alendronate sodium trihydrate + colecalciferol; cholecalciferol: clinical use

Prescribing considerations

• Confirm the licensed population and ability to follow administration instructions.
• Correct hypocalcaemia and treat vitamin D deficiency or other mineral-metabolism disorders before initiation; this product is not suitable for correcting vitamin D deficiency.
• Assess renal function, oesophageal disease, active upper gastrointestinal disease, malabsorption and causes of osteoporosis other than ageing or oestrogen deficiency.
• Review calcium intake, vitamin D sources, oral health and dental risk factors.
• Periodically reassess continued bisphosphonate therapy against individual benefits and risks.

Contraindications and cautions

• Hypersensitivity to either active substance or an excipient
• Oesophageal abnormalities or other factors delaying oesophageal emptying, including stricture or achalasia
• Inability to sit or stand upright for at least 30 minutes
• Hypocalcaemia

Monitoring

• Renal function before prescribing.
• Calcium and symptoms of hypocalcaemia in patients with mineral-metabolism disorders or other predisposing factors.
• Serum and urine calcium where calcitriol production may be unregulated, such as sarcoidosis, lymphoma or leukaemia.
• New dysphagia, odynophagia, retrosternal pain or worsening heartburn.
• Oral symptoms and dental health; investigate persistent ear pain or discharge where clinically relevant.
• New thigh, hip or groin pain for possible incomplete atypical fracture.

Clinical pharmacology

Alendronate localises to active bone-resorption surfaces and inhibits osteoclast activity. Its oral bioavailability is very low and falls further with food or many drinks and medicines; absorbed alendronate is incorporated into bone and released slowly. Colecalciferol is converted in the liver to its storage metabolite and in the kidney to calcitriol, which regulates calcium and phosphate handling.

Formulation and product differences

• The selected product is available as two tablet presentations with the same alendronate content but different colecalciferol content.
• The lower-colecalciferol presentation is capsule-shaped and marked with a bone outline and “710”; the higher presentation is rectangular and marked with a bone outline and “270”.
• Both presentations contain lactose and sucrose and should remain in the original blister to protect them from moisture and light.