Alendronate (Alendronic acid) 💊

📚 Related Subjects: | Calcium Physiology | Hypercalcaemia | Bisphosphonates | Osteoporosis | Osteonecrosis of the Jaw

⚠️ Key Safety Notes: Osteonecrosis of the jaw may be seen in cancer patients – always obtain a 🦷 dental assessment before treatment. Atypical femoral fractures are rare but reported with prolonged therapy. 👉 Review risks/benefits after ≥5 years of bisphosphonate use. ✅ Ensure patients are replete with calcium + vitamin D before starting.

📖 About

Always check the BNF link here.

• 💊 Bisphosphonate used in postmenopausal osteoporosis, Paget’s disease, bone metastases, and breast cancer with bone involvement.

⚡ Mechanism of Action

• ⬇️ Inhibits osteoclastic bone resorption, preserving bone density and reducing fracture risk.

🩺 Indications & Administration

• Osteoporosis (postmenopausal, glucocorticoid-induced, male osteoporosis).
• Paget’s disease of bone.
• Bone pain due to metastases (specialist use).
• 📌 Administration rules:
  • Take on an empty stomach, at least 30 minutes before breakfast or other medicines.
  • 💧 Swallow whole with a full glass of water.
  • 🧍‍♂️ Stay upright (sitting or standing) for ≥30 minutes afterwards to prevent oesophageal irritation.

💊 Dose Range (always verify in BNF/datasheet)

⚠️ Interactions

• ⬆️ Risk of GI ulcers with NSAIDs or Aspirin.
• Absorption reduced by calcium/iron supplements, antacids → separate dosing.

🚫 Contraindications

• Achalasia, oesophageal stricture, or motility disorders.
• Other oesophageal abnormalities delaying gastric emptying.
• ❌ Hypocalcaemia.
• Renal impairment: avoid if eGFR < 35 mL/min/1.73m².

💥 Side Effects

• 🤢 GI upset: abdominal pain, dyspepsia, constipation, diarrhoea, flatulence.
• 🩸 Oesophageal ulcer, melaena, dysphagia, distension, acid regurgitation.
• 💪 Musculoskeletal pain, headache.
• ⬇️ Hypocalcaemia and hypophosphataemia.
• 🌡️ Rash, hypersensitivity reactions.
• 🦴 Femoral stress fractures (rare).
• 🦷 Osteonecrosis of the jaw (esp. after dental extraction, cancer patients).

📑 References

• Alendronate in BNF