Ture, H., Sayin, M., Karlikaya, G., Bingol, C.A., Aykac, B., & Ture, U. (2009). The analgesic effect of gabapentin as a prophylactic anticonvulsant drug on postcraniotomy pain: A prospective randomized study. Anesthesia and Analgesia, 109(5),1625–1631.

To evaluate the effectiveness of gabapentin in treating acute postoperative pain in patients who have undergone craniotomy

For anticonvulsant prophylaxis, patients were randomized to one of two groups. One group received 1200 mg oral gabapentin daily (400 mg three times/day). The other received 300 mg oral gabapentin daily (100 mg three times/day). Patients took medications for seven days before surgery, as part of the surgical regimen, and postoperatively. All patients received postoperative morphine via patient controlled analgesia (PCA); the dose was titrated up to 0.1 mg/kg IV according to the pain rating on a visual analog scale (VAS). Postoperative follow-up included noting the VAS and Ramsay sedation scores, morphine consumption, and seizure activity or other adverse effects at 0, 15, and 30 minutes and at 1, 2, 4, 6, 12, 24, and 48 hours.

• The sample was composed of 75 patients.
• Mean patient age was 47 years.
• Of all patients, 52% were female and 48% were male.
• All patients had meningioma, glioma, or brain metastases and were undergoing elective supratentorial craniotomy for tumor resection. All patients had tumors with a diameter no larger than 30 mm and a rating of greater than or equal to 15 on the Glasgow coma scale.
• Excluded from the sample were patients taking tricyclic antidepressants, selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, or neuroleptic or antiepileptic drugs.

• Single site
• Inpatient
• Turkey

Randomized parallel-group trial

• Visual analog scale, to measure pain
• Ramsay sedation scale
• Glasgow coma scale

• During the first postoperative hour and at all time points, postoperative VAS scores were significantly higher (p < 0.0001) for those on phenytoin than for those on gabapentin.
• Compared to patients on gabapentin, patients on phenytoin consumed significantly more morphine (p = 0.01), totally and cumulatively.
• During the first two hours after surgery, patients on gabapentin had significantly higher sedation scores (p < 0.05) than did patients on phenytoin.
• Two patients were removed from the study prior to surgery because of apparent side effects of gabapentin. Side effects included severe fatigue and severe dizziness.
• Patients on gabapentin required less perioperative anesthesia than did patients on phenytoin.
• Individuals on gabapentin had a longer time to tracheal extubation (16.6 minutes, SD = 22 minutes) compared to those on phenytoin (4.5 minutes, SD = 2 minutes) (p < 0.001).

Use of gabapentin as a prophylactic anticonvulsant was associated with lower postoperative opioid consumption and lower pain severity. Gabapentin was associated with higher sedation in the immediate postoperative period and a longer time to extubation.

• The study had a small sample size, with fewer than 100 patients.
• The study had a risk of bias due to no blinding.
• The specified use of gabapentin was in a very specific patient population. Findings may not be applicable to other groups of patients.

Gabapentin had significant analgesic effects in patients who had undergone craniotomy, but pain relief was associated with increased sedation and longer time to extubation. In patients undergoing neurosurgery, determining causes of increased sedation or delayed extubation can be difficult and critical. Sedation and delayed extubation can contribute to difficulties in clinical care. Future research should investigate the timing and dosage of gabapentin, with the goal of taking advantage of the drug's positive effects while minimizing negative side effects.