Coadministration has not been studied. The primary route of decitabine metabolism is likely by cytidine deaminase. Decitabine is a prodrug and is activated intracellularly through sequential phosphorylation via phosphokinases activities to the active triphosphate. Phosphorylation of emtricitabine occurs via the same enzymes and competition may occur for this activation path. However, the clinical relevance of this interaction is unknown. No interaction is expected with tenofovir-DF.