BACKGROUND: Patients with Brugada syndrome (BrS) are recommended to avoid drugs that may increase their risk of arrhythmic events. We examined treatment with such drugs in patients with BrS after their diagnosis. METHODS AND RESULTS: All Danish patients diagnosed with BrS (2006– 2018) with >12 months of follow-up were identified from nationwide registries. Nonrecommended BrS drugs were grouped into drugs to “avoid” or “preferably avoid” according to http://www.brugadadrugs.org. Cox proportional hazards analyses were performed to identify factors associated with any nonrecommended BrS drug use, and logistic regression analyses were performed to examine associated risk of appropriate implantable cardioverter defibrillator therapy, mortality, and a combined end point indicating an arrhythmic event of delayed implantable cardioverter defibrillator implantation, appropriate implantable cardioverter defibrillator therapy, and mortality. During a median follow-up of 6.8 years, 93/270 (34.4%) patients with BrS (70.4% male, median age at diagnosis 46.1 years [interquartile range, 32.6– 57.4]) were treated with ≥1 nonrecommended BrS drugs. No difference in any nonrecommended BrS drug use was identified comparing time before BrS diagnosis (12.6%) with each of the 5 years following BrS diagnosis (P>0.05). Factors associated with any nonrecommended BrS drug use after diagnosis were female sex (hazard ratio [HR]) 1.83 [95% CI, 1.15– 2.90]), psychiatric disease (HR, 3.63 [1.89– 6.99]), and prior use of any nonrecommended BrS drug (HR, 4.76 [2.45– 9.25]). No significant association between any nonrecommended BrS drug use and implantable cardioverter de-fibrillator therapy (n=20/97, odds ratio [OR], 0.7 [0.2– 2.4]), mortality (n=10/270, OR, 3.4 [0.7–19.6]), or the combined end point (n=38/270, OR, 1.7 [0.8– 3.7]) was identified. CONCLUSIONS: One in 3 patients with BrS were treated with a nonrecommended BrS drug after BrS diagnosis, and a BrS diagnosis did not change prescription patterns. More awareness of nonrecommended drug use among patients with BrS is needed.