Standardized (to bl2/3) MEP amplitudes on the y‐axis plotted against the time points after atDCS under PLC or FLU medication (2.5, 5 or 10 mg). In the PLC condition, anodal tDCS leads to enhanced MEP amplitudes for 30 min post‐stimulation. The administration of 5 and 10 mg of FLU abolished the tDCS‐induced MEP enhancements and partially turned excitability enhancement into inhibition. Intake of 2.5 mg of FLU weakened the excitability changes after anodal tDCS. Excitability elevations lasted from 20 min to 30 min. Filled symbols indicate statistically significant deviations of post‐stimulation MEPs from the respective baseline values. *Significant differences between the PLC and 5 mg of FLU conditions. ×Significant differences between the PLC and 10 mg of FLU conditions (Fisher's least significant difference, P < 0.05). Vertical bars indicate the 95% confidence interval. nm, next morning; ne, next evening.