Drug Interactions between Actonel with Calcium and cefuroxime

ADJUST DOSING INTERVAL: Coadministration with antacids or agents with acid-neutralizing effects may reduce the oral bioavailability of cefpodoxime proxetil and cefuroxime axetil. The proposed mechanism is a pH-dependent reduction in drug dissolution and absorption. In ten healthy volunteers, 10 mL of magnesium hydroxide-aluminum hydroxide (600 mg-900 mg) administered at 2 hours and at 15 minutes before the ingestion of cefpodoxime proxetil 200 mg led to an approximately 40% reduction in cefpodoxime peak plasma concentration (Cmax) and systemic exposure (AUC) compared to when the antibiotic was administered alone. Similar results were reported with sodium bicarbonate and aluminum hydroxide in another study. Likewise, pretreatment with ranitidine plus sodium bicarbonate decreased the Cmax and AUC of cefuroxime by over 40% in six healthy volunteers. The clinical significance of these effects is unknown, but potentially reduced antibiotic efficacy should be considered.

MANAGEMENT: Until further data are available, patients treated with cefpodoxime proxetil or cefuroxime axetil should avoid taking antacids or oral medications that contain antacids (e.g., didanosine buffered tablets or pediatric oral solution) for at least two hours before and after administration of the antibiotic.

ADJUST DOSING INTERVAL: Products containing aluminum, calcium, magnesium and other polyvalent cations such as antacids or vitamin with mineral supplements are likely to interfere with the gastrointestinal absorption of oral bisphosphonates. For example, the bioavailability of tiludronate has been shown to decrease 80% during simultaneous administration with calcium, and 60% when aluminum- or magnesium-containing antacids were administered one hour before tiludronate.

MANAGEMENT: Antacids or other oral medications containing aluminum, calcium, magnesium and other polyvalent cations should be administered at least 30 minutes after the bisphosphonate dose.