Fig. 2.

Concentration-effect plots of blood pressure. Each data point represents the mean concentration-effect with the vertical error bar indicating the S.D. of the measured effect and the horizontal error bar representing the S.D. in the cocaine plasma concentration. The solid and broken lines are derived from the simple E_max model equation using the mean (n = 6) values of E0, EC₅₀, and E_max for cocaine alone and cocaine plus ethanol. The virtually superimposable E_max fits indicate that ethanol does not alter the concentration-effect relationship of cocaine.