DOI: 10.4103/sja.sja_444_26 ISSN: 1658-354X
Effect of COMT gene polymorphism on post-thoracotomy pain and analgesic requirements in patients receiving multimodal pre-emptive analgesia with pregabalin versus naproxen: A randomized clinical trial
Prajjal Das, Rajni Gupta, Vaishali Singh ABSTRACT
Objective:
To evaluate the association between catechol-O-methyltransferase
(COMT)
gene polymorphism and postoperative pain intensity and rescue analgesic requirements in thoracotomy patients receiving pre-emptive pregabalin versus naproxen.
Methods:
In this prospective randomized trial, 40 ASA I–II adults undergoing elective thoracotomy were randomized to pre-emptive oral pregabalin (2.5 mg/kg,
n
= 20) or naproxen (7 mg/kg,
n
= 20). All received standardized thoracic epidural and general anesthesia.
COMT
rs4633 genotypes were determined by polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP). Postoperative numerical rating scale (NRS) pain scores and 24-hour rescue analgesia requirements were recorded.
Results:
The distribution of
COMT
genotypes was similar between groups (
P
= 0.74). Mean NRS scores were lower in Group I compared to Group II at 2 hours (3.6 ± 1.1 vs 4.0 ± 1.2), 6 hours (3.1 ± 1.0 vs 3.5 ± 1.1), 12 hours (2.7 ± 0.9 vs 3.0 ± 1.0), and 24 hours (2.5 ± 0.9 vs 2.8 ± 1.0), with no statistically significant difference (
P
> 0.05). At 24 hours, CT genotype patients showed higher pain scores than CC and TT genotypes in both groups (Group I: 2.9 ± 1.0; Group II: 3.1 ± 1.1). Rescue analgesia was required in 30% of Group I and 45% of Group II patients. Time to first rescue analgesia was longer in Group I (8.6 ± 3.2 h vs 7.4 ± 3.1 h), with fewer rescue doses [median 0 (IQR 0–1) vs 1 (IQR 0–2)].
Conclusion:
Despite non-significant results, CT genotype showed higher pain and analgesic needs, while pregabalin demonstrated a clinically favorable trend over naproxen.