To assess the effectiveness of nebulized fentanyl used for analgesia in renal colic.

This research was planned as a randomized, blinded study in which prospectively collected data were analyzed retrospectively to compare nebulized and intravenous (iv) fentanyl therapies. Patients with renal colic with ‘moderate’ or worse pain on a four-point verbal pain score (VPS) or with pain of 20mm or above on a 100-mm visual analogue score (VAS) at time of presentation were randomized into iv fentanyl (n=62) or nebulized fentanyl (n=53) study groups. Decreases in VAS and VPS scores at 15 and 30min compared to baseline, rescue analgesia requirements and side-effects between the groups were compared.

Both iv fentanyl and nebulized fentanyl provided effective analgesia in renal colic patients at the end of 30min. However, iv fentanyl provided more rapid and more effective analgesia than nebulized fentanyl. Patients receiving iv fentanyl had lower rescue analgesia requirements than those receiving nebulized fentanyl (37.1% vs 54.7%), although the difference was not statistically significant (p=0.058). In addition, side-effects were more common in the iv fentanyl group compared to the nebulized fentanyl group (22.1% vs 9.4%), although the difference was also not significant (p=0.058).

Nebulized fentanyl provides effective analgesia in patients with renal colic. However, iv fentanyl exhibits more rapid and more powerful analgesic effects than nebulized fentanyl. Nonetheless, due to its ease of use and few potential risks and side-effects the nebulized form can be used as an alternative in renal colic.