Efficacy and safety of ketamine and esketamine for preventing opioid-induced cough: a systematic review and meta-analysis of randomized controlled trials. - Hung, Kuo-Chuan; Yu, Ting-Sian; Hsu, Chih-Wei; Liu, Wei-Cheng; Wu, Jheng-Yan; Liao, Shu-Wei; Lin, Chien-Ming; Chen, I.-Wen (Systematic Reviews, 2025)