Few treatments exist for acute attacks of
trigeminal neuralgia. Therefore, this study aimed to investigate the efficacy and safety of an intravenous
fosphenytoin therapy protocol in a
trigeminal neuralgia crisis. We conducted a single-center, retrospective, observational study of the records of 20 patients with
trigeminal neuralgia who received intravenous
fosphenytoin therapy (15 mg/mL in
normal saline at 50 mg/min for 15 min, total 750 mg) during hospitalization between September 2015 and August 2020. Serum
phenytoin concentration was measured 30 min post-infusion.
Pain severity was evaluated using a numerical rating scale and was analyzed for statistical significance. The mean age of the patients was 67.5 years (female, 50.0%). The median numerical rating scale score (interquartile range) of
pain severity was 2.35 (0-10), 0.65 (0-5), 0.15 (0-1), 2.00 (0-8), and 4.30 (0-10) at 15, 30, and 60 min, and 12 and 24 h, respectively (p < .001); the numerical rating scale score was 10 before treatment. Reduction in
pain 24 h following treatment was significant. The mean
phenytoin concentration was 12.8 μg/mL 30 min post-treatment. While mild
dizziness occurred in four patients, all could walk independently within 60 min. The mean age and weight of patients with mild
dizziness were significantly higher and lower, respectively (p < .001), than those of other patients. These results may provide physicians with new insights into the innovative therapeutic option of intravenous
fosphenytoin and contribute to advancements in treating acute
trigeminal neuralgia crisis.