“…Most studies utilised either fixed tramadol doses of 50 mg ( Al-Haideri, 2013 , De Pedro-Muñoz and Mena-Álvarez, 2017 , Ege et al, 2020 , Isiordia-Espinoza et al, 2012 , Isiordia-Espinoza et al, 2011 , Jendi and Talathi, 2019 , Pozos et al, 2006 , Rodríguez-Wong et al, 2016 ) or 100 mg ( Ceccheti et al, 2014 , Khan et al, 2016 ), a fixed maximum doses of 50 mg ( Jendi et al, 2019 ) or utilised a 1 mg/kg dose ( Aksoy and Ege, 2020a , Aksoy and Ege, 2020b , Gönül et al, 2015 , Iqbal and Shetty, 2019 ).…”