Low-dose Fosphenytoin for Aborting Acute Trigeminal Neuralgia Pain: A Case Report.

Introduction: While the typical treatment for trigeminal neuralgia is carbamazepine, the dose must be gradually titrated over time to achieve pain control, which makes the drug a less than ideal candidate for treatment for acute exacerbation of pain due to trigeminal neuralgia in the emergency department (ED) setting. The literature for other effective treatments for acute exacerbations of trigeminal neuralgia is currently lacking. We discuss a case where intravenous (IV) fosphenytoin was used for treatment of acute pain due to trigeminal neuralgia in the ED.

Case Report: This is a case of a 35-year-old male diagnosed with trigeminal neuralgia who presented with acute facial pain. His history and physical exam were consistent with an acute exacerbation of his trigeminal neuralgia. The patient was refractory to multiple doses of standard pain medication in the ED, and the decision was made to attempt IV fosphenytoin to relieve his pain. He was given 250 milligrams of fosphenytoin that was infused via IV over 10 minutes. By the end of the infusion, the patient had reported complete resolution of his pain.

Conclusion: Fosphenytoin is a viable treatment option for pain relief in patients with acute exacerbation of trigeminal neuralgia. It may be a more favorable drug to use in the ED for acute pain given that carbamazepine must be titrated to effect. It is also possible that lower doses of fosphenytoin may provide equally beneficial analgesic effect than what is described in the literature, as pain relief was achieved in our case with approximately 3 milligrams/kilogram of fosphenytoin.