ClassIndications
- Treatment and prevention of osteoporosis in women
- Paget's disease of bone
- To reduce hypercalcemia in tumor-induced bone disease
Administration/Absorption- Mean oral bioavailability of alendronate in women was 0.7%
Dosage
- Prophylaxis of osteoporosis in women: 5–10 mg daily or 35–70 mg weekly
- Paget's Disease: 40 mg daily for 6 months
Distribution- 78% protein bound
- VOD 28 L
Mechanism- Based partly on its affinity for hydroxyapatite, which is part of the
mineral matrix of bone
- Also targets farnesyl pyrophosphate
(FPP) synthase
- Acts as a analogue of isoprenoid diphosphate lipids, thereby
inhibiting FPP synthase
- An enzyme in the mevalonate pathway
- Inhibition
of this enzyme in osteoclasts prevents the biosynthesis of isoprenoid
lipids (FPP and GGPP)
- Essential for the post-translational
farnesylation and geranylgeranylation of small GTPase signalling
proteins
- This activity inhibits osteoclast activity and reduces bone
resorption and turnover
Excretion- There is no evidence that alendronate is metabolized in humans or animals
- Approximately 50% excreted in the urine within
72 hours
Side effects- Can damage the esophagus
- By toxicity from the
medication itself
- Also by nonspecific irritation secondary to contact
between the pill and the esophageal mucosa
- Rash
- Osteonecrosis of the Jaw
- Rare instances of auditory hallucinations and visual disturbances
Interactions
- Milk, diet, and drugs containing high amounts of calcium, magnesium or aluminium decrease absorption
- The combination of NSAIDs and alendronate may increase the risk of gastric ulcers
Contraindications
- Acute inflammations of the gastrointestinal tract (esophagitis, gastritis, ulcerations)
- Clinically manifest osteomalacia
- Certain malformations and malfunctions of the esophagus (strictures, achalasia)
- Inability to stand, walk, or sit for 30 minutes after oral administration
- Renal impairment with a creatinine clearance below 30ml/min
- Hypersensitivity to alendronate or another ingredient
- Hypocalcemia
- Pregnancy and breastfeeding
- Patients below 18 yrs. of age, as no clinical data exists
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