How Much Does Risedronate Cost in Mexico vs the USA?

Risedronate sodium delayed-release tablets are bisphosphonate in a delayed-release formulation and is indicated for treatment of postmenopausal osteoporosis (1.1) Limitations of Use Optimal duration of use has not been determined. For patients at low-risk for fracture, consider drug discontinuation after 3 to 5 years of use (1.2). 1.1 Postmenopausal Osteoporosis Risedronate sodium delayed-release tablets are indicated for the treatment of osteoporosis in postmenopausal women. In postmenopausal women, risedronate sodium has been shown to reduce the incidence of vertebral fractures and a composite endpoint of nonvertebral osteoporosis-related fractures [ see Clinical Studies (14.1) ]. 1.2 Important Limitations of Use The optimal duration of use has not been determined. The safety and effectiveness of risedronate sodium delayed-release tablets for the treatment of osteoporosis are based on clinical data of one year duration. All patients on bisphosphonate therapy should have the need for continued therapy re-evaluated on a periodic basis. Patients at low-risk for fracture should be considered for drug discontinuation after 3 to 5 years of use. Patients who discontinue therapy should have their risk for fracture re-evaluated periodically.

One 35 mg delayed-release tablet once-a-week (2.1) Instruct patients to: • Take risedronate sodium delayed-release tablets in the morning immediately following breakfast with at least 4 ounces of plain water (2.2) • Avoid lying down for 30 minutes after taking risedronate sodium delayed-release tablets (2.2) • Take supplemental calcium and vitamin D if dietary intake is inadequate (2.3) 2.1 Treatment of Postmenopausal Osteoporosis [ see Indications and Usage (1.1) ] The recommended regimen is: • one 35 mg delayed-release tablet orally, taken once-a-week [see Indications and Usage (1.1)] 2.2 Important Administration Instructions Instruct patients to do the following: • Take risedronate sodium delayed-release tablets in the morning immediately following breakfast. Risedronate sodium delayed-release tablets should be taken immediately following breakfast and not under fasting conditions because of a higher risk of abdominal pain if taken before breakfast when fasting. • Swallow risedronate sodium delayed-release tablets whole while in an upright position and with at least 4 ounces of plain water to facilitate delivery to the stomach. Avoid lying down for 30 minutes after taking the medication [ see Warnings and Precautions (5.2) ]. • Do not chew, cut, or crush risedronate sodium delayed-release tablets. 2.3 Recommendations for Calcium and Vitamin D Supplementation Instruct patients to take supplemental calcium and vitamin D if dietary intake is inadequate [ see Warnings and Precautions (5.3) ] and to take calcium supplements, antacids, magnesium-based supplements or laxatives, and iron preparations at a different time of the day as they interfere with the absorption of risedronate sodium delayed-release tablets. 2.4 Administration Instructions for Missed Doses If the once-weekly dose is missed, instruct patients to take one tablet on the morning after they remember and return to taking one tablet once-a-week, as originally scheduled on their chosen day. Patients should not take two tablets on the same day.

Risedronate sodium delayed-release tablets contraindicated in patients with the following conditions: 1. Abnormalities of the esophagus which delay esophageal emptying such as stricture or achalasia [ see Warnings and Precautions (5.2) ] 2. Inability to stand or sit upright for at least 30 minutes [ see Dosage and Administration (2), Warnings and Precautions (5.2) ] 3. Hypocalcemia [ see Warnings and Precautions (5.3) ] 4. Known hypersensitivity to any component of this product. Angioedema, generalized rash, bullous skin reactions, Stevens-Johnson syndrome and toxic epidermal necrolysis, have been reported [ see Adverse Reactions (6.2) ] • Abnormalities of the esophagus which delay esophageal emptying such as stricture or achalasia (4, 5.2) • Inability to stand or sit upright for at least 30 minutes (4, 5.2) • Hypocalcemia (4, 5.3) • Known hypersensitivity to any component of this product (4, 6.2)

• Products Containing Same Active Ingredient : Patients receiving Actonel should not be treated with risedronate sodium delayed-release tablets (5.1) • Upper Gastrointestinal Adverse Reactions can occur. Instruct patients to follow dosing instructions. Discontinue use if new or worsening symptoms occur (5.2) • Hypocalcemia may worsen and must be corrected prior to use (5.3) • Osteonecrosis of the Jaw has been reported (5.4) • Severe Bone, Joint, Muscle Pain may occur. Discontinue use if severe symptoms develop (5.5, 6.2) • Atypical Femur Fractures have been reported. Patients with new thigh or groin pain should be evaluated to rule out a femoral fracture (5.6) 5.1 Drug Products with the Same Active Ingredient Risedronate sodium delayed-release tablets contain the same active ingredient found in Actonel ® . A patient being treated with Actonel should not receive risedronate sodium delayed-release tablets. 5.2 Upper Gastrointestinal Adverse Reactions Risedronate sodium, 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 risedronate sodium is given to patients with active upper gastrointestinal problems (such as known Barrett’s esophagus, dysphagia, other esophageal diseases, gastritis, duodenitis or ulcers) [ see Contraindications (4), Adverse Reactions (6.1), Information for Patients (17) ]. 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. 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 risedronate sodium 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 and/or who fail to swallow it with the recommended 4 ounces of water, and/or who continue to take oral bisphosphonates 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) ]. In patients who cannot comply with dosing instructions due to mental disability, therapy with risedronate sodium 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. 5.3 Mineral Metabolism Hypocalcemia has been reported in patients taking risedronate sodium delayed-release tablets. Treat hypocalcemia and other disturbances of bone and mineral metabolism should be effectively treated before starting risedronate sodium therapy. Instruct patients to take supplemental calcium and vitamin D if their dietary intake is inadequate. Adequate intake of calcium and vitamin D is important in all patients [ see Contraindications (4), Adverse Reactions (6.1), Information for Patients (17) ]. 5.4 Jaw Osteonecrosis 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 risedronate. Known risk factors for osteonecrosis of the jaw include invasive dental procedures (for example, tooth extraction, dental implants, boney surgery), diagnosis of cancer, concomitant therapies (for example, chemotherapy, corticosteroids, angiogenesis inhibitors), poor oral hygiene, and co-morbid disorders (for example, periodontal and/or other pre-existing dental disease, anemia, coagulopathy, infection, ill-fitting dentures). The risk of ONJ may increase with duration of exposure to bisphosphonates. 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 ONJ 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 [ see Adverse Reactions (6.2) ]. 5.5 Musculoskeletal Pain In postmarketing experience, there have been reports of severe and occasionally incapacitating bone, joint, and/or muscle pain in patients taking bisphosphonates [ see Adverse Reactions (6.2) ]. The time to onset of symptoms varied from one day to several months after starting the drug. Most patients had relief of symptoms after stopping medication. A subset had recurrence of symptoms when rechallenged with the same drug or another bisphosphonate. Consider discontinuing use if severe symptoms develop. 5.6 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 traverse 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 (for example, 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. 5.7 Renal Impairment Risedronate sodium is not recommended for use in patients with severe renal impairment (creatinine clearance less than 30 mL/min) because of lack of clinical experience. 5.8 Laboratory Test Interactions Bisphosphonates are known to interfere with the use of bone-imaging agents. Specific studies with risedronate sodium have not been performed.

Risedronate is not metabolized and does not induce or inhibit hepatic microsomal drug-metabolizing enzymes (for example, Cytochrome P450). Calcium supplements, antacids, proton pump inhibitors (PPIs), H 2 blockers, magnesium-based supplements or laxatives, and iron preparations interfere with the absorption of risedronate sodium (7.1, 7.2) 7.1 Calcium Supplements/Antacids When risedronate sodium was administered following breakfast, the co-administration of a tablet containing 600 mg of elemental calcium and 400 international units vitamin D reduced risedronate bioavailability by approximately 38% [ see Clinical Pharmacology (12.3) ]. Calcium supplements, antacids, magnesium-based supplements or laxatives, and iron preparations interfere with the absorption of risedronate sodium and should not be taken together. 7.2 Histamine 2 (H 2 ) Blockers and Proton Pump Inhibitors (PPIs) Drugs that raise stomach pH (for example, PPIs or H 2 blockers) may cause faster drug release from enteric coated (delayed-release) drug products such as risedronate sodium. Co-administration of risedronate sodium with the PPI, esomeprazole, increased risedronate bioavailability. The maximum plasma concentration (C max ) and the area under the plasma concentration (AUC) were increased by 60 percent and 22 percent, respectively. Concomitant administration of risedronate sodium and H 2 blockers or PPIs is not recommended. 7.3 Hormone Therapy Concomitant use of risedronate sodium with estrogens and estrogen agonist/antagonists has not been studied. 7.4 Aspirin/Nonsteroidal Anti-Inflammatory Drugs In the Phase 3 study comparing risedronate sodium 35 mg once-a-week immediately following breakfast and risedronate sodium 5 mg daily, 18% of NSAID users (any use) in both groups developed upper gastrointestinal adverse reactions. Among non-users, 13% of patients taking risedronate sodium 35 mg once-a-week immediately following breakfast developed upper gastrointestinal adverse reactions, compared to 12% taking risedronate sodium 5 mg daily.

Most common adverse reactions (greater than 5%) include: diarrhea, influenza, arthralgia, back pain, and abdominal pain (6.1) Hypersensitivity reactions (angioedema, generalized rash, bullous skin reactions, Stevens-Johnson syndrome, and toxic epidermal necrolysis), and eye inflammation (iritis, uveitis) have been reported rarely (6.2) To report SUSPECTED ADVERSE REACTIONS, contact Sun Pharmaceutical Industries Inc. at 1-800-818-4555 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Studies 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. Treatment of Postmenopausal Osteoporosis Once-a-Week Dosing with Risedronate Sodium Delayed-Release tablets The safety of risedronate sodium delayed-release 35 mg once-a-week in the treatment of postmenopausal osteoporosis was assessed in a 1-year, double-blind, multicenter study comparing risedronate sodium delayed-release 35 mg once-a-week to risedronate sodium immediate-release 5 mg daily in postmenopausal women 50 years of age or older. Risedronate sodium delayed-release was administered either at least 30 minutes before (N = 308) or immediately following (N = 307) breakfast, and risedronate sodium immediate-release 5 mg daily (N = 307) was administered at least 30 minutes before breakfast. Patients with pre-existing gastrointestinal disease and concomitant use of non-steroidal anti-inflammatory drugs, proton pump inhibitors, and H 2 antagonists were included in this clinical trial. All women received daily supplementation with 1000 mg of elemental calcium plus 800 to 1000 international units vitamin D. As treatment with risedronate sodium resulted in a significantly higher incidence of abdominal pain when administered before breakfast under fasting conditions, safety results that follow refer only to risedronate sodium delayed-release 35 mg once-a-week immediately following breakfast and risedronate sodium immediate-release 5 mg daily. The incidence of all-cause mortality was 0.0% in the risedronate sodium delayed-release 35 mg once-a-week group and 0.3% in the risedronate sodium immediate-release 5 mg daily group. The incidence of serious adverse reactions was 6.5% in the risedronate sodium delayed-release 35 mg once-a-week group and 7.2% in the risedronate sodium immediate-release 5 mg daily group. The percentage of patients who withdrew from the study due to adverse reactions was 9.1% in the risedronate sodium delayed-release 35 mg once-a-week group and 8.1% in the risedronate sodium immediate-release 5 mg daily group. The overall safety and tolerability profiles of the two dosing regimens were similar. Table 1 lists adverse reactions reported in greater than or equal to 2% of patients. Adverse reactions are shown without attribution of causality. Table 1 Adverse Reactions Occurring at a Frequency of greater than or equal to 2% in Either Treatment Group System Organ Class Preferred Term 35 mg Risedronate sodium Delayed-release Weekly N = 307% 5 mg Risedronate sodium Immediate-release Daily N = 307% Gastrointestinal disorders Diarrhea 8.8 4.9 Abdominal pain 5.2 2.9 Constipation 4.9 2.9 Vomiting 4.9 1.6 Dyspepsia 3.9 3.9 Nausea 3.6 3.9 Abdominal pain upper 2.9 2.3 Infections and infestations Influenza 7.2 6.2 Bronchitis 3.9 4.2 Upper respiratory tract infection 3.6 2.6 Musculoskeletal and connective tissue disorders Arthralgia 6.8 7.8 Back pain 6.8 5.9 Pain in extremity 3.9 2.3 Musculoskeletal pain 2.0 1.6 Muscle spasms 1.0 2.3 Nervous system disorders Dizziness 2.6 3.3 Headache 2.6 4.9 Acute Phase Reactions: Symptoms consistent with acute phase reaction have been reported with bisphosphonate use. The overall incidence of acute phase reaction was 2.3% in the risedronate sodium delayed-release 35 mg once-a-week group and 1.3% in the risedronate sodium immediate-release 5 mg daily group. These incidence rates are based on reporting of one or more pre-specified acute phase reaction-like symptoms within 3 days of the first dose and for a duration of 7 days or less. Gastrointestinal Adverse Reactions : Adverse reactions related to the upper gastrointestinal tract occurred in 16% of subjects treated with risedronate sodium delayed-release 35 mg once-a-week and 15% of subjects treated with risedronate sodium immediate-release 5 mg daily. The incidence of upper gastrointestinal tract adverse reactions in the risedronate sodium delayed-release 35 mg once-a-week and risedronate sodium immediate-release 5 mg daily groups were: abdominal pain (5.2% versus 2.9%), dyspepsia (3.9% versus 3.9%), upper abdominal pain (2.9% versus 2.3%), gastritis (1.0% versus 1.0%), and gastroesophageal reflux disease (1.0% versus 1.6%). Study discontinuation due to abdominal pain occurred in 1.3% of the risedronate sodium delayed-release 35 mg once-a-week group and 0.7% of the risedronate sodium immediate-release 5 mg daily group. Musculoskeletal Adverse Reactions: Selected musculoskeletal adverse reactions were reported in 16% of subjects treated with risedronate sodium delayed-release 35 mg once-a-week and 15% of subjects treated with risedronate sodium immediate-release 5 mg daily. The incidence of musculoskeletal adverse reactions in the risedronate sodium delayed-release 35 mg once-a-week and risedronate sodium immediate-release 5 mg daily groups were: arthralgia (6.8% versus 7.8%), back pain (6.8% versus 5.9%), musculoskeletal pain (2.0% versus 1.6%), and myalgia (1.3% versus 1.0%). Laboratory Test Findings : Parathyroid hormone: The effect of risedronate sodium delayed-release 35 mg once-a-week and risedronate sodium immediate-release 5 mg daily on parathyroid hormone was evaluated in postmenopausal women with osteoporosis. At week 52, in subjects with normal levels at baseline, PTH levels greater than 65 pg/mL (upper limit of normal) were noted in 9% of subjects receiving risedronate sodium delayed-release 35 mg once-a-week and 8% of subjects receiving risedronate sodium immediate-release 5 mg daily. In subjects with normal levels at baseline, PTH levels greater than 97 pg/mL (1.5 times the upper limit of normal) were seen in 2% of subjects receiving risedronate sodium delayed-release 35 mg once-a-week and no subjects receiving risedronate sodium immediate-release 5 mg daily. There were no clinically significant differences between treatment groups for levels of calcium, phosphorus and magnesium. Daily Dosing with Risedronate Sodium Immediate-Release 5 mg tablets The safety of risedronate sodium immediate-release 5 mg once daily in the treatment of postmenopausal osteoporosis was assessed in four randomized, double-blind, placebo-controlled multinational trials of 3232 women aged 38 to 85 years with postmenopausal osteoporosis. The duration of the trials was up to three years, with 1619 patients exposed to placebo and 1613 patients exposed to risedronate sodium immediate-release 5 mg daily. Patients with pre-existing gastrointestinal disease and concomitant use of non-steroidal anti-inflammatory drugs, proton pump inhibitors (PPIs), and H 2 antagonists were included in these clinical trials. All women received 1000 mg of elemental calcium plus vitamin D supplementation up to 500 international units per day if their 25-hydroxyvitamin D 3 level was below normal at baseline. The incidence of all-cause mortality was 2.0% in the placebo group and 1.7% in the risedronate sodium immediate-release 5 mg daily group. The incidence of serious adverse reactions was 24.6% in the placebo group and 27.2% in the risedronate sodium immediate-release 5 mg daily group. The percentage of patients who withdrew from the study due to adverse reactions was 15.6% in the placebo group and 14.8% in the risedronate sodium immediate-release 5 mg daily group. The most common adverse reactions reported in greater than 10% of subjects were: back pain, arthralgia, abdominal pain and dyspepsia. Gastrointestinal Adverse Reactions: The incidence of adverse reactions in the placebo and risedronate sodium immediate-release 5 mg daily groups were: abdominal pain (9.9% versus 12.2%), diarrhea (10.0% versus 10.8%), dyspepsia (10.6% versus 10.8%), and gastritis (2.3% versus 2.7%). Duodenitis and glossitis have been reported uncommonly in the risedronate sodium immediate-release 5 mg daily group (0.1% to 1%). In patients with active upper gastrointestinal disease at baseline, the incidence of upper gastrointestinal adverse reactions was similar between the placebo and risedronate sodium immediate-release 5 mg daily groups. Musculoskeletal Adverse Reactions: The incidence of adverse reactions in the placebo and risedronate sodium immediate-release 5 mg daily groups were: back pain (26.1% versus 28.0%), arthralgia (22.1% versus 23.7%), myalgia (6.2% versus 6.7%), and bone pain (4.8% versus 5.3%). Laboratory Test Findings : Throughout the Phase 3 studies, transient decreases from baseline in serum calcium (less than 1%) and serum phosphate (less than 3%) and compensatory increases in serum PTH levels (less than 30%) were observed within 6 months in patients in osteoporosis clinical trials treated with risedronate sodium immediate-release 5 mg daily. There were no significant differences in serum calcium, phosphate, or PTH levels between placebo and risedronate sodium immediate-release 5 mg daily at 3 years. Serum calcium levels below 8 mg/dL were observed in 18 patients, 9 (0.5%) in each treatment arm (placebo and risedronate sodium immediate-release 5 mg daily). Serum phosphorus levels below 2 mg/dL were observed in 14 patients, 3 (0.2%) treated with placebo and 11 (0.6%) treated with risedronate sodium immediate-release 5 mg daily. There have been rare reports (less than 0.1%) of abnormal liver function tests. Endoscopic Findings : In the risedronate sodium immediate-release 5 mg daily clinical trials, endoscopic evaluation was encouraged in any patient with moderate-to-severe gastrointestinal complaints, while maintaining the blind. Endoscopies were performed on equal numbers of patients between the placebo and treated groups [75 (14.5%) placebo; 75 (11.9%) risedronate sodium immediate-release 5 mg daily]. Clinically important findings (perforations, ulcers, or bleeding) among this symptomatic population were similar between groups (51% placebo; 39% risedronate sodium immediate-release 5 mg daily). 6.2 Postmarketing Experience The following adverse reactions have been reported with the use of risedronate sodium immediate-release. Because these adverse 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. Hypersensitivity Reactions Hypersensitivity and skin reactions have been reported, including angioedema, generalized rash, bullous skin reactions, Stevens-Johnson syndrome and toxic epidermal necrolysis. Gastrointestinal Adverse Reactions Reactions involving upper gastrointestinal irritation, such as esophagitis and esophageal or gastric ulcers, have been reported [ see Warnings and Precautions (5.2) ]. Musculoskeletal Pain Bone, joint, or muscle pain, described as severe or incapacitating, have been reported rarely [ see Warnings and Precautions (5.5) ]. Eye Inflammation Reactions of eye inflammation including iritis and uveitis have been reported rarely. Jaw Osteonecrosis Osteonecrosis of the jaw has been reported rarely [ see Warnings and Precautions (5.4) ]. Pulmonary Asthma exacerbations

8.1 Pregnancy Risk Summary Available data on use of risedronate sodium in pregnant women are insufficient to inform drug-associated risk of adverse maternal or fetal outcomes. Discontinue risedronate sodium when pregnancy is recognized. In animal reproduction studies, daily oral administration of risedronate to pregnant rats during organogenesis decreased neonatal survival and body weight at doses approximately 5 and 26 times, respectively, the highest recommended human daily dose of 30 mg (based on body surface area, mg/m 2 ), the dose indicated for treatment of Paget’s disease. A low incidence of cleft palate was observed in fetuses of dams treated at doses approximately equal to the 30 mg human daily dose. Delayed skeletal ossification was observed in fetuses of dams treated at approximately 2.5 to 5 times the 30 mg human daily dose. Periparturient mortality due to maternal hypocalcemia occurred in dams and neonates upon daily oral administration of risedronate to pregnant rats during mating and/or gestation starting at doses equivalent to the 30 mg daily human dose. Bisphosphonates are incorporated into the bone matrix, from which they are gradually released over a period of weeks to years. The amount of bisphosphonate incorporated into adult bone available for release into the systemic circulation is directly related to the dose and duration of bisphosphonate use. Consequently, 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. 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 this risk has not been studied. The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defects, loss, or other adverse outcomes. In the U.S. general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Data Animal data In animal studies, pregnant rats received risedronate sodium during organogenesis at doses 1 to 26 times the human Paget’s disease dose of 30 mg/day (based on body surface area, mg/m 2 ). Survival of neonates was decreased in rats treated during gestation with oral doses approximately 5 times the human dose and body weight was decreased in neonates from dams treated with approximately 26 times the human dose. A low incidence of cleft palate was observed in fetuses from female rats treated with oral doses approximately equal to the human dose. The number of fetuses exhibiting incomplete ossification of sternebrae or skull of dams treated with approximately 2.5 times the human dose was significantly increased compared to controls. Both incomplete ossification and unossified sternebrae were increased in fetuses of dams treated with oral doses approximately 5 times the human dose. No significant ossification effects were seen in fetuses of rabbits treated with oral doses approximately 7 times the human dose (the highest dose tested). However, 1 of 14 litters were aborted and 1 of 14 litters were delivered prematurely. Periparturient mortality due to maternal hypocalcemia occurred in dams and neonates when pregnant rats were treated daily during mating and/or gestation with oral doses equivalent to the human dose or higher.