Animal studies have demonstrated the following mechanism of action: Alendronate shows selective localization at the cellular level in bone, specifically beneath osteoclasts, where these cells عادة attach to the bone surface. Alendronate inhibits osteoclast activity, leading to an increase in bone mass.

Studies in rats using radiolabeled alendronate have shown that its localization on osteoclast surfaces is ten times greater than on osteoblasts.

Continuous administration of alendronate is required to ensure inhibition of osteoclasts on newly formed resorption surfaces.

• Hypersensitivity to alendronate or any of the components of the product.
• Esophageal disorders that delay esophageal emptying (e.g., stricture, achalasia).
• Inability to stand or sit upright for at least 30 minutes after taking the dose.
• Hypocalcemia.
• Severe renal impairment (creatinine clearance < 35 mL/min). 

• Calcium and vitamin D deficiencies should be corrected before starting treatment.
• May cause esophageal irritation or ulceration if not taken properly.
• Caution is advised in patients with a history of esophageal or gastric disorders.
• Long-term use may lead to atypical femoral fractures or osteonecrosis of the jaw.
• Dental evaluation is recommended before starting treatment if dental problems exist.
• Bone density and kidney function should be monitored periodically during treatment. 

• Calcium, antacids, iron, and magnesium: reduce alendronate absorption; they should be taken at least 30 minutes apart from alendronate.
• Nonsteroidal anti-inflammatory drugs (NSAIDs): may increase the risk of esophageal and gastric irritation.
• Corticosteroids: concurrent use may increase the risk of jaw osteonecrosis. 

1. قد يؤدي إلى: نقص كالسيوم الدم، نقص فوسفات الدم، اضطرابات هضمية مثل غثيان، إقياء، حرقة، التهاب المريء أو المعدة.
2. المعالجة:
   • إعطاء الحليب أو مضادات الحموضة المحتوية على الكالسيوم لتقليل امتصاص الدواء الزائد.
   • تجنب إحداث الإقياء بسبب خطر تهيج المريء.
   • إبقاء المريض في وضعية منتصبة.
   • معالجة داعمة وأعراضية حسب الحاجة.

• FDA classification: Category C.