Gabapentin-induced changes of plasma cortisol level and immune status in hysterectomized women

Abstract

We have examined the effects of gabapentin (GBP) on stress-related changes of cortisol and catecholamines in patients who underwent hysterectomy because of uterine fibrinoids. Additionally, we have observed the effect of GBP on the immune status in the acute stress response to surgery. Sixty patients scheduled for an abdominal hysterectomy were randomly assigned to the GBP administration 1h before surgery (n=30 pts), or to the placebo group (n=30 pts). Blood samples were collected before and 24h after the surgery. The intensity of pain was assessed by a visual analogue scale (VAS) every 8h at rest. Immunomodulatory effects of GBP were determined by flow cytometry. We followed the total proportion of CD3(+) lymphocytes, CD3(+)CD4(+), CD3(+)CD8(+), CD19(+) B lymphocytes, CD16(+)CD56(+)CD3(-)NK cells and CD16(+)CD56(+)CD3(+) NKT cells before and 24h after hysterectomy. The plasma cortisol and catecholamines concentration was used to estimate the level of the stress response. VAS pain score at rest was significantly lower in the GBP group than in the placebo group (P=0.003). Application of GBP significantly decreased the plasma cortisol level 24h after the operation in comparison to the placebo group (P<0,001). We found significant positive correlation between the VAS pain score and concentration of cortisol in all patients (P=0.025). GBP reduced the concentration of catecholamines (p<0.05). The proportion of CD3(+) (P=0.027) and CD3(+)CD4(+)cells (P=0.006) was significantly lower in the GBP group 24h after operation, while the contribution of CD19(+) (P=0.033) was significantly higher. Preoperative administration of GBP reduced the pain scores at rest in patients at 0, 16 and 24h after abdominal hysterectomy. Additionally, GBP reduced the stress response and changed immune parameters in the reaction to surgery.