Antidepressant treatments, including selective serotonin reuptake inhibitors, are associated in older adults with an increased risk of adverse effects compared to younger adults. This is partly explained by multiple drug use causing drug–drug interactions. In the present report, we describe a case of serotonin syndrome in an 88-year-old woman receiving a low dose of escitalopram. The onset of this episode could have been induced by a drug–drug interaction with an acute treatment by miconazole gingival adhesive tablets. The lack of pharmacokinetic data in the elderly population should prompt us to be especially cautious about prescription of this new formulation of miconazole in association with drugs metabolized by cytochromes P450 isoenzymes.