Alendronic acid + Colecalciferol

Oral
Increase bone mass in men with osteoporosis, Postmenopausal osteoporosis

Mild to moderate: No dosage adjustment needed.

No dosage adjustment needed.

Hypersensitivity to other bisphosphonates and vit D derivatives. Hypocalcaemia; abnormalities of oesophagus (e.g. archalasia or stricture); inability to stand or sit upright for at least 30 min.

Patient w/ underlying upper GI disease. Correct vit D deficiency and hypocalcaemia prior to therapy. May exacerbate hypercalciuria and hypercalcaemia in patients w/ diseases associated w/ unregulated production of calcitriol (e.g. leukaemia, lymphoma, sarcoidosis). Hepatic and severe renal impairment. Pregnancy and lactation.

Abdominal pain, dyspepsia, oesophageal ulcer, dysphagia, abdominal distension and acid regurgitation; diaphyseal and subtrochanteric femur fracture; severe muscle, bone and joint pain; upper GI mucosa irritation; osteonecrosis of the jaw; oesophageal cancer; headache, dizziness, vertigo, alopecia, pruritus, asthenia, peripheral oedema.

PO: C

Alendronate: Symptoms: Heartburn, gastritis, ulcer, upset stomach and oesophagitis, hypocalcaemia, hypophosphataemia. Management: Administer antacids or milk.

NSAIDs may increase risk GI ulceration and nephrotoxicity of alendronate. Antacids and Ca salts may decrease serum concentration of alendronate. Mineral oil, orlistat, cholestyramine and colestipol may impair vit D absorption. Anticonvulsants, cimetidine and thiazide diuretics may increase vit D catabolism.

Food, mineral water, coffee, tea and juice interfere w/ absorption of alendronate.

Description:
Mechanism of Action: Alendronate Na is a synthetic bisphosphonate which inhibits osteoclast-mediated bone resorption that leads to an indirect elevation in bone mineral density. Colecalciferol is produced in the skin by converting 7-dehydrocholesterol to split (seco) sterol previt D3 and subsequently colecalciferol (vit D3) via UV light which is an essential dietary nutrient when adequate sunlight exposure is not present. Vitamin D3 is the natural precursor of Ca-mobilising hormone 1,25-dihydroxyvitamin D3 (calcitriol). Calcitriol increases intestinal absorption of both Ca and phosphate as well as regulate serum Ca, renal Ca and phosphate excretion, bone formation and bone resorption.
Pharmacokinetics:
Absorption: Alendronate: Poorly absorbed and absorption is reduced by food. Bioavailability: Approx 0.4%.
Distribution: Alendronate: Volume of distribution: 28 L (exclusively on bones). Plasma protein binding: Approx 78%. Colecalciferol: Distributed primarily in the liver. Plasma protein binding: Binds extensively to vit D-binding protein.
Metabolism: Colecalciferol: Primarily hepatic and renal hydroxylation; minimal glucuronidation.
Excretion: Alendronate: Via urine; faeces (as unchanged drug). Elimination half-life: >10 yr. Colecalciferol: Via urine (2.4%) and faeces (4.9%) both as metabolites. Half-life: 14 hr.

Store between 20-25°C.

Agents Affecting Bone Metabolism

A11CC55 - colecalciferol, combinations ; Belongs to the class of vitamin D and analogues. Used as dietary supplements.

Anon. Alendronate and Cholecalciferol. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 05/09/2013.

Anon. Alendronate Sodium. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 05/09/2013.

Anon. Ergocalciferol. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 06/09/2013.

Buckingham R (ed). Alendronate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 05/09/2013.

Fosamax Plus D (Merck Sharp & Dohme Limited). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 05/09/2013.