Intravenous Fosphenytoin Therapy as Acute Rescue Treatment for Glossopharyngeal Neuralgia Crisis in Patients Awaiting Neurosurgical Procedures: A Case Series

Abstract

Introduction: Few treatments exist for acute attacks of glossopharyngeal neuralgia (GPN). We investigated the efficacy of intravenous fosphenytoin therapy (IFT) during GPN crisis. Case Presentation:We evaluated records of 4 consecutive patients with GPN awaiting microvascular decompression (MVD) who received IFT (total, 750 mg). Pain severity was evaluated using a Numerical Rating Scale (NRS). The score was 10 (maximum pain) before treatment. Case 1 (a 52-year-old woman, left GPN): for 12 hours after IFT, pain was eliminated (NRS 0/10); however, severe pain recurred 2 days later. She received MVD 9 days after IFT. Case 2 (a 72-year-old woman, right GPN): pain score reduced to 0/10 immediately after IFT and remained so for 2 days. Severe pain recurred, and she underwent MVD 4 days after IFT. Case 3 (a 69-year-old woman, right GPN): pain was reduced (NRS, 5/10) immediately after IFT and nearly eliminated (1/10) 1 hour later. After 6 hours, severe pain recurred; she received a second IFT 3 days later, and pain score dropped to 1/10. She was pain-free for 24 hours but intermediate pain recurred in 2 days. Microvascular decompression was performed 9 days after the second IFT. Case 4 (a 32-year-old woman, right GPN): Pain score reduced to 0/10 immediately after IFT and remained so for 4 days. She underwent MVD 4 days after IFT. No evidence of recurrence was found throughout the 24-, 22-, 20-, and 5-month follow-ups.Conclusions: These results provide new insights into the innovative therapeutic option of intravenous fosphenytoin and contribute to advancements in treating acute GPN crisis.

Phenytoin Decreases Pain-like Behaviors and Improves Opioid Analgesia in a Rat Model of Neuropathic Pain

“…After implementation in clinical practice, PHT has been effectively used as a co-analgesic in the treatment of several neuropathic pain syndromes, including trigeminal neuralgia [ 6 ], glossopharyngeal neuralgia [ 7 ], cancer-related pain [ 8 , 9 ], diabetic neuropathy [ 10 ], central pain [ 11 , 12 ], complex regional pain syndrome [ 13 ], Fabry disease [ 14 ] and peripheral neuropathic pain [ 15 ]. Currently, in pain medicine, systemic PHT is recommended and utilized in patients with trigeminal neuralgia as monotherapy or add-on therapy, particularly in patients with trigeminal neuralgia crisis [ 16 , 17 ] and in patients with other severe NP syndromes when immediate and effective control of pain is necessary [ 15 , 18 ]. Although its usage in clinical practice is diminished due to adverse effects, PHT is enumerated on the World Health Organizations List of Essential Medicines; it is cost-effective and easily available in several formulations (per os, parenteral) for out- and inpatient settings, which makes the drug a viable clinical option as monotherapy or in combination with analgesics, e.g., opioids, particularly in patients with acute, severe and refractory NP [ 19 ].…”