Amr, Y.M., & Yousef, A.A. (2010). Evaluation of efficacy of the perioperative administration of venlafaxine or gabapentin on acute and chronic postmastectomy pain. The Clinical Journal of Pain, 26, 381–385.

To investigate the analgesic efficacy of venlafaxine and gabapentin on acute and chronic pain after breast cancer surgery

Patients were randomized prior to surgery to one of three groups. The venlafaxine group received 37.5 mg of extended release venlafaxine once daily and a second placebo capsule at bedtime. The gabapentin group received 300 mg of gabapentin daily and another placebo capsule at bedtime, and the placebo group received placebo capsules daily and at bedtime. Medications were started the evening before surgery and continued for the first 10 postoperative days. Anesthesia was standardized. When patients complained of pain in recovery they were given a titrated dose of morphine until the VAS pain score was 30 or less. For the first 24 hours postoperatively, IV morphine at 20–50 mcg/kg was given to maintain Visual Analog Scale (VAS) at or below 30. For the remaining time to postoperative day 10, all patients were given acetaminophen and codeine every six hours and as necessary. Pain scores were recorded at rest and with movement at four, 12, and 24 hours on the first postoperative day, then daily for 10 days, then six months later.

• N = 150 
• FEMALES: 100%
• KEY DISEASE CHARACTERISTICS: All had breast cancer
• OTHER KEY SAMPLE CHARACTERISTICS: Patients had either radical or partial mastectomies with axillary dissections.

• SITE: Single site  
• SETTING TYPE: Multiple settings  
• LOCATION: Egypt

• PHASE OF CARE: Multiple phases of care

Double-blinded, randomized, placebo-controlled trial

• Visual Analog Scale (VAS) for pain
• Morphine consumption

Compared to the control group, VAS scores from the second to the tenth day postoperatively were significantly lower in the gabapentin group (p < 0.0003). Compared to controls, VAS scores for pain with movement were significantly reduced for those receiving venlafaxine during days 8–10 (p < 0.0002). Total morphine consumption in the first 24 hours was lower in the gabapentin group compared to both other groups (p < 0.0001). Significantly more patients in the control and gabapentin groups were using opioids for pain at six months (p < 0.05). There were differences among groups in the type of pain reported at six months, but there were no consistent or significant differences in overall pain results. Patients who received venlafaxine had lower prevalence of burning and stabbing or pricking pain. There were no differences between groups in terms of side effects.

The perioperative administration of gabapentin was associated with decreased pain during the acute phase after breast cancer surgery, but it did not appear to have an effect on the incidence of chronic pain after six months postoperatively. The administration of perioperative venlafaxine may have had a beneficial effect on chronic postmastectomy pain syndrome.

• Other limitations/explanation: There was no description or analysis of differences by type of surgery, and it could be expected that individuals who had more extensive procedures could have had more acute and chronic pain.

The findings of this study showed that perioperative gabapentin was associated with reduced pain in the acute postoperative period among women with breast cancer. The use of venlafaxine may have some benefit for long-term neuropathic pain postmastectomy, but these findings were not definitive. This adds to a growing body of evidence regarding the efficacy of gabapentin in reducing acute surgical pain and points to the need for additional research regarding interventions and the potential role of venlafaxine for postmastectomy pain syndrome.