Regional block and mexiletine: The effect on pain after cancer breast surgery

Background and Objectives: Breast surgery for cancer is associated with chr onic pain and sensory abnormalities. The present study investigates the eff ect of regional block, oral mexiletine, and the combination of both, on acu te and chronic pain associated with cancer breast surgery. Methods: One hundred patients scheduled for cancer breast surgery received either regional block with 18 mt of 1% ropivacaine intraoperatively and ora l mexiletine for the first 6 postoperative days (R + M group), or regional block and placebo, (R + FL), or normal saline instead of ropivacaine and me xiletine (PL + M), or normal saline acid placebo (PL + FL). Postoperative a nalgesic requirements were recorded daily. Pain was assessed 0, 3, 6, 9, an d 24 hours in the postanesthesia care unit (PACU) and on the second to sixt h day postoperatively, at rest. and after movement using the visual analog scale (VAS). Three months after surgery, patients were interviewed for the presence and intensity ol pain, abnormal sensations, and analgesic requirem ents. Results: Regional block reduced the number of intramuscular (IM) injections required the first 24 hours (P = .05), the R + PL group requiring less inj ections versus the PL + M group (P = .037). Lonarid tablet (paracetamol and codeine) consumption from the second to the fifth postoperative day differ ed among the 4 groups (P = .0304). the R + M group requiring fewer tablets than the PL + PL group (P = .009). Three hours postoperatively, the R + PL group had less pain at rest when compared with all other groups (P < .05 fo r all comparisons). On the second postoperative day, VAS at rest and alter movement was less in the R + M versus the R + PL group (P <less than> .01 a nd P < .05, respectively). Three months after surgery. the 4 groups were si milar with regard to incidence or intensity of pain or analgesic requiremen ts. The R + PL group had a lower incidence (77%) of reduced or absent sensa tion (P = .016). Conclusions: Regional block reduced the analgesic requirements in the early postoperative period, while mexiletine combined with regional block reduce d the total analgesic requirements during the next 5 postoperative days. Al though chronic pain was not affected by these treatments late-abnormal sens ation may be diminished by combination of these treatments.