“…The rapid onset facilitates the completion of a diagnostic workup with a lower incidence of hemodynamic side effects while allowing for rapid clinical reevaluation (Chudnofsky, Wright, Dronen, Borron, & Wright, 1989;Peng & Sandler, 1999). Hence, nebulized fentanyl has been one of the most commonly evaluated opioids for the treatment of acute pain in the ED including for the treatment of abdominal pain, acute limb pain, and renal colic (Bartfield, Flint, McErlean, & Broderick, 2003;Deaton, Auten, & Darracq, 2015;Farahmand et al, 2014;Furyk, Grabowski, & Black, 2009;Imamoglu et al, 2017;Maleki Verki, Mozafari, Tirandaz, Motamed, & Khazaeli, 2019;Rezaei, Salimi, Kalantari, & Astaraki, 2021;Thompson & Thompson, 2016). The doses of fentanyl studied via nebulization range from the most commonly used doses via the intravenous (IV) route (1-2 mcg/kg) given via nebulization.…”