alendronate sodium
Fosamax

Available forms
Available by prescription only
Tablets: 5 mg, 10 mg, 35 mg, 40 mg, 70 mg

Indications and dosages
 Osteoporosis in postmenopausal women; to increase bone mass in men with osteoporosis. Adults: 10 mg P.O. daily or 70-mg tablet P.O. once weekly taken with water at least 30 minutes before first food, beverage, or medication of the day.
 Prevention of osteoporosis in postmenopausal women. Adults: 5 mg P.O. daily or 35-mg tablet P.O. once weekly taken with water at least 30 minutes before first food, beverage, or medication of the day.
 In conjunction with calcium and vitamin D supplementation in the treatment of corticosteroid-induced osteoporosis. Adults: 5 mg P.O. daily, taken with water at least 30 minutes before first food, beverage, or meal of day. In postmenopausal women not receiving estrogen replacement therapy, dose is 10 mg P.O. daily.
 Paget’s disease of bone. Adults: 40 mg P.O. daily for 6 months taken with water at least 30 minutes before first food, beverage, or medication of the day.

Pharmacodynamics
Antiosteoporotic action: At the cellular level, alendronate suppresses osteoclast activity on newly formed resorption surfaces, which reduces bone turnover. Bone formation exceeds bone resorption at bone remodeling sites and thus leads to progressive gains in bone mass.

Pharmacokinetics
Absorption: Absorbed from the GI tract. Food or beverages can decrease bioavailability significantly.
Distribution: Distributed to soft tissues and then rapidly redistributed to bone or excreted in urine. Protein-binding is about 78%.
Metabolism: Doesn’t appear to be metabolized.
Excretion: Excreted in urine.

Contraindications and precautions
Contraindicated in patients hypersensitive to any component of drug and in patients with hypocalcemia or severe renal insufficiency (creatinine clearance below 35 ml/minute). Use cautiously in patients with active upper GI problems, such as dysphagia, symptomatic esophageal diseases, gastritis, duodenitis, or ulcers, and in patients with mild to moderate renal insufficiency (creatinine clearance between 35 and 60 ml/minute).

Interactions
Drug-drug. Antacids, calcium supplements, and many oral drugs: Interfere with absorption of alendronate. Instruct patient to wait at least 30 minutes after taking alendronate before taking any other oral drugs.
Aspirin, NSAIDs: Increase risk of upper GI adverse reactions with alendronate doses above 10 mg daily. Monitor patient closely.

Adverse reactions
CNS: headache.
GI: altered taste, abdominal pain, nausea, dyspepsia, constipation, diarrhea, flatulence, acid regurgitation, esophageal ulcer, vomiting, dysphagia, abdominal distention, gastritis.
Metabolic: hypocalcemia, hypophosphatemia.
Musculoskeletal: pain.

Effects on lab test results
• May cause a mild decrease in serum calcium and phosphorus levels.

Overdose and treatment
Oral overdose may cause hypocalcemia, hypophosphatemia, and upper GI adverse effects, such as upset stomach, heartburn, esophagitis, gastritis, or ulcer.
 Specific treatment information isn’t available, but consider administration of milk or antacids (to bind alendronate). Dialysis isn’t beneficial.

Special considerations
• Hypocalcemia must be corrected before drug therapy begins. Other disturbances of mineral metabolism (such as vitamin D deficiency) should also be corrected before starting therapy.
• When drug is used to treat osteoporosis in postmenopausal women, disease is confirmed by low bone mass findings on diagnostic studies or history of an osteoporotic fracture.
• Drug is indicated for patients with Paget’s disease who have alkaline phosphatase levels at least twice the upper limit for normal, in those who are symptomatic, or in those at risk for future complications from the disease.
• Monitor patient’s serum calcium and phosphate levels throughout therapy.
• Assess patient for dysphagia, odynophagia, or retrosternal pain.
• Monitor patient’s renal function tests. Manufacturer recommends not using medication in patients with creatinine clearance less than 35 ml/minute.
Breast-feeding patients
• Drug may appear in breast milk; don’t give to breast-feeding women.
Pediatric patients
• Safety and efficacy in children haven’t been established.
Geriatric patients
• Although no overall differences in efficacy or safety were observed in clinical trials between geriatric and younger patients, greater sensitivity of some older people can’t be ruled out. Use cautiously in this age group.

Patient education
 ALERT Advise patient to take drug with a full glass of water and sit upright for 30 minutes to avoid esophageal ulcer formation.
• Stress importance of taking each tablet with a glass of plain water (not mineral water or other beverage) first thing in the morning at least 30 minutes before ingesting food, beverages, or other drugs. Tell patient that waiting longer than 30 minutes improves absorption of drug.
• Tell patient to take supplemental calcium and vitamin D if daily dietary intake is inadequate.
• Inform patient about the benefit of weight-bearing exercises in increasing bone mass and the importance of modifying excessive cigarette smoking and alcohol consumption, if these factors are part of patient’s lifestyle.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use