FOSAMAX® PLUS D is indicated for:
Treatment of Osteoporosis in Postmenopausal Women
For the treatment of osteoporosis, Fosamax Plus D increases bone mass and reduces the incidence of fractures, including those of the hip and spine (vertebral compression fractures).
Treatment to Increase Bone Mass in Men with Osteoporosis
Important Limitations of Use
Fosamax Plus D alone should not be used to treat vitamin D deficiency.
The safety and effectiveness of Fosamax Plus D for the treatment of osteoporosis are based on clinical data of four years duration. The optimal duration of use has not been determined. All patients on bisphosphonate therapy should have the need for continued therapy re-evaluated on a periodic basis.
Fosamax Plus D Dosage and Administration
Treatment of Osteoporosis in Postmenopausal Women
The recommended dosage is one 70 mg alendronate/2800 IU vitamin D3 or one 70 mg alendronate/5600 IU vitamin D3 tablet once weekly. For most osteoporotic women, the appropriate dose is Fosamax Plus D (70 mg alendronate/5600 IU vitamin D3) once weekly.
Treatment to Increase Bone Mass in Men with Osteoporosis
The recommended dosage is one 70 mg alendronate/2800 IU vitamin D3 or one 70 mg alendronate/5600 IU vitamin D3 tablet once weekly. For most osteoporotic men, the appropriate dose is Fosamax Plus D (70 mg alendronate/5600 IU vitamin D3) once weekly.
Dosing Instructions
Fosamax Plus D must be taken at least one-half hour before the first food, beverage, or medication of the day with plain water only [see Medication Guide]. Other beverages (including mineral water), food, and some medications are likely to reduce the absorption of alendronate [see Drug Interactions (7.1)]. Waiting less than 30 minutes, or taking Fosamax Plus D with food, beverages (other than plain water) or other medications will lessen the effect of alendronate by decreasing its absorption into the body.
To facilitate delivery to the stomach and thus reduce the potential for esophageal irritation, Fosamax Plus D should only be swallowed upon arising for the day with a full glass of water (6-8 oz) and patients should not lie down for at least 30 minutes and until after their first food of the day. Fosamax Plus D should not be taken at bedtime or before arising for the day. Failure to follow these instructions may increase the risk of esophageal adverse experiences [see Warnings and Precautions (5.1); Medication Guide].
Recommendations for Calcium and Vitamin D Supplementation
Patients should receive supplemental calcium if dietary intake is inadequate [see Warnings and Precautions (5.2)]. Patients at increased risk for vitamin D insufficiency (e.g., over the age of 70 years, nursing home bound, or chronically ill) may need additional vitamin D supplementation. Patients with gastrointestinal malabsorption syndromes may require higher doses of vitamin D supplementation and measurement of 25-hydroxyvitamin D should be considered.
The recommended intake of vitamin D is 400 IU-800 IU daily. Fosamax Plus D 70 mg/2800 IU and 70 mg/5600 IU are intended to provide seven days’ worth of 400 and 800 IU daily vitamin D in a single, once-weekly dose, respectively.
Causes of osteoporosis other than estrogen deficiency, aging, and glucocorticoid use should be considered.
Dosing in Elderly and Renal Insufficiency
No dosage adjustment is necessary for the elderly or for patients with mild-to-moderate renal insufficiency (creatinine clearance 35 to 60 mL/min). Fosamax Plus D is not recommended for patients with more severe renal insufficiency (creatinine clearance <35 mL/min) due to lack of experience.
Dosage Forms and Strengths
- 70 mg/2800 IU tablets are white to off-white, modified capsule-shaped tablets with code 710 on one side and an outline of a bone image on the other.
- 70 mg/5600 IU tablets are white to off-white, modified rectangle-shaped tablets with code 270 on one side and an outline of a bone image on the other.
Contraindications
- Abnormalities of the esophagus which delay esophageal emptying such as stricture or achalasia [see Warnings and Precautions (5.1)]
- Inability to stand or sit upright for at least 30 minutes [see Dosage and Administration (2.3), Warnings and Precautions (5.1)]
- Hypocalcemia [see Warnings and Precautions (5.2)]
- Hypersensitivity to any component of this product. Hypersensitivity reactions including urticaria and angioedema have been reported [see Adverse Reactions (6.2)].
Warnings and Precautions
Upper Gastrointestinal Adverse Reactions
Fosamax Plus D, like other bisphosphonates administered orally, may cause local irritation of the upper gastrointestinal mucosa. Because of these possible irritant effects and a potential for worsening of the underlying disease, caution should be used when Fosamax Plus D is given to patients with active upper gastrointestinal problems (such as known Barrett's esophagus, dysphagia, other esophageal diseases, gastritis, duodenitis, or ulcers).
Esophageal adverse experiences, such as esophagitis, esophageal ulcers and esophageal erosions, occasionally with bleeding and rarely followed by esophageal stricture or perforation, have been reported in patients receiving treatment with oral bisphosphonates including Fosamax Plus D. In some cases these have been severe and required hospitalization. Physicians should therefore be alert to any signs or symptoms signaling a possible esophageal reaction and patients should be instructed to discontinue Fosamax Plus D and seek medical attention if they develop dysphagia, odynophagia, retrosternal pain or new or worsening heartburn.
The risk of severe esophageal adverse experiences appears to be greater in patients who lie down after taking oral bisphosphonates including Fosamax Plus D and/or who fail to swallow oral bisphosphonates including Fosamax Plus D with the recommended full glass (6-8 oz) of water, and/or who continue to take oral bisphosphonates including Fosamax Plus D after developing symptoms suggestive of esophageal irritation. Therefore, it is very important that the full dosing instructions are provided to, and understood by, the patient [see Dosage and Administration (2.3)]. In patients who cannot comply with dosing instructions due to mental disability, therapy with Fosamax Plus D should be used under appropriate supervision.
There have been post-marketing reports of gastric and duodenal ulcers with oral bisphosphonate use, some severe and with complications, although no increased risk was observed in controlled clinical trials [see Adverse Reactions (6.2)].
Mineral Metabolism
Alendronate Sodium
Hypocalcemia must be corrected before initiating therapy with Fosamax Plus D [see Contraindications (4)]. Other disorders affecting mineral metabolism (such as vitamin D deficiency) should also be effectively treated. In patients with these conditions, serum calcium and symptoms of hypocalcemia should be monitored during therapy with Fosamax Plus D.
Presumably due to the effects of alendronate on increasing bone mineral, small, asymptomatic decreases in serum calcium and phosphate may occur.
Cholecalciferol
Fosamax Plus D alone should not be used to treat vitamin D deficiency (commonly defined as 25-hydroxyvitamin D level below 9 ng/mL). Patients at increased risk for vitamin D insufficiency may require higher doses of vitamin D supplementation [see Dosage and Administration (2.4)]. Patients with gastrointestinal malabsorption syndromes may require higher doses of vitamin D supplementation and measurement of 25-hydroxyvitamin D should be considered.
Vitamin D3 supplementation may worsen hypercalcemia and/or hypercalciuria when administered to patients with diseases associated with unregulated overproduction of 1,25 dihydroxyvitamin D (e.g., leukemia, lymphoma, sarcoidosis). Urine and serum calcium should be monitored in these patients.
Musculoskeletal Pain
In post-marketing experience, severe and occasionally incapacitating bone, joint, and/or muscle pain has been reported in patients taking bisphosphonates that are approved for the prevention and treatment of osteoporosis [see Adverse Reactions (6.2)]. This category of drugs includes alendronate. Most of the patients were postmenopausal women. The time to onset of symptoms varied from one day to several months after starting the drug. Discontinue use if severe symptoms develop. Most patients had relief of symptoms after stopping. A subset had recurrence of symptoms when rechallenged with the same drug or another bisphosphonate.
In placebo-controlled clinical studies of FOSAMAX, the percentages of patients with these symptoms were similar in the FOSAMAX and placebo groups.
Osteonecrosis of the Jaw
Osteonecrosis of the jaw (ONJ), which can occur spontaneously, is generally associated with tooth extraction and/or local infection with delayed healing, and has been reported in patients taking bisphosphonates, including Fosamax Plus D. Known risk factors for osteonecrosis of the jaw include invasive dental procedures (e.g., tooth extraction, dental implants, boney surgery), diagnosis of cancer, concomitant therapies (e.g., chemotherapy, corticosteroids), poor oral hygiene, and co-morbid disorders (e.g., periodontal and/or other pre-existing dental disease, anemia, coagulopathy, infection, ill-fitting dentures).
For patients requiring invasive dental procedures, discontinuation of bisphosphonate treatment may reduce the risk for ONJ. Clinical judgment of the treating physician and/or oral surgeon should guide the management plan of each patient based on individual benefit/risk assessment.
Patients who develop osteonecrosis of the jaw while on bisphosphonate therapy should receive care by an oral surgeon. In these patients, extensive dental surgery to treat ONJ may exacerbate the condition. Discontinuation of bisphosphonate therapy should be considered based on individual benefit/risk assessment.
Atypical Subtrochanteric and Diaphyseal Femoral Fractures
Atypical, low-energy, or low trauma fractures of the femoral shaft have been reported in bisphosphonate-treated patients. These fractures can occur anywhere in the femoral shaft from just below the lesser trochanter to above the supracondylar flare and are transverse or short oblique in orientation without evidence of comminution. Causality has not been established as these fractures also occur in osteoporotic patients who have not been treated with bisphosphonates.
Atypical femur fractures most commonly occur with minimal or no trauma to the affected area. They may be bilateral and many patients report prodromal pain in the affected area, usually presenting as dull, aching thigh pain, weeks to months before a complete fracture occurs. A number of reports note that patients were also receiving treatment with glucocorticoids (e.g. prednisone) at the time of fracture.
Any patient with a history of bisphosphonate exposure who presents with thigh or groin pain should be suspected of having an atypical fracture and should be evaluated to rule out an incomplete femur fracture. Patients presenting with an atypical fracture should also be assessed for symptoms and signs of fracture in the contralateral limb. Interruption of bisphosphonate therapy should be considered, pending a risk/benefit assessment, on an individual basis.
Renal Insufficiency
Fosamax Plus D is not recommended for patients with renal insufficiency (creatinine clearance <35 mL/min). [See Dosage and Administration (2.5).]
Adverse Reactions
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
FOSAMAX
FOSAMAX has been evaluated for safety in approximately 8000 postmenopausal women in clinical studies.
Postmenopausal Women
FOSAMAX daily
In two identically designed, three-year, placebo-controlled, double-blind, multicenter studies (United States and Multinational; n=994), discontinuation of therapy due to any clinical adverse experience occurred in 4.1% of 196 patients treated with FOSAMAX 10 mg/day and 6.0% of 397 patients treated with placebo. In the Fracture Intervention Trial (n=6459), discontinuation of therapy due to any clinical adverse experience occurred in 9.1% of 3236 patients treated with FOSAMAX 5 mg/day for 2 years and 10 mg/day for either one or two additional years and 10.1% of 3223 patients treated with placebo. Discontinuations due to upper gastrointestinal adverse experiences were: FOSAMAX, 3.2%; placebo, 2.7%. In these study populations, 49-54% had a history of gastrointestinal disorders at baseline and 54-89% used nonsteroidal anti-inflammatory drugs or aspirin at some time during the studies. Adverse experiences from these studies considered by the investigators as possibly, probably, or definitely drug related in ≥1% of patients treated with either FOSAMAX or placebo are presented in Table 1.
| United States/Multinational Studies | Fracture Intervention Trial | |||
| FOSAMAX* % (n=196) | Placebo % (n=397) | FOSAMAX† % (n=3236) | Placebo % (n=3223) | |
| ||||
| Gastrointestinal abdominal pain nausea dyspepsia constipation diarrhea flatulence acid regurgitation esophageal ulcer vomiting dysphagia abdominal distention gastritis | 6.6 3.6 3.6 3.1 3.1 2.6 2.0 1.5 1.0 1.0 1.0 0.5 | 4.8 4.0 3.5 1.8 1.8 0.5 4.3 0.0 1.5 0.0 0.8 1.3 | 1.5 1.1 1.1 0.0 0.6 0.2 1.1 0.1 0.2 0.1 0.0 0.6 | 1.5 1.5 1.2 0.2 0.3 0.3 0.9 0.1 0.3 0.1 0.0 0.7 |
| Musculoskeletal musculoskeletal (bone, muscle or joint) pain muscle cramp | 4.1 0.0 | 2.5 1.0 | 0.4 0.2 | 0.3 0.1 |
| Nervous System/Psychiatric headache dizziness | 2.6 0.0 | 1.5 1.0 | 0.2 0.0 | 0.2 0.1 |
| Special Senses taste perversion | 0.5 | 1.0 | 0.1 | 0.0 |
Rarely, rash and erythema have occurred.
The adverse experience profile was similar for the 401 patients treated with either 5- or 20-mg doses of FOSAMAX in the United States and Multinational studies. The adverse experience profile for the 296 patients who received continued treatment with either 5- or 10-mg doses of FOSAMAX in the two-year extension of these studies (treatment years 4 and 5) was similar to that observed during the three-year placebo-controlled period. During the extension period, of the 151 patients treated with FOSAMAX 10 mg/day, the proportion of patients who discontinued therapy due to any clinical adverse experience was similar to that during the first three years of the study.
FOSAMAX Once-Weekly
In a one-year, double-blind, multicenter study, the overall safety and tolerability profiles of once weekly FOSAMAX 70 mg and FOSAMAX 10 mg daily were similar. The adverse experiences considered by the investigators as possibly, probably, or definitely drug related in ≥1% of patients in either treatment group are presented in Table 2.
| Once Weekly FOSAMAX 70 mg % (n=519) | FOSAMAX 10 mg/day % (n=370) | |
| Gastrointestinal abdominal pain dyspepsia acid regurgitation nausea abdominal distention constipation flatulence gastritis gastric ulcer | 3.7 2.7 1.9 1.9 1.0 0.8 0.4 0.2 0.0 | 3.0 2.2 2.4 2.4 1.4 1.6 1.6 1.1 1.1 |
| Musculoskeletal musculoskeletal (bone, muscle, joint) pain muscle cramp | 2.9 0.2 | 3.2 1.1 |
Concomitant Use With Estrogen or Estrogen/Progestin Products
In two studies (of one and two years’ duration) of postmenopausal osteoporotic women (total: n=853), the safety and tolerability profile of combined treatment with FOSAMAX 10 mg once daily and estrogen ± progestin (n=354) was consistent with those of the individual treatments.
Men
In two placebo-controlled, double-blind, multicenter studies in men (a two-year study of FOSAMAX 10 mg/day and a one-year study of once weekly FOSAMAX 70 mg) the rates of discontinuation of therapy due to any clinical adverse experience were 2.7% for FOSAMAX 10 mg/day vs. 10.5% for placebo, and 6.4% for once weekly FOSAMAX 70 mg vs. 8.6% for placebo. The adverse experiences considered by the investigators as possibly, probably, or definitely drug related in ≥2% of patients treated with either FOSAMAX or placebo are presented in Table 3.
| Two-year Study | One-year Study | |||
FOSAMAX 10 mg/day % (n=146) | Placebo % (n=95) | Once Weekly FOSAMAX 70 mg % (n=109) | Placebo % (n=58) | |
| Gastrointestinal acid regurgitation flatulence gastroesophageal reflux disease dyspepsia diarrhea abdominal pain nausea | 4.1 4.1 0.7 3.4 1.4 2.1 2.1 | 3.2 1.1 3.2 0.0 1.1 1.1 0.0 | 0.0 0.0 2.8 2.8 2.8 0.9 0.0 | 0.0 0.0 0.0 1.7 0.0 3.4 0.0 |
Laboratory Test Findings
In double-blind, multicenter, controlled studies, asymptomatic, mild, and transient decreases in serum calcium and phosphate were observed in approximately 18% and 10%, respectively, of patients taking FOSAMAX versus approximately 12% and 3% of those taking placebo. However, the incidences of decreases in serum calcium to <8.0 mg/dL (2.0 mM) and serum phosphate to ≤2.0 mg/dL (0.65 mM) were similar in both treatment groups.
Fosamax Plus D
In a fifteen-week double-blind, multinational study in osteoporotic postmenopausal women (n=682) and men (n=35), the safety profile of Fosamax Plus D (70 mg/2800 IU) was similar to that of FOSAMAX once weekly 70 mg. In the 24-week double-blind extension study in women (n=619) and men (n=33), the safety profile of Fosamax Plus D (70 mg/2800 IU) administered with an additional 2800 IU vitamin D3 was similar to that of Fosamax Plus D (70 mg/2800 IU).
Post-Marketing Experience
The following adverse reactions have been identified during post-approval use of FOSAMAX and Fosamax Plus D. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Body as a Whole: hypersensitivity reactions including urticaria and rarely angioedema. Transient symptoms of myalgia, malaise, asthenia and rarely, fever have been reported with alendronate, typically in association with initiation of treatment. Rarely, symptomatic hypocalcemia has occurred, generally in association with predisposing conditions. Rarely, peripheral edema.
Gastrointestinal: esophagitis, esophageal erosions, esophageal ulcers, rarely esophageal stricture or perforation, and oropharyngeal ulceration. Gastric or duodenal ulcers, some severe and with complications have also been reported [see Dosage and Administration (2.3); Warnings and Precautions (5.1); Medication Guide].
Localized osteonecrosis of the jaw, generally associated with tooth extraction and/or local infection with delayed healing, has been reported rarely [see Warnings and Precautions (5.4)].
Musculoskeletal: bone, joint, and/or muscle pain, occasionally severe, and rarely incapacitating [see Warnings and Precautions (5.3)]; joint swelling; low-energy femoral shaft and subtrochanteric fractures [see Warnings and Precautions (5.5)].
Nervous System: dizziness and vertigo.
Skin: rash (occasionally with photosensitivity), pruritus, alopecia, rarely severe skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis.
Special Senses: rarely uveitis, scleritis or episcleritis.
Drug Interactions
Calcium Supplements/Antacids
It is likely that calcium supplements, antacids, and some oral medications will interfere with absorption of alendronate. Therefore, patients must wait at least one-half hour after taking Fosamax Plus D before taking any other oral medications.
Aspirin
In clinical studies, the incidence of upper gastrointestinal adverse events was increased in patients receiving concomitant therapy with daily doses of FOSAMAX greater than 10 mg and aspirin-containing products.
Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)
Fosamax Plus D may be administered to patients taking NSAIDs. In a 3-year, controlled, clinical study (n=2027) during which a majority of patients received concomitant NSAIDs, the incidence of upper gastrointestinal adverse events was similar in patients taking FOSAMAX 5 or 10 mg/day compared to those taking placebo. However, since NSAID use is associated with gastrointestinal irritation, caution should be used during concomitant use with Fosamax Plus D.
Drugs that May Impair the Absorption of Cholecalciferol
Olestra, mineral oils, orlistat, and bile acid sequestrants (e.g., cholestyramine, colestipol) may impair the absorption of vitamin D. Additional vitamin D supplementation should be considered [see Clinical Pharmacology (12.3)].
Drugs that May Increase the Catabolism of Cholecalciferol
Anticonvulsants, cimetidine, and thiazides may increase the catabolism of vitamin D. Additional vitamin D supplementation should be considered [see Clinical Pharmacology (12.3)].
USE IN SPECIFIC POPULATIONS
Pregnancy
Pregnancy Category C:
Alendronate Sodium
Reproduction studies in rats showed decreased postimplantation survival at 2 mg/kg/day and decreased body weight gain in normal pups at 1 mg/kg/day. Sites of incomplete fetal ossification were statistically significantly increased in rats beginning at 10 mg/kg/day in vertebral (cervical, thoracic, and lumbar), skull, and sternebral bones. The above doses ranged from one time (1 mg/kg) to 10 times (10 mg/kg) a maximum recommended daily dose of 10 mg/day based on surface area, mg/m2. No similar fetal effects were seen when pregnant rabbits were treated at doses up to 35 mg/kg/day (40 times a 10 mg human daily dose based on surface area, mg/m2).
Both total and ionized calcium decreased in pregnant rats at 15 mg/kg/day (13 times a 10-mg human daily dose based on surface area, mg/m2) resulting in delays and failures of delivery. Protracted parturition due to maternal hypocalcemia occurred in rats at doses as low as 0.5 mg/kg/day (0.5 times a 10 mg human daily dose based on surface area, mg/m2) when rats were treated from before mating through gestation. Maternotoxicity (late pregnancy deaths) occurred in the female rats treated with 15 mg/kg/day for varying periods of time ranging from treatment only during pre-mating to treatment only during early, middle, or late gestation; these deaths were lessened but not eliminated by cessation of treatment. Calcium supplementation either in the drinking water or by minipump could not ameliorate the hypocalcemia or prevent maternal and neonatal deaths due to delays in delivery; calcium supplementation IV prevented maternal, but not fetal deaths.
Bisphosphonates are incorporated into the bone matrix, from which they are gradually released over a period of years. The amount of bisphosphonate incorporated into adult bone, and hence, the amount available for release back into the systemic circulation, is directly related to the dose and duration of bisphosphonate use. There are no data on fetal risk in humans. However, there is a theoretical risk of fetal harm, predominantly skeletal, if a woman becomes pregnant after completing a course of bisphosphonate therapy. The impact of variables such as time between cessation of bisphosphonate therapy to conception, the particular bisphosphonate used, and the route of administration (intravenous versus oral) on the risk has not been studied.
Cholecalciferol
No data are available for cholecalciferol (vitamin D3). Administration of high doses (≥10,000 IU/every other day) of ergocalciferol (vitamin D2) to pregnant rabbits resulted in abortions and an increased incidence of fetal aortic stenosis. Administration of vitamin D2 (40,000 IU/day) to pregnant rats resulted in neonatal death, decreased fetal weight, and impaired osteogenesis of long bones postnatally.
There are no studies in pregnant women. Fosamax Plus D should be used during pregnancy only if the potential benefit justifies the potential risk to the mother and fetus.
Nursing Mothers
Cholecalciferol and some of its active metabolites pass into breast milk. It is not known whether alendronate is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Fosamax Plus D is administered to nursing women.
Pediatric Use
Fosamax Plus D is not indicated for use in children.
The efficacy and safety of alendronate were examined in a randomized, double-blind, placebo-controlled two-year study of 139 pediatric patients, aged 4-18 years, with severe osteogenesis imperfecta. One-hundred-and-nine patients were randomized to 5 mg alendronate daily (weight <40 kg) or 10 mg alendronate daily (weight ≥40 kg) and 30 patients to placebo. The mean baseline lumbar spine BMD Z-score of the patients was -4.5. The mean change in lumbar spine BMD Z-score from baseline to Month 24 was 1.3 in the alendronate-treated patients and 0.1 in the placebo-treated patients. Treatment with alendronate did not reduce the risk of fracture. Sixteen percent of the alendronate patients who sustained a radiologically-confirmed fracture by Month 12 of the study had delayed fracture healing (callus remodeling) or fracture non-union when assessed radiographically at Month 24 compared with 9% of the placebo-treated patients. In alendronate-treated patients, bone histomorphometry data obtained at Month 24 demonstrated decreased bone turnover and delayed mineralization time; however, there were no mineralization defects. There were no statistically significant differences between the alendronate and placebo groups in reduction of bone pain.
Geriatric Use
Of the patients receiving FOSAMAX in the Fracture Intervention Trial (FIT), 71% (n=2302) were ≥65 years of age and 17% (n=550) were ≥75 years of age. Of the patients receiving FOSAMAX in the United States and Multinational osteoporosis treatment studies in women, and osteoporosis studies in men [see Clinical Studies (14.1, 14.2)], 45% and 54%, respectively, were 65 years of age or over. No overall differences in efficacy or safety were observed between these patients and younger patients, but greater sensitivity of some older individuals cannot be ruled out. Dietary requirements of vitamin D3 are increased in the elderly.
Overdosage
Alendronate Sodium
Significant lethality after single oral doses with alendronate was seen in female rats and mice at 552 mg/kg (3256 mg/m2) and 966 mg/kg (2898 mg/m2), respectively. In males, these values were slightly higher, 626 and 1280 mg/kg, respectively. There was no lethality in dogs at oral doses up to 200 mg/kg (4000 mg/m2).
No specific information is available on the treatment of overdosage with alendronate. Hypocalcemia, hypophosphatemia, and upper gastrointestinal adverse events, such as upset stomach, heartburn, esophagitis, gastritis, or ulcer, may result from oral overdosage. Milk or antacids should be given to bind alendronate. Due to the risk of esophageal irritation, vomiting should not be induced and the patient should remain fully upright.
Dialysis would not be beneficial.
Cholecalciferol
Significant lethality occurred in mice treated with a single high oral dose of calcitriol (4 mg/kg), the hormonal metabolite of cholecalciferol.
There is limited information regarding doses of cholecalciferol associated with acute toxicity, although intermittent (yearly or twice yearly) single doses of ergocalciferol (vitamin D2) as high as 600,000 IU have been given without reports of toxicity. Signs and symptoms of vitamin D toxicity include hypercalcemia, hypercalciuria, anorexia, nausea, vomiting, polyuria, polydipsia, weakness, and lethargy. Serum and urine calcium levels should be monitored in patients with suspected vitamin D toxicity. Standard therapy includes restriction of dietary calcium, hydration, and systemic glucocorticoids in patients with severe hypercalcemia.
Dialysis to remove vitamin D would not be beneficial.
Fosamax Plus D Description
Fosamax Plus D contains alendronate sodium, a bisphosphonate, and cholecalciferol (vitamin D3).
Alendronate sodium is a bisphosphonate that acts as a specific inhibitor of osteoclast-mediated bone resorption. Bisphosphonates are synthetic analogs of pyrophosphate that bind to the hydroxyapatite found in bone.
Alendronate sodium is chemically described as (4-amino-1-hydroxybutylidene) bisphosphonic acid monosodium salt trihydrate.
The empirical formula of alendronate sodium is C4H12NNaO7P2•3H2O and its formula weight is 325.12. The structural formula is:
Alendronate sodium is a white, crystalline, nonhygroscopic powder. It is soluble in water, very slightly soluble in alcohol, and practically insoluble in chloroform.
Cholecalciferol (vitamin D3) is a secosterol that is the natural precursor of the calcium-regulating hormone calcitriol (1,25 dihydroxyvitamin D3).
The chemical name of cholecalciferol is (3β,5Z,7E)-9,10-secocholesta-5,7,10(19)-trien-3-ol. The empirical formula of cholecalciferol is C27H44O and its molecular weight is 384.6. The structural formula is:
Cholecalciferol is a white, crystalline, odorless powder. Cholecalciferol is practically insoluble in water, freely soluble in usual organic solvents, and slightly soluble in vegetable oils.
Fosamax Plus D for oral administration contains 91.37 mg of alendronate monosodium salt trihydrate, the molar equivalent of 70 mg of free acid, and 70 or 140 mcg of cholecalciferol, equivalent to 2800 or 5600 International Units (IU) vitamin D, respectively. Each tablet contains the following inactive ingredients: microcrystalline cellulose, lactose anhydrous, medium chain triglycerides, gelatin, croscarmellose sodium, sucrose, colloidal silicon dioxide, magnesium stearate, butylated hydroxytoluene, modified food starch, and sodium aluminum silicate.
Fosamax Plus D - Clinical Pharmacology
Mechanism of Action
Alendronate Sodium
Animal studies have indicated the following mode of action. At the cellular level, alendronate shows preferential localization to sites of bone resorption, specifically under osteoclasts. The osteoclasts adhere normally to the bone surface but lack the ruffled border that is indicative of active resorption. Alendronate does not interfere with osteoclast recruitment or attachment, but it does inhibit osteoclast activity. Studies in mice on the localization of radioactive [3H]alendronate in bone showed about 10‑fold higher uptake on osteoclast surfaces than on osteoblast surfaces. Bones examined 6 and 49 days after [3H]alendronate administration in rats and mice, respectively, showed that normal bone was formed on top of the alendronate, which was incorporated inside the matrix. While incorporated in bone matrix, alendronate is not pharmacologically active. Thus, alendronate must be continuously administered to suppress osteoclasts on newly formed resorption surfaces. Histomorphometry in baboons and rats showed that alendronate treatment reduces bone turnover (i.e., the number of sites at which bone is remodeled). In addition, bone formation exceeds bone resorption at these remodeling sites, leading to progressive gains in bone mass.
Cholecalciferol
Vitamin D3 is produced in the skin by photochemical conversion of 7-dehydrocholesterol to previtamin D3 by ultraviolet light. This is followed by non-enzymatic isomerization to vitamin D3. In the absence of adequate sunlight exposure, vitamin D3 is an essential dietary nutrient. Vitamin D3 in skin and dietary vitamin D3 (absorbed into chylomicrons) is converted to 25‑hydroxyvitamin D3 in the liver. Conversion to the active calcium-mobilizing hormone 1,25-dihydroxyvitamin D3 (calcitriol) in the kidney is stimulated by both parathyroid hormone and hypophosphatemia. The principal action of 1,25‑dihydroxyvitamin D3 is to increase intestinal absorption of both calcium and phosphate as well as regulate serum calcium, renal calcium and phosphate excretion, bone formation and bone resorption.
Vitamin D is required for normal bone formation. Vitamin D insufficiency develops when both sunlight exposure and dietary intake are inadequate. Insufficiency is associated with negative calcium balance, increased parathyroid hormone levels, bone loss, and increased risk of skeletal fracture. In severe cases, deficiency results in more severe hyperparathyroidism, hypophosphatemia, proximal muscle weakness, bone pain and osteomalacia.
Pharmacodynamics
Alendronate Sodium
Alendronate is a bisphosphonate that binds to bone hydroxyapatite and specifically inhibits the activity of osteoclasts, the bone-resorbing cells. Alendronate reduces bone resorption with no direct effect on bone formation, although the latter process is ultimately reduced because bone resorption and formation are coupled during bone turnover.
Daily oral doses of alendronate (5, 20, and 40 mg for six weeks) in postmenopausal women produced biochemical changes indicative of dose-dependent inhibition of bone resorption, including decreases in urinary calcium and urinary markers of bone collagen degradation (such as deoxypyridinoline and cross-linked N‑telopeptides of type I collagen). These biochemical changes tended to return toward baseline values as early as 3 weeks following the discontinuation of therapy with alendronate and did not differ from placebo after 7 months.
Long-term treatment of osteoporosis with FOSAMAX 10 mg/day (for up to five years) reduced urinary excretion of markers of bone resorption, deoxypyridinoline and cross-linked N‑telopeptides of type l collagen, by approximately 50% and 70%, respectively, to reach levels similar to those seen in healthy premenopausal women. The decrease in the rate of bone resorption indicated by these markers was evident as early as one month and at three to six months reached a plateau that was maintained for the entire duration of treatment with FOSAMAX. In osteoporosis treatment studies FOSAMAX 10 mg/day decreased the markers of bone formation, osteocalcin and bone specific alkaline phosphatase by approximately 50%, and total serum alkaline phosphatase by approximately 25 to 30% to reach a plateau after 6 to 12 months. Similar reductions in the rate of bone turnover were observed in postmenopausal women during one-year studies with once weekly FOSAMAX 70 mg for the treatment of osteoporosis. These data indicate that the rate of bone turnover reached a new steady-state, despite the progressive increase in the total amount of alendronate deposited within bone.
As a result of inhibition of bone resorption, asymptomatic reductions in serum calcium and phosphate concentrations were also observed following treatment with FOSAMAX. In the long-term studies, reductions from baseline in serum calcium (approximately 2%) and phosphate (approximately 4 to 6%) were evident the first month after the initiation of FOSAMAX 10 mg. No further decreases in serum calcium were observed for the five-year duration of treatment; however, serum phosphate returned toward prestudy levels during years three through five. In one-year studies with once weekly FOSAMAX 70 mg, similar reductions were observed at 6 and 12 months. The reduction in serum phosphate may reflect not only the positive bone mineral balance due to FOSAMAX but also a decrease in renal phosphate reabsorption.
Osteoporosis in Men
Treatment of men with osteoporosis with FOSAMAX 10 mg/day for two years reduced urinary excretion of cross-linked N-telopeptides of type I collagen by approximately 60% and bone-specific alkaline phosphatase by approximately 40%. Similar reductions were observed in a one-year study in men with osteoporosis receiving once weekly FOSAMAX 70 mg.
Cholecalciferol
Vitamin D is required for normal bone formation. Vitamin D insufficiency is associated with negative calcium balance, leading to increased parathyroid hormone levels and worsening of bone loss associated with osteoporosis. When taken without vitamin D, alendronate is also associated with a reduction in serum calcium concentrations and increased parathyroid hormone levels. In a 15‑week trial, 717 postmenopausal women and men, mean age 67 years, with osteoporosis (lumbar spine bone mineral density [BMD] of at least 2.5 standard deviations below the premenopausal mean) were randomized to receive either weekly Fosamax Plus D 70 mg/2800 IU vitamin D or weekly FOSAMAX 70 mg alone with no vitamin D supplementation. Patients who were vitamin D deficient (25‑hydroxyvitamin D <9 ng/mL) at baseline were excluded. Treatment with FOSAMAX PLUS D 70 mg/2800 IU resulted in a smaller reduction in serum calcium levels (-0.9%) when compared to FOSAMAX 70 mg alone (-1.4%). As well, treatment with Fosamax Plus D 70 mg/2800 IU resulted in a significantly smaller increase in parathyroid hormone levels when compared to FOSAMAX 70 mg alone (14% and 24%, respectively).
The sufficiency of patients’ vitamin D status is best assessed by measuring 25-hydroxyvitamin D levels. In the 15‑week trial mentioned above, baseline 25-hydroxyvitamin D levels were 22.2 ng/mL in the Fosamax Plus D group and 22.1 ng/mL in the FOSAMAX only group. After 15 weeks of treatment, the mean levels were 23.1 ng/mL and 18.4 ng/mL in the Fosamax Plus D and FOSAMAX only groups, respectively. The final levels of 25-hydroxyvitamin D at Week 15 are summarized in Table 4.
| Number (%) of Patients | ||||||
| ||||||
| 25-hydroxyvitamin D Ranges (ng/mL) | <9 | 9-14 | 15-19 | 20-24 | 25-29 | 30-62 |
| Fosamax Plus D (70 mg/2800 IU) (N=357) | 4 (1.1) | 37 (10.4) | 87 (24.4) | 84 (23.5) | 82 (23.0) | 63 (17.7) |
| FOSAMAX 70 mg (N=351) | 46 (13.1) | |||||
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