We identified the first Spt5-Pol II inhibitors (SPIs). SPIs faithfully reproduced Spt5 knockdown effects on proximal-promoter-pausing, NF-κB activation and the expanded-repeat huntingtin gene in neuronal cells. Using SPIs we identified Spt5 target genes that responded with profoundly diverse kinetics and a novel regulatory element of proximal-promoter-pausing. To validate that the effects of SPIs are at the transcriptional level, cellular RNA was metabolically labeled with 4-thio-uridine (4sU) for 2 hours in the presence of DMSO or SPI-21 in the presence or absence of TNFα. Newly synthesized labeled RNA was then purified and subjected to RNA-seq. Overall design: Cellular RNA was metabolically labeled with 4-thio-uridine (4sU) for 2 hours in the presence of DMSO or SPI-21, in the presence or absence of TNFα.