alendronate (Rx)

Brand and Other Names:Fosamax, Binosto, more...Fosamax Plus D
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Dosing & Uses


Dosage Forms & Strengths


  • 5mg
  • 10mg
  • 35mg
  • 40mg
  • 70mg

tablet for solution (effervescent)

  • 70mg

solution, oral

  • 70mg/75mL


Prevention in postmenopausal women

  • 5 mg PO once daily or 35 mg PO once weekly

Treatment in postmenopausal women and men

  • 10 mg PO once daily or 70 mg PO once weekly

Glucocorticoid-Induced Osteoporosis

Males and females: 5 mg PO once daily (10 mg/day for postmenopausal women not on hormone replacement therapy)

Paget Disease

40 mg/day PO for 6 months

Dosing Modifications

Mild-to-moderate renal impairment (CrCl 35-60 mL/min): Dose adjustment not necessary

Severe renal impairment (CrCl <35 mL/min): Not recommended


Take only in morning, not at bedtime or before arising

Take tablet with full glass of water (6-8 oz) at least 30 minutes before first food or drink of day, in upright position

Administer oral solution with at least 2 ounces of water

Swallow with plain water only; mineral water, coffee, juice or other beverages severely reduces bioavailability

Swallow tablet whole; do not suck or chew

Do not lie down for 30 minutes after taking drug; sit or stand upright

Despite long terminal half-life (10 years), bone-incorporated drug is not pharmacologically active

If dietary intake is inadequate, patients should receive calcium supplement and vitamin D

Limitation of Use

Optimal duration of use not determined; for patients at low-risk for fracture, consider drug discontinuation after 3-5 years of use

Safety and efficacy not established

Osteogenesis Imperfecta (Orphan)

Treatment in pediatric patients aged 4 years or older

Orphan indication sponsor

  • Merck, Sharpe & Dohme Corp; 126 East Lincoln Ave, PO Box 2000; Rahway, NJ 07065-0900

Gaucher Disease (Orphan)

Treatment of bone manifestations of disease

Orphan indication sponsor

  • Richard J Wenstrup, MD; Division of Human Genetics, Children's Hospital Research Foundation; Cincinnati, OH 45229-3039


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            Adverse Effects


            Hypocalcemia, transient and mild (18%)


            Hypophosphatemia, transient and mild (10%)

            Abdominal pain (7%)

            Musculoskeletal pain (4.1%)

            Dyspepsia (3.6%)

            Nausea (3.6%)

            Constipation (3.1%)

            Diarrhea (3.1%)

            Flatulence (2.6%)

            Headache (2.6%)

            Acid regurgitation (2%)

            Esophagitis (1.5%)

            Abdominal distention (1%)



            Diaphyseal femur fracture

            Esophageal cancer

            Flulike syndrome



            Oropharyngeal ulceration



            Taste perversion

            Toxic epidermal necrolysis




            Postmarketing Reports

            Body as a whole: Hypersensitivity reactions including urticaria and angioedema; transient myalgia, malaise, asthenia, and fever; symptomatic hypocalcemia; peripheral edema

            Gastrointestinal: Esophagitis, esophageal erosions, esophageal ulcers, esophageal stricture or perforation, and oropharyngeal ulceration; gastric or duodenal ulcers

            Localized osteonecrosis of the jaw, generally associated with tooth extraction and/or local infection with delayed healing

            Musculoskeletal: Bone, joint, and/or muscle pain, occasionally severe, and incapacitating; joint swelling; low-energy femoral shaft and subtrochanteric fractures

            Nervous system: dizziness, vertigo

            Pulmonary: Acute asthma exacerbations

            Skin: Rash (occasionally with photosensitivity), pruritus, alopecia, severe skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis

            Special Senses: Uveitis, scleritis, or episcleritis, cholesteatoma of the external auditory canal (focal osteonecrosis)






            Abnormalities of the esophagus delaying esophageal emptying such as stricture or achalasia

            Inability to stand or sit upright for 30 minutes


            May cause local irritation of upper GI mucosa

            Take with plain water only, not coffee, juice, or mineral water; sit or stand upright for at least 30 minutes after administration

            Hypocalcemia reported with use of bisphosphonates; correct hypocalcemia prior to therapy; ensure adequate calcium and vitamin D intake

            Conjunctivitis, uveitis, episcleritis, and scleritis reported with alendronate use; perform ophthalmic evaluation in patients with signs of ocular inflammation

            Avoid concomitant polyvalent cation-containing medications

            Osteonecrosis of the jaw, can occur spontaneously and is generally associated with tooth extraction and/or local infection with delayed healing; known risk factors include invasive dental procedures (e.g., tooth extraction, dental implants, boney surgery), diagnosis of cancer, concomitant therapies (e.g., chemotherapy, corticosteroids, angiogenesis inhibitors), poor oral hygiene, and co-morbid disorders; risk of osteonecrosis of the jaw may increase with duration of exposure to bisphosphonates

            Not recommended in severe renal impairment (CrCl <35 mL/min)

            In Paget disease, drug is available only through Paget's Patient Support Program with Pharma Care Specialty Pharmacy (800-238-7828 x58197) distribution system for 40-mg dosage regimen

            Risk of severe bone, joint, or muscle pain; discontinue therapy in patients who experience severe symptoms of pain; avoid use in patients with history of these symptoms in association with bisphosphonate therapy

            Possible increased risk of atypical subtrochanteric and diaphyseal femur fractures; may consider discontinuing therapy after 3-5 years in patients at low-risk for fracture; following discontinuation, re-evaluate fracture risk periodically; consider periodic reevaluation of need for continued bisphosphonate therapy, particularly if treatment lasts >5 years; patients with new thigh or groin pain should be evaluated to rule out a femoral fracture

            Use effervescent tablet with caution in sodium-restricted patients (tablet contains 650 mg of sodium)


            Pregnancy & Lactation


            Available data on use in pregnant women insufficient to inform a drug-associated risk of adverse maternal or fetal outcomes; discontinue when pregnancy recognized.

            Animal data

            • In animal reproduction studies, daily oral administration to rats from before mating through end of gestation or lactation showed decreased postimplantation survival and decreased pup body weight gain starting at doses equivalent to less than half of highest recommended 40 mg clinical daily dose (based on body surface area, mg/m2)
            • Oral administration to rats during organogenesis resulted in reduced fetal ossification starting at doses 3 times clinical daily dose of 40 mg;
            • No similar fetal effects observed in pregnant rabbits dosed orally during organogenesis at doses equivalent to approximately 10 times the 40 mg clinical daily dose
            • Delayed or failed delivery of offspring, protracted parturition, and late pregnancy maternal and fetal deaths due to maternal hypocalcemia occurred in rats at oral doses as low as one tenth the 40 mg clinical daily dose
            • Bisphosphonates are incorporated into the bone matrix, from which they are gradually released over a period of years; based on mechanism of action of bisphosphonates, there is a potential risk of fetal harm, predominantly skeletal, if a woman becomes pregnant after completing a course of bisphosphonate therapy
            • Impact of variables such as time between cessation of bisphosphonate therapy to conception, particular bisphosphonate used, and route of administration (intravenous versus oral) on risk not studied


            Not known whether drug present in human breast mild, affects milk production or has effects on infants

            Consider developmental and health benefits of breastfeeding along with mother’s clinical need for therapy and any potential effects on breastfed child from drug or underlying maternal condition

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.



            Mechanism of Action

            Bisphosphonate; binds to hydroxyapatite crystals in bone and inhibits osteoclast-mediated bone resorption; decreases mineral release and collagen or matrix breakdown in bone


            Bioavailability (fasting): Women, 0.64%; men, 0.59%; reduced up to 60% by food

            Onset: 3 weeks

            Duration: 12-30 weeks (multiple doses)


            Protein bound: 78%

            Vd: 28 L (exclusive of bone)


            Not metabolized


            Half-life: Up to 10 years in bone (terminal)

            Excretion: Urine 50%, feces (unabsorbed drug)





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            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.