Background and Aims Proctological surgery is associated with high-score postoperative pain (VAS>5) [1].

Pudendal block reduces pain and allows a faster return to normal activity [2].

Clonidine has been suggested to improve the quality and duration of peripheral blocks [3 4].

This study investigates whether adding clonidine to levobupivacaine in proctological surgery reduces postoperative consumption of analgesics.

Methods After local ethics committee approval and signed informed consent, adults ASA I/II, scheduled for proctologic surgery under general anesthesia, were enrolled in a prospective, randomized, double-blind, single-centre, pilot study [NCT04530903].

Group. 1 received an ultrasound-pudendal block using 75μg of clonidine per side; group.2 0.5 ml of NaCl 0.9% per side; both groups received 10 ml of levobupivacaine 0,25%.

Primary outcome: total consumption of tramadol in PACU. Secondary outcomes: time between block and first analgesic demand; tramadol request within 24h; postoperative pain; satisfaction.

Continuous data were compared via T-test or Wilcoxon signed-rank test; means±st.deviation or medians are reported. For count data, Pearson Chi-Squared test was performed to compare proportions. P<0.05 was considered significant.

Results Demographics and surgical data were comparable between groups. The groups were not statistically different for the primary outcome (group.1:100 mg; group.2:450 mg; P=0.1677).

55.6% of group.2 requested tramadol in PACU (P=0.09677) compared to 12.5% of group.1.

Within 24h, group.1 required more Tramadol (P=0.05).

VAS longitudinal analysis showed a group-time effect with significantly higher pain within 24h in group.1 (P=0.0477).

Satisfaction was not statically different between groups.

Conclusions Adding clonidine to levobupivacaine in pudendal block did not improve postoperative analgesia.

A large-scale study is needed to further support these results.