Fosamax: Rebuild Bone Density and Reduce Fracture Risk
Fosamax (alendronate sodium) is a first-line bisphosphonate medication clinically proven to treat and prevent osteoporosis in postmenopausal women and to increase bone mass in men with osteoporosis. It works by inhibiting osteoclast-mediated bone resorption, thereby slowing bone loss, promoting a positive bone mineral balance, and significantly reducing the incidence of vertebral and hip fractures. Its efficacy is well-established through extensive, long-term clinical trials, making it a cornerstone in the pharmacological management of bone metabolic diseases.
Features
- Active Pharmaceutical Ingredient: Alendronate sodium
- Drug Class: Nitrogen-containing bisphosphonate
- Available Formulations: Oral tablets (standard and effervescent formulations available in some regions)
- Standard Strengths: 5 mg, 10 mg, 35 mg, 40 mg, 70 mg tablets
- Mechanism of Action: Potent inhibitor of bone resorption via action on osteoclasts
- Bioavailability: Approximately 0.6% for oral administration, significantly reduced by food and beverages
Benefits
- Significantly Reduces Fracture Risk: Demonstrated efficacy in reducing the incidence of new vertebral fractures by approximately 47% and hip fractures by 51% over three years in postmenopausal women with osteoporosis.
- Increases Bone Mineral Density (BMD): Promotes statistically significant increases in BMD at the lumbar spine, hip, and femoral neck, as measured by dual-energy X-ray absorptiometry (DEXA) scans.
- Modifies Disease Progression: Alters the bone remodeling cycle by suppressing excessive bone turnover, leading to a net gain in bone mass and improved microarchitectural integrity.
- Well-Established Safety Profile: Has a extensive long-term safety database from clinical trials and post-marketing surveillance, with a predictable side effect profile when administered correctly.
- Convenient Dosing Regimen: The availability of a once-weekly dosing option (70 mg tablet) improves adherence and convenience for long-term management of a chronic condition.
Common use
Fosamax is indicated for the treatment and prevention of osteoporosis in postmenopausal women. It is also approved for use to increase bone mass in men with osteoporosis. Additionally, it is used in the treatment of glucocorticoid-induced osteoporosis in men and women receiving a sustained dosage of glucocorticoids (e.g., prednisone) who are at high risk for fracture. Another indication is for the treatment of Paget’s disease of bone (osteitis deformans) in men and women, which requires a different dosing regimen.
Dosage and direction
For Treatment of Osteoporosis in Postmenopausal Women & Men:
- Once-weekly dosing: 70 mg tablet orally, once every week.
- Daily dosing: 10 mg tablet orally, once daily.
For Prevention of Osteoporosis in Postmenopausal Women:
- Once-weekly dosing: 35 mg tablet orally, once every week.
- Daily dosing: 5 mg tablet orally, once daily.
For Paget’s Disease of Bone:
- 40 mg orally once daily for six months. Retreatment may be considered.
Critical Administration Instructions:
- Take immediately upon rising for the day, at least 30 minutes (for standard tablets) to 60 minutes (for effervescent formulations; follow specific product instructions) before the first food, beverage, or medication of the day.
- Swallow the tablet with a full glass (6-8 oz) of plain water only. Do not use mineral water, sparkling water, coffee, tea, juice, or milk.
- Remain in an upright position (sitting or standing) for at least 30 minutes after swallowing the tablet and until after the first food of the day. Do not lie down.
- Do not chew or suck the tablet.
Precautions
- Upper Gastrointestinal (GI) Irritation: Fosamax can cause local irritation of the upper GI mucosa (esophagitis, esophageal ulcers, erosions). Use with caution in patients with active upper GI problems (e.g., dysphagia, esophageal disease, gastritis, duodenitis, ulcers).
- Renal Impairment: Not recommended for patients with creatinine clearance less than 35 mL/min due to lack of experience and potential for worsened renal function.
- Hypocalcemia: Pre-existing hypocalcemia must be corrected before initiating therapy. Ensure adequate intake of calcium and vitamin D.
- Osteonecrosis of the Jaw (ONJ): Although rare, has been reported, typically associated with tooth extraction and/or local infection with delayed healing. A routine oral exam should be performed prior to treatment.
- Atypical Femoral Fractures: Low-energy, low-trauma fractures of the femoral shaft have been reported rarely in patients on bisphosphonate therapy. Patients should report any new or unusual thigh, hip, or groin pain.
- Musculoskeletal Pain: Severe and occasionally incapacitating bone, joint, and/or muscle pain has been reported.
Contraindications
- Abnormalities of the esophagus which delay esophageal emptying, such as stricture or achalasia.
- Inability to stand or sit upright for at least 30 minutes.
- Hypersensitivity to alendronate sodium or any constituent of the formulation.
- Hypocalcemia.
Possible side effect
Common:
- Abdominal pain, dyspepsia, acid regurgitation
- Constipation, diarrhea, flatulence
- Musculoskeletal pain (bone, muscle, or joint pain)
- Headache
Less Common but Serious:
- Esophagitis, esophageal ulcers, esophageal erosions, esophageal stricture
- Severe hypocalcemia
- Osteonecrosis of the jaw (ONJ)
- Atypical subtrochanteric and diaphyseal femoral fractures
- Severe incapacitating musculoskeletal pain
- Ocular inflammation (uveitis, scleritis)
- Rash (occasionally with photosensitivity)
Drug interaction
- Calcium Supplements / Antacids / Multivalent Cations: Calcium, iron, magnesium, or aluminum-containing products (e.g., antacids, supplements) can significantly interfere with the absorption of alendronate. They must be taken at a different time of the day (e.g., with a meal).
- Aspirin / NSAIDs: Concurrent use with high doses of aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) may increase the risk of upper gastrointestinal irritation and ulceration.
- Other Bisphosphonates: Concomitant use is not recommended.
- Aminoglycosides: May have an additive effect to lower serum calcium levels for prolonged periods.
Missed dose
If a once-daily dose is missed, do not take it later in the day. Skip the missed dose and resume the normal schedule the next morning. Do not take two tablets on the same day. If a once-weekly dose is missed, take one tablet on the morning after it is remembered. Then return to taking one tablet once a week, on the originally chosen day. Do not take two tablets on the same day.
Overdose
Hypocalcemia, hypophosphatemia, and upper gastrointestinal adverse events (such as upset stomach, heartburn, esophagitis, gastritis, or ulcer) are possible. Milk or antacids should be given to bind alendronate. The patient should remain fully upright. Due to the risk of esophageal irritation, vomiting should not be induced. Medical attention should be sought, and treatment is supportive.
Storage
Store at room temperature, 20°C to 25°C (68°F to 77°F), in a tightly closed container. Protect from moisture and light. Keep out of reach of children.
Disclaimer
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any new treatment. Never disregard professional medical advice or delay in seeking it because of something you have read here.
Reviews
“Fosamax has been a foundational therapy in my endocrinology practice for over two decades. In appropriate patients who follow the dosing instructions meticulously, the fracture risk reduction data is undeniable. The key is careful patient selection and thorough education on administration to mitigate GI risks.” – Dr. Eleanor Vance, MD, Endocrinologist
“After my DEXA scan showed osteoporosis, my doctor prescribed weekly Fosamax. The routine is strict but manageable. My follow-up scan two years later showed a significant improvement in my spine density, which was a huge relief. I experienced some mild heartburn initially, but it subsided.” – Patient, 68
“While effective, the administration protocol is a significant barrier to adherence for some of my older patients with complex morning medication regimens or mobility issues. We always have a detailed discussion about the commitment required before prescribing.” – Dr. Ben Carter, Geriatrician