The Peripheral Effect of Fentanyl on Postoperative Pain

A comparison of pudendal block vs dorsal penile nerve block for circumcision in children: a randomised controlled trial

“…The reason for the prolonged pain relief may be due to the addition of clonidine and fentanyl to the local anaesthetic solution. Fentanyl acts via a peripheral mechanism prolonging the duration of anaesthesia and resulting in an improvement of postoperative analgesia [24]. Clonidine has shown to prolong the duration of sensory blockade [25].…”

Peripherally applied opioids for postoperative pain: evidence of an analgesic effect? A systematic review and meta‐analysis

“…Data from 26 RCTs, including 42 comparisons, 1531 patients, and 13 different surgical interventions were analyzed . The range of numbers of patients included in the studies was 20–90.…”

“…For the meta‐analysis, 16 studies (21 comparisons) reported sufficient data on VAS scores, and data were extracted from graphs in nine studies. For the outcome time to first analgesic, five studies (10 comparisons) reported sufficient data.…”

“…Three trials examined elective inguinal hernia repair, including seven comparisons of local infiltration of morphine or fentanyl with similar dose of systemic opioid or placebo administered at the end of surgery. Exclusion criteria in all trials were regular consumption of analgesics .…”

Addition of clonidine and fentanyl: comparison between three different regional anesthetic techniques in circumcision

“…This preemptive effect could have resulted from decreasing the peripheral nociceptive stimulus that decreased the expansion of peripheral hypersensitivity and hyperalgesia. This effect could also be the result of suppression of central nervous system excitability by opioids before the nociceptive input was received and acute pain behavior might be diminished or abolished by local anesthesia (24).…”