Omnicef Omni-Pac and Multivitamins with minerals

Cefdinir and multivitamin with minerals should not be taken orally at the same time. Products that contain iron may interfere with the absorption of cefdinir and reduce its effectiveness. You should take cefdinir either 2 hours before or 2 hours after the multivitamin with minerals dose. Contact your doctor if you have reddish stools (which may indicate occurrence of the interaction) or your infection worsens. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

ADJUST DOSING INTERVAL: The oral bioavailability of cefdinir may be significantly decreased by concomitant administration of iron preparations. The proposed mechanism is chelation of cefdinir by the iron cation, forming a complex that is poorly absorbed from the gastrointestinal tract. According to the product labeling, coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron (as ferrous sulfate) or vitamins supplemented with 10 mg of elemental iron resulted in a reduction of cefdinir absorption by 80% and 31%, respectively. In a study of six healthy volunteers, simultaneous administration of cefdinir (200 mg single oral dose) with a sustained-release formulation of ferrous sulfate (1050 mg, equivalent to 210 mg elemental iron) led to greater than 90% decreases in mean cefdinir peak plasma concentration (Cmax) and systemic exposure (AUC) compared to administration of cefdinir alone. Even when the iron preparation was administered 3 hours after cefdinir, cefdinir Cmax was still reduced by 25% and AUC by 36%.

MANAGEMENT: To minimize potential interaction with iron, the product labeling recommends that cefdinir be taken at least 2 hours before or 2 hours after administration of iron-containing products. However, this separation time may not be sufficient to prevent the interaction when sustained-release iron products are used, especially in higher dosages. Patients should be advised that reddish stools may occur due to formation of a nonabsorbable complex between cefdinir or its breakdown products and iron in the gastrointestinal tract.