Nucleic acid drug carriers comprise a nucleic acid carrier complexed with a drug, wherein the nucleic acid carrier and the drug are associated non-covalently, and optionally other agents such as spacer, transfection agents, and targeting agents. The nucleic acid drug complex are discovered to have permissive or refractory uptake depending on many factors including cell type, proliferation rate, among others. The refractive uptake of the nucleic acid drug complex are shown to be useful in the nucleic acid targeting of drugs, both in vitro and in vivo. Novel drug compositions are disclosed that effectively reduce the toxicity of drugs while maintaining drug activity and enhancing a drug's therapeutic index.