Drug Interaction Report

MONITOR: Administration of technetium (Tc 99m) oxidronate after chelating agents, diphosphonates, tetracyclines, or iron containing drugs may reduce the quality of the scintigraphic procedure by decreasing the accumulation of Tc 99m oxidronate in skeletal bone. The exact mechanism of the interaction is unknown; however, it may be related to the effects of the interacting drugs on bone homeostasis.

MANAGEMENT: Proceed with caution if chelating agents, diphosphonates, tetracyclines, and iron-containing drugs are used prior to technetium (Tc 99m) oxidronate. The quality of the resulting imaging may be reduced.

ADJUST DOSING INTERVAL: Food significantly decreases the bioavailability of risedronate, possibly to negligible levels.

MANAGEMENT: Risedronate should be administered with 180 to 240 mL (6 to 8 ounces) of plain water, at least 30 minutes before the first food, beverage, or medication of the day. Patients should remain upright for at least 30 minutes following administration of risedronate.