosing has been shown to be therapeutically equivalent to daily dosing while offering greater convenience and potentially improved adherence 4, 5

Monitoring and Duration of Therapy

• Bone mineral density (BMD) increases are evident as early as three months and continue throughout treatment 1
• The optimal duration of therapy is not definitively established, but there appears to be a trend toward interrupting therapy after five to ten years due to concerns about rare adverse effects with long-term use 2

Potential Adverse Events

• The most common adverse events are related to the upper gastrointestinal tract, including abdominal pain, nausea, dyspepsia, and acid regurgitation 6
• Once-weekly dosing may actually have better gastrointestinal tolerability compared to daily dosing 5, 7
• Discontinuing therapy abruptly without considering the potential for rebound bone loss is a clinical pitfall to avoid 3

The weekly dosing regimen of alendronate provides patients with a more convenient, therapeutically equivalent alternative to daily dosing, which may enhance compliance and long-term persistence with therapy 5.