(also see CLINICAL PHARMACOLOGY, Pharmacokinetics, Drug Interactions)
Estrogen/hormone replacement therapy (HRT)
Concomitant use of HRT (estrogen ± progestin) and alendronate sodium was assessed in two clinical studies of one or two years' duration in postmenopausal osteoporotic women. In these studies, the safety and tolerability profile of the combination was consistent with those of the individual treatments; however, the degree of suppression of bone turnover (as assessed by mineralizing surface) was significantly greater with the combination than with either component alone. The long-term effects of combined alendronate sodium and HRT on fracture occurrence have not been studied (see CLINICAL PHARMACOLOGY, Clinical Studies, Concomitant use with estrogen/hormone replacement therapy (HRT) and ADVERSE REACTIONS, Clinical Studies, Concomitant use with estrogen/hormone replacement therapy).
Significant lethality after single oral doses 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 sodium. 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.