Molecule

Drug Groups

approved

Description

Alendronate is a nitrogen-containing, second generation bisphosphonate. Bisphosphonates were first used to treat Paget’s disease in 1971. This class of medications is comprised of inorganic pyrophosphate analogues that contain non-hydrolyzable P-C-P bonds. Similar to other bisphosphonates, alendronate has a high affinity for bone mineral and is taken up during osteoclast resorption. Alendronate inhibits farnesyl pyrophosphate synthetase, one of the enzymes in the mevalonic acid pathway involved in producing isoprenoid compounds that are essential for post-translational modification of small guanosine triphosphate (GTP)-binding proteins, such as Rho, Ras and Rab. Inhibition of this process interferes with osteoclast function and survival. Alendronate is used for the treatment of osteoporosis and Paget’s disease.

Indication

For the treatment and prevention of osteoporosis in women and Paget's disease of bone in both men and women.

Pharmacology

Alendronate, a second-generation bisphosphonate is the first member of a group of drugs which strengthens bone. Alendronate is used to reduce hypercalcemia in tumor-induced bone disease, to treat corticosteroid-induced osteoporosis and Paget's disease, and to prevent osteoporosis in postmenopausal women.

Toxicity

Alendronate can damage the esophagus both by toxicity from the medication itself and by nonspecific irritation secondary to contact between the pill and the esophageal mucosa, similar to other cases of "pill esophagitis."

Affected Organisms

Biotransformation

There is no evidence that alendronate is metabolized in humans or animals.

Absorption

Relative to an intravenous (IV) reference dose, the mean oral bioavailability of alendronate in women was 0.7% for doses ranging from 5 to 40 mg when administered after an overnight fast and two hours before a standardized breakfast. Oral bioavailability of the 10 mg tablet in men (0.59%) was similar to that in women (0.78%) when administered after an overnight fast and 2 hours before breakfast.

Half Life

>10 years

Protein Binding

78%

Elimination

Following a single IV dose of [14C]alendronate, approximately 50% of the radioactivity was excreted in the urine within 72 hours and little or no radioactivity was recovered in the feces.

Distribution

* 28 L

Clearance

* <200 mL/min [A single 10?mg IV dose]

References

External Links