Dronedarone (DND) is a widely used antiarrhythmic drug, and accurate determination of its concentration is crucial for therapeutic monitoring and pharmacokinetic studies. In this work, we report the first fluorometric method for the detection of dronedarone, based on the quenching effect of DND on the red emission of carbon dots (RCDs). The detection mechanism relies on electrostatic interactions between the positively charged DND molecules and negatively charged RCDs in an acidic medium, which induces aggregation of the RCDs and results in significant fluorescence quenching. This quenching enables highly sensitive quantification of DND, achieving a detection limit of 2.31  ng/mL and a wide linear range of 5–200  ng/mL with excellent linearity (R² = 0.9985). The mechanism of detection and thorough characterization of the RCDs were comprehensively investigated. The proposed method also demonstrated outstanding selectivity when applied to both spiked and real rat plasma samples, supporting its potential use in pharmacokinetic evaluations of dronedarone.