Interaction between Cefdinir and Iron
Moderate Absorption

ID DDInter315 and DDInter975
Interaction 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.
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.
References
Alternative for Cefdinir J01D
More
Alternative for Iron B03A

A11A

Potential Metabolism Interactions

Substrate-Substrate Interaction:If more than one drug is metabolized by the same CYP, it is possible that its metabolism is inhibited because of the competition between the drugs. That means, it can be useful to lower the dosage of the drugs in the drug-cocktail because they remain longer in the organism than in monotherapy.
Inhibitor-Inhibitor Interaction:Combining two or more inhibitors of one CYP, should be compensated by lowering the dosage of these drugs because the metabolism is reduced and the drugs remain longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.
Inhibitor-Substrate Interaction:Combining drugs that have inhibitory effect and are substrates of one particular CYP, should be compensated by lowering the dosage. They rest longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.