Alendronic Acid information from DrugsUpdate
L - Contraindicated in lactation
Alendronic acid or alendronate sodium is a bisphosphonate drug used for osteoporosis and several other bone diseases. It is marketed alone as well as in combination with vitamin D (2,800 U and 5600 U, under the name Fosamax+D).
Prophylaxis and treatment of female osteoporosis
Treatment of male osteoporosis
Prevention and treatment of corticosteroid-associated osteoporosis together with supplements of calcium and vitamin D
Alendronate inhibits osteoclast-mediated bone-resorption. Like all bisphosphonates it is chemically related to inorganic pyrophosphate, the endogenous regulator of bone turnover. Whereas pyrophosphate and the first bisphosphonate, etidronate, are capable of inhibiting both osteoclastic bone resorption as well as the mineralization of the bone newly formed by osteoblasts, alendronate and the other potent N-containing bisphosphonates such as risedronate and ibandronate and zoledronate specifically inhibit bone resorption without any effect on mineralization at pharmacalogically achievable doses. Its inhibition of bone-resorption is dose-dependent and approximately 1,000 times stronger than the equimolar effect of etidronate. Under therapy normal bone tissue develops, and alendronate is deposited in the bone-matrix in pharmacologically inactive form. For optimal action enough calcium and vitamin D are needed in the body in order to promote normal bone development. Hypocalcemia should therefore be corrected before starting therapy.
As with all potent bisphosphonates, the systemic bioavailability after oral dosing is low, averaging only 0.6–0.7% in women and in men under fasting conditions. Intake together with meals and beverages other than water further reduces the bioavailability. The absorbed drug rapidly partitions, with approximately 50% binding to the exposed bone surface; the remainder is excreted unchanged by the kidneys. Unlike most drugs, the strong negative charge on the two phosphate moieties limits oral bioavailability, and in turn, the exposure to tissues other than bone is very low. After absorption in the bone, alendronate has an estimated terminal half-life of 10 years.
Oesophagitis, oesophageal ulcers, & erosions, dysphagia, heartburn, retrosternal pain, abdominal pain, distension, diarrhoea, constipation, flatulance, headcahe, rash, erthyema, musculoskeletal pain, transient decreases in serum phospate.
Acute inflammations of the gastrointestinal tract (esophagitis, gastritis, ulcerations). Clinically manifest osteomalacia. Certain malformations and malfunctions of the esophagus (strictures, achalasia). Inability to stand, walk, or sit for 30 minutes after oral administration, Renal impairment with a creatinine clearance below 30ml/min. Hypersensitivity to alendronate or another ingredient. Hypocalcemia Pregnancy and breastfeeding, Patients below 18 yrs. of age, because no clinical data exists.
Upper Gi disorders (discontinue if symptoms worsen); history of ulcers, active GI bleeding. Correct Vitamin D & Ca dificiency before starting therapy.
Highly active vitamin D analogues or fluorides: no data is available. Concomitant treatment should be avoided.
The additional beneficial effect of HRT (hormone replacement therapy) with estrogens/progestins or raloxifene in postmenopausal women remains to be elucidated, but no interactions have been seen. The combination is therefore possible.
Intravenous ranitidine increases the oral bioavailability of alendronate. No clinical consequences are known.
The combination of NSAIDs and alendroate may increase the risk of gastric ulcers. Both these drugs have the potential to irritate the upper gastro-intestinal mucosa.
Milk, diet and drugs containing high amounts of calcium, magnesium or aluminium (antacids): the resorption of alendronate is decreased.
Food, mineral water, coffee, tea and juice interfere with absorption of alendronate.
At least half an hour should pass after intake of alendronate before taking the supplement or drug.
Adult: 10 mg daily or 70 mg once weekly.
CrCl (ml/min) <35, Dosage not recommended.
Paget's disease of bone
Adult: 40 mg daily for 6 mth; may be repeated if necessary after 6-mth post-treatment evaluation period.
Prevention of postmenopausal osteoporosis
Adult: 5 mg once daily or 35 mg once wkly.
CrCl (ml/min) <35, Dosage not recommended.
Adult: Treatment and prevention: 5 mg daily; may increase to 10 mg daily in women who do not receive HRT.
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.)
List of Contraindications
Contraindicated in pregnancy.
Contraindicated in lactation