Purpose: While several studies reported the influence of co-medications on immune checkpoint therapy and chemotherapy, it remains poorly studied with targeted therapy. Targeted therapies inhibiting BRAF and MEK had significantly improved management of advanced melanoma with BRAFV600 mutation over the last decade, we aimed to investigate the possible influence of co-mediations on the efficacy and toxicity of these targeted therapies (TT). Methods: We conducted an observational study identifying patients with advanced melanoma treated with BRAF/MEK inhibitors between 2013 and 2020 in the Bordeaux University Hospital. Co-medications given within 1 month before until 3 months after the initiation of targeted therapy were recorded and classified by their mechanism or by their metabolism. Survival data were analyzed with univariable and multivariable cox regression and the combined effect of multiple factors was evaluated using a factor analysis of mixed data (FAMD). The impact of co-medications on toxicity related to TT was also assessed. Results: A total of 192 patients were included. Although several co-medications were associated with significantly shorter overall survival (OS) and/or progression-free survival (PFS), PPIs was the only co-medication with a significant impact in multivariable analysis considering all co-medications and specific prognostic factors. Co-medications did not influence the risk, type, or timing of TT-related toxicity. Additional FAMD revealed the impact of each factor on the oncological outcomes. In a subgroup of patients, residual plasma TT concentration was available and did not differ between PPIs users and non-users. Conclusion: Co-medications, especially PPIs, must be carefully assessed at the time of TT initiation.Read less <