In phase 1 clinical trial CI-966 was administered orally. Doses 1-10 mg were well tolerated. A volunteer who received 25 mg of CI-966 developed transient short- and long-term memory deficits. Both volunteers following administration of 50 mg drug doses presented with a constellation of physical and mental disturbances.

The ability of CI-966 to block GABA transport was measured using human cells, stably transfected with GAT-1 transporter. Cells were grown in 25 well plates, washed with Hepes-buffered saline and allowed to equilibrate at 37°C for 10 min. The medium was removed and the drug was added. Transport was initiated by adding 50 uL of a concentrated [3H]GABA solution at a final concentration of 50 nM. Plates were incubated for 10 min, then washed, solubilized, and radioactivity was determined by scintillation counting. CI-966 inhibited [3H]GABA transport with IC50 of 0.26 uM.