Short answer: Alendronate has a half-life of more than 10 years (in bone). People vary, so treat these as estimates.
Alendronate is a bisphosphonate, a drug that binds to bone and slows the cells that break bone down, so bone density rises. It is sold as Fosamax (Organon) and as generic tablets, for osteoporosis and Paget's disease of bone.
Also known as: Fosamax, alendronate sodium.
Fosamax is now marketed as a 70 mg tablet taken once a week; the label still lists the 5, 10, 35 and 40 mg daily and weekly doses and the trials behind them. Alendronate is also sold as generic tablets.
The Fosamax label approves alendronate to treat and prevent osteoporosis in women after menopause, to build bone in men with osteoporosis, to treat steroid-caused osteoporosis, and to treat Paget's disease of bone. For osteoporosis the label dose is 70 mg once a week or 10 mg once a day. The tablet is swallowed on getting up with 6 to 8 ounces of plain water, at least 30 minutes before the first food, drink or other medicine of the day, and without lying down for 30 minutes after. Taking it with or after breakfast, coffee or orange juice cut absorption sharply. The label says the best length of use is not known, and people at low fracture risk may be considered for stopping after 3 to 5 years.
The label has no boxed warning. Its warnings cover irritation and ulcers of the esophagus, low calcium (which is corrected before starting), bone, joint and muscle pain, jaw bone death (osteonecrosis of the jaw) and unusual thigh fractures. It is not used with problems of the esophagus that slow emptying, in people who cannot stand or sit upright for 30 minutes, or with low calcium. In the 3-year trials, the most common drug-related side effects were stomach-related, such as belly pain (6.6% on 10 mg vs 4.8% on placebo). Full numbers are on the Fosamax side effects, Fosamax dosing schedule and missed Fosamax dose pages.
The Fosamax label says only about 0.64% of a dose is absorbed when taken after an overnight fast, 2 hours before breakfast, and absorption fell about 40% when taken 30 to 60 minutes before breakfast. Blood levels fall more than 95% within 6 hours after an IV dose as the drug goes into bone or leaves in urine, but the terminal half-life is estimated at more than 10 years, because alendronate is slowly released from the skeleton. The label gives no time to peak.
Numbers shown are taken from the source above. Half-life varies from person to person.
How Dose Track handles peptides · Reconstitution calculator · Half-life calculator