Abstract
Background: Effective post-operative pain (POP) management begins in the pre-operative period as analgesics administered before surgical incision prevent central sensitization to pain. Fentanyl is a potent synthetic opioid, a most commonly used pre-anesthetic medication. Clonidine is an alpha-2 adrenoceptor agonist, used as a pre-anesthetic medication due to its nonopiate antinociceptive property that provides analgesia in the post-operative period.

Aims and Objectives: The aims of the study were to study the effect of intravenous clonidine as an add-on to intravenous fentanyl premedication on POP in patients undergoing spine surgeries.

Materials and Methods: Forty patients of the American Society of Anesthesiologists status I and II, aged 18–60 years of either sex, undergoing elective spine surgeries were randomized into two groups to receive premedications 30 min before anesthetic induction. Group C received intravenous infusion of clonidine 1.5 mcg/kg over 10 min along with slow intravenous injection of fentanyl 1 mcg/kg. Group F received slow intravenous injection of fentanyl 1 mcg/kg alone. After completion of surgery, patients were shifted to the post-operative recovery ward and on attaining modified Ramsay sedation score of 1, pain was assessed and recorded using numerical rating scale (NRS).

Results: All the study participants completed the study and data were analyzed using per-protocol analysis. Baseline characteristics were comparable between the groups in terms of age, gender, body weight, and total duration of surgery. Sedation levels were found to be comparable between the groups. In Group C, all 20 patients had NRS score of either 4 or <4 and did not require rescue analgesia. In Group F, 8 patients had NRS score of more than 4 and required rescue analgesia. Absolute risk reduction was 40% (P = 0.0014) and number needed to treat was 3. No adverse drug reactions were reported for the entire study period.

Conclusion: Intravenous clonidine 1.5 mcg/kg as an add onto premedication with intravenous fentanyl 1 mcg/kg decreased POP thus reducing requirement of rescue analgesia in patients undergoing spine surgeries.

Key words: Clonidine; Premedication; Fentanyl; Post-operative Pain; Numerical Rating Scale