<p>This study sought to synthesize gold nanoparticles using the ethanolic extract of <i>Monteverdia ilicifolia</i> leaves via ultrasonic-assisted reduction. Techniques such as ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering, and zeta potential were used in their characterization. Field emission scanning electron microscopy and transmission electron microscopy were employed to determine the size and surface morphology of gold nanoparticles synthesized with ethanolic extract of <i>Monteverdia ilicifolia</i> (AuNPs-MI). The modification of carbon-ceramic electrodes (CCE) using AuNPs-MI significantly enhanced their electrochemical properties and electroanalytical performance for the detection of desvenlafaxine succinate, a prominent antidepressant agent. In order to characterize the modified electrodes, cyclic voltammetry and electrochemical impedance spectroscopy techniques were used. Differential pulse voltammetry was employed for the determination of desvenlafaxine succinate, with a limit of detection of 31.2&#xa0;μmol L^–1. Quantification of real drug samples further demonstrated the superior performance of the AuNPs-MI-modified CCE, highlighting both the strong electroanalytical potential of the developed method and the viability of <i>Monteverdia ilicifolia</i> leaves as a green source for synthesizing nanomaterials that enhance electrochemical sensor performance.</p> Graphical abstract <p></p>