Alendronic Acid

Indications

Oral
Osteopetrosis
Adult: 10 mg daily or 70 mg once wkly.

CrCl (ml/min)	Dosage Recommendation
<35	Not recommended.

Oral
Paget's disease of bone
Adult: 40 mg daily for 6 mth; may be repeated if necessary after 6-mth post-treatment evaluation period.
Oral
Prophylaxis of postmenopausal osteoporosis
Adult: 5 mg once daily or 35 mg once wkly.

CrCl (ml/min)	Dosage Recommendation
<35	Not recommended.

Oral
Corticosteroid-induced osteoporosis
Adult: Treatment and prevention: 5 mg daily; may increase to 10 mg daily in women who do not receive HRT.

Special Populations: Do not take this medication with mineral water, coffee, tea or juice, and at bedtime or before rising. Stand or sit upright for at least 30 min and do not lie down until after breakfast.

Contraindications

Hypocalcaemia; oesophageal abnormalities and factors which delay oesophageal emptying; severe renal impairment; hypersensitivity; inability to stand or sit upright for ≥30 min. Pregnancy, lactation.

Warnings / Precautions

Upper GI disorders (discontinue if symptoms worsen); history of ulcers, active GI bleeding. Correct vitamin D and calcium deficiency before starting therapy. To be taken half an hr before breakfast and remain upright for at least 30 minutes after admin. Not recommended for use in patients with CrCl <35 ml/min.

Adverse Reactions

Oesophagitis, oesophageal ulcers and erosions, dysphagia, heartburn, retrosternal pain, abdominal pain, distension, diarrhoea, constipation, flatulence, headache, rash, erythema, musculoskeletal pain, transient decreases in serum phosphate.

Overdose Reactions

Symptoms may include hypocalcaemia, hypophosphataemia and upper GI adverse events, such as upset stomach, heartburn, esophagitis, gastritis or ulcer. Milk or antacids should be given to bind alendronate. Should not induce vomiting due to the risk of oesophageal irritation. Patient should remain fully upright. Dialysis would not be beneficial.

Drug Interactions

Concomitant iron, calcium supplements and antacids hinder alendronate absorption. Concomitant aspirin or NSAIDs may increase the incidence of adverse GI effects.
See Below for More alendronic acid Drug Interactions

Food Interactions

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

Mechanism of Actions

Alendronic acid reduces bone resorption by inhibiting the action of osteoclasts.
Absorption: Poorly absorbed from the GIT (oral); reduced by food.
Distribution: Protein-binding: 78%
Excretion: Urine (50%); remainder is sequestered to bone.

Administration

Should be taken on an empty stomach. (Take w/ a full glass of plain water at least ½ hr before the 1st food/drink/medication of the day & remain in sitting/upright position for at least ½ hr. Swallow whole, do not chew/crush.)