Forest plot illustrating the probability of interaction magnitude between theacrine and caffeine using 90% confidence intervals about the geometric mean ratio of the observed pharmacokinetic parameters following a single theacrine dose (●–25mg, ■–125 mg) alone or in combination with caffeine (150 mg). Abbreviations: MRT0→∞, mean residence time zero to infinity; CL/F, oral clearance; Vz/F, oral volume of distribution; AUC0→∞, area under the curve from zero to time infinity (dose normalized); Cmax, maximum plasma concentration (dose normalized); Tmax, time to reach maximum plasma concentration.