Reply to Kunoe (2020) and Ghosh & Singh (2020) regarding Nunes et al. (2020): Opioid use and dropout from extended-release naltrexone in a controlled trial: implications for mechanism. - Nunes EV; Bisaga A; Krupitsky E; Nangia N; Silverman BL; Akerman SC; Sullivan MA (Addiction (Abingdon, England), 2020)