Background

Glossopharyngeal neuralgia (GN) is a rare pain syndrome (0.2- 1.3% of all types of cranial neuralgias) along the sensory distribution of the glossopharyngeal nerve, characterized by a brief episodic of sharp/stabbing unilateral pain with abrupt onset and cessation [1], triggered by coughing, talking, or swallowing. 10 % of patients might experience excessive vagal effects during an attack, such as bradycardia, hypotension, syncope, seizures, even cardiac arrest [2].

Case Presentation/ Proposed management

We present the case of a 64-year-old male, with a nine-year history of GN, initially diagnosed as trigeminal neuralgia. The patient was reporting short pain episodes of 30 sec in his right ear, jaw, pharynx, and base of tongue, which aggravated across time, which progressed to unprovoked pain episodes over years. Pain exacerbation was followed by chest pain and shortness of breath. Lamotrigine, indomethacin, paracetamol, diazepam, topiramate, iv phenytoin and subcutaneous morphine, gabapentin and carbamazepine failed to provide pain relief. After a successful trial of intravenous lidocaine infusion (4mg/kg), we introduced a pharmacologically similar oral drug, mexiletine, initially at 200mg/day and further gradual titration to 300mg/day in divided doses. The patient described improved sleep quality and 80% reduction of pain episodes after a week. At 16 months, mexiletine was the sole analgesic at a dose of 450mg/day and patient’s ECG was regularly monitored. A single flare up was reported during this period, where mexiletine was titrated to 600mg/day for a week.

Conclusion

Mexiletine is a sodium channel blocker that is effectively used for neuropathic pain in patients that have responded to intravenous lidocaine. Its clinical value has been questioned due to its significant side effects, high rate of discontinuation and possible short-term effectiveness [3]. Honest communication with the patient is the key to establish a long-term pain management plan and offers time to consider further interventional approaches.