CYP2D6 gene polymorphisms and the quality of postoperative analgesia with tramadol after vascular surgery

Abstract

Relevance. The quality of postoperative anesthesia may depend on the individual genetic characteristics of the patient. Thus, the C100T and G1846A polymorphisms in the CYP2D6 gene can change the biotransformation of tramadol and, consequently, its clinical effect.Objective. To evaluate the quality of postoperative pain relief based on tramadol after vascular operations depending on the presence/absence of polymorphisms in CYP2D6, an isoenzyme of cytochrome P450.Materials and methods. We examined 78 patients aged 52 [49–61] years who underwent routine operations on the vertebral arteries. Every 3 h after surgery, pain was assessed using a visual analog scale. Before and after the operation, variability in heart rate was analyzed according to the method described by Baevsky. The presence of polymorphisms C100T and G1846A in CYP2D6 was determined from whole blood samples. The obtained data were analyzed using nonparametric statistics.Results. When assessing the CYP2D6 gene, polymorphisms were identified in 22 (28.2 %) patients: G1846A in 18 (23.1 %) patients and C100T in 4 (5.1 %). Patients were retrospectively divided into 2 groups: group 1 (n=56) included patients without studied polymorphisms of the CYP2D6 gene and group 2 (n=22) — with identified polymorphisms. Pain syndrome according to VAS at rest was more intense in group 2 at 18:00, 21:00, and 09:00 on the first postoperative day, when patients were activated — at 18:00 and 09:00 (p<0.05). The stress index after surgery was also higher in group 2 (p<0.05).Conclusions. The frequency of occurrence of polymorphisms G1846A and C100T of the CYP2D6 gene in vascular patients was 28.2 %. These patients had a more pronounced postoperative pain syndrome and greater activity of the sympathetic nervous system. The determination of these polymorphisms can be used to create an effective personalized plan for postoperative pain relief.