Drug Interactions between Citracal Plus Bone Density Builder and mycophenolic acid

Limited data suggest that the oral bioavailability of mycophenolic acid (MPA) may be decreased by concomitant administration of iron preparations. The mechanism of interaction has not been established, and available data are conflicting. In an early study with seven healthy subjects, administration of 1 gram of mycophenolate mofetil (MMF) with a single 1050 mg dose of sustained-release ferrous sulfate (equivalent to 210 mg of elemental iron) decreased mean MPA peak plasma concentration (Cmax) and systemic exposure (AUC) by 94% and 91%, respectively, compared to administration of MMF alone. However, several subsequent studies, including some conducted in kidney transplant patients, reported no significant changes in MPA pharmacokinetics during coadministration with iron at the same time or up to four hours apart. The reasons for the discrepancy have not been determined. In vitro, there was no evidence of complexation between iron and MMF or MPA. No precautions appear necessary to avoid potential interaction; however, it may be advisable to monitor pharmacologic response and blood levels closely if an iron product is added to stabilized mycophenolate therapy.