ALENDRONATE SODIUM (a-len'dro-nate)
Fosamax, Fosamax D (with 2800 IU Vitamin D3) Classifications: bisphosphonate; regulator, bone metabolism; Therapeutic: bone metabolism regulator Prototype: Etidronate Pregnancy Category: C
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Availability
5 mg, 10 mg, 35 mg, 40 mg, 70 mg tablets; 70 mg/75 mL oral solution
Action
A bisphosphonate that inhibits osteoclast-mediated bone resorption. Antiresorption mechanism is thought to be localized
to resorption sites of active bone turnover and to have minimal to no interference with bone mineralization.
Therapeutic Effect
Alendronate decreases bone resorption, thus minimizing loss of bone density.
Uses
Prevention and treatment of osteoporosis in postmenopausal women, Paget's disease. Treatment of glucocorticoid-induced osteoporosis.
Contraindications
Hypersensitivity to alendronate or other bisphosphonates; achalasia, esophageal stricture, severe renal impairment (Clcr <35 mL/min); hypocalcemia; abnormalities; pregnancy (category C); lactation.
Cautious Use
Renal impairment, CHF, hyperphosphatemia, liver disease, fever or infection, active upper GI problems.
Route & Dosage
Treatment of Osteoporosis Adult: PO 10 mg once/d (max: 40 mg/d) or 70 mg q wk
Prevention of Osteoporosis, Treatment of Steroid-induced Osteoporosis Adult: PO 5 mg q.d. or 35 mg q wk
Treatment of Paget's Disease Adult: PO 40 mg once/d for 6 mo
Renal Impairment Clcr <35 mL/min: use not recommended
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Administration
Oral
- Correct hypocalcemia before administering alendronate.
- Administer in the morning at least 30 min before the first food, beverage, or medication. Do not administer within 2 h of
calcium-containing foods, beverages, or medications. At least 30 min should elapse after alendronate dose before taking any
other drugs.
- Oral Solution: Use oral syringe for accurate dosage. Give with at least 60 cc (2 oz) of plain water.
- Tablet: Give with 8 oz of plain water.
- Keep patient sitting up or ambulating for 30 min after taking drug.
- Store according to manufacturer's directions.
Adverse Effects (≥1%)
Endocrine: Hypocalcemia, hypophosphatemia.
GI: Esophageal irritation and
ulceration, nausea, vomiting, abdominal pain, dyspepsia, diarrhea,
constipation, flatulence.
Other: Arthralgias, myalgias, headache, rash.
Interactions
Drug: Ranitidine increases alendronate availability.
Food: Calcium and food (especially dairy products) reduce alendronate absorption.
Pharmacokinetics
Absorption: 0.51% from GI tract (absorption significantly decreased by calcium and food).
Onset: 36 wk.
Duration: 12 wk after discontinuation.
Distribution: Rapid skeletal uptake.
Metabolism: Not metabolized.
Elimination: Up to 50% excreted unchanged in urine.
Half-Life: Up to 10 h.
Nursing Implications
Assessment & Drug Effects
- Lab tests: Monitor albumin-adjusted serum calcium, serum phosphate, serum alkaline phosphatase, fasting and 24 h urinary
calcium, and serum electrolytes. Periodically monitor renal and liver functions.
- Diagnostic test: Bone density scan every 1218 mo.
- Discontinue drug if the Clcr <35 mL/min.
Patient & Family Education
- Review directions for taking drug correctly (see ADMINISTRATION).
- Report fever, especially when accompanied by arthralgia and myalgia.