A fixed dose was used for each dosage group. Group 1 received 262.5 mg over 48 h, group 2 received a total dose of 525 mg over 48 h and patients in group 3 received a total dose of 105 mg over a period of 6 h. ZK 200775 (fanapanel) was administered as an intravenous loading infusion over 30 min followed by a maintenance infusion over 47.5 h (groups 1 and 2) or 5.5 h (group 3). During the infusion, heart rhythm, body temperature, blood pressure, respiration rate and oxygen saturation were recorded at 30 min intervals for the first 4 h, thereafter at hourly intervals.

The potency of quinoxalinediones in inhibiting the specific binding of 3H-AMPA, 3H-6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), 3H-kainate, 3H-3-(2-carboxypiperazin-4-yl)-propyl-1phosphonate (CPP), 3H-1-[1-(2-thienyl)cyclohexyl]piperidine (TCP), 3H-dihydrochlorokynurenate (DCKA), and 3H-glycine was tested on rat cortical membranes. The receptor binding profile of ZK200775 (fanapanel) showed high affinity to 3H-AMPA (120 nM) and 3H-CNQX (32 nM) binding sites. It was 21-fold less potent at 3H-kainate (2.5 μM) and had weak affinity to the binding sites within the NMDA receptor complex such as 3H-CPP (2.8 μM), 3H-TCP (11 μM), 3H-dichlorokynurenate (2.8 μM), and 3H-glycine (5.15 μM) sites. No affinity to nonglutamate receptor binding sites was detected up to concentrations of 20–100 μM in rat cortical membrane preparations.