In this phase 1, single-center, single-sequence, open-label, 2-intervention, drug-drug interaction study, healthy adults received atogepant 60mg on day 1, quinidine gluconate 324mg twice-daily on day 8, and 648mg twice-daily on days 9–12, with atogepant 60mg coadministered on day 11. Plasma samples were collected on days 1 and 11. Atogepant PK parameters calculated were peak plasma concentration (C_max); time to C_max (t_max); and area under plasma concentration-time curve from time 0 to time t (AUC_0-t) and infinity (AUC_0-∞). PK parameters of atogepant coadministered with quinidine gluconate vs atogepant administered alone were compared using mixed-effects model. Statistical significance was achieved if 90% confidence intervals (CIs) for least squares geometric mean ratios (GMRs) of PK parameter values for atogepant coadministered with quinidine gluconate to atogepant administered alone were within 80%–125%. Safety assessments included clinical laboratory values, vital signs, electrocardiograms, and treatment-emergent adverse events (TEAEs).