A single preoperative dose of diclofenac reduces the intensity of acute postcraniotomy headache and decreases analgesic requirements over five postoperative days in adults: A single center, randomized, blinded trial.

Objective: Postcraniotomy headache causes considerable pain and can be difficult to treat. We therefore tested the hypothesis that a single 100-mg preoperative dose of diclofenac reduces the intensity of postcraniotomy headache, and reduces analgesic requirements.

Methods: 200 patients having elective craniotomies were randomly assigned to diclofenac (n = 100) or control (n = 100). Pain severity was assessed by an independent observer using a 10-cm-long visual analog scale the evening of surgery, and on the 1st and 5th postoperative days. Analgesics given during the first five postoperative days were converted to intramuscular morphine equivalents. Results were compared using Mann-Whitney-tests; P < 0.05 was considered statistically significant.

Results: Baseline and surgical characteristics were comparable in the diclofenac and control groups. Visual analog pain scores were slightly, but significantly lower with diclofenac at all times (means and 95% confidence intervals): the evening of surgery, 2.47 (1.8-3.1) vs. 4. 37 (5.0-3.7), (P < 0.001); first postoperative day, 3.98 (3.4-4.6) vs. 5.6 (4.9-6.2) cm (P < 0.001) and 5th postoperative day: 2.8 (2.2-3.4) vs. 4.0 ± (3.3-4.7) cm (P = 0.013). Diclofenac reduced systemic analgesic requirements over the initial five postoperative days (mean and 95% CI): 3.3 (2.6-3.9) vs. 4.3 (3.5-5.1) mg morphine equivalents (P < 0.05).

Conclusions: Preoperative diclofenac administration reduces postcraniotomy headache and postoperative analgesic requirements - a benefit that persisted throughout five postoperative days.