Fig. 1. Time–effect curve of intraperitoneal gabapentin (GP) 300 mg/kg and ibuprofen (IBU) 30 mg/kg for flinching (  A ), mean arterial blood pressure (MABP)(  B ), and heart rate (HR)(  C ) on the formalin test. GP and IBU were administered at T =−30 min and formalin (F) was injected subcutaneously at T = 0 min. Data are presented as number of flinches or percentage change from baseline MABP and HR. Each line represented the means ± SEM of 5–7 rats. Statistical analysis for phase 1 and phase 2 dose effects is presented in  figure 2 .