What is the diagnosis and treatment for Trigeminal (TN) neuralgia?

From the Guidelines

Trigeminal neuralgia should be treated with carbamazepine (CBZ) as the first-line agent for pain control, with a starting dose of 200 mg at night and gradually increased by 200 mg every 7 days to a final dose of 400–1200 mg, divided in 2–3 doses per day, as it has been shown to provide partial or complete pain relief in 70% of patients 1. The treatment of trigeminal neuralgia typically begins with anticonvulsant medications, and carbamazepine is the most commonly used and recommended medication for this condition.

• The mechanism of action of CBZ is as a sodium channel-blocker, which helps to reduce the frequency and severity of pain episodes.
• The dosage of CBZ can be adjusted based on the patient's response to treatment, and it is essential to monitor for potential side effects such as drowsiness, headache, and dizziness.
• Alternative medications, such as oxcarbazepine, gabapentin, or pregabalin, may be considered for patients who do not respond to CBZ or experience intolerable side effects 1.
• Surgical options, including microvascular decompression, gamma knife radiosurgery, or percutaneous rhizotomy, may be considered for patients who do not respond to medication or experience severe side effects.
• It is essential to note that trigeminal neuralgia can have a significant impact on quality of life, and treatment should be tailored to each patient's individual needs and circumstances.
• The clinical features of trigeminal neuralgia include sudden, severe, and brief episodes of pain in the distribution of one or more branches of the trigeminal nerve, which can be triggered by various factors such as eating, talking, or exposure to cold air 1.

From the FDA Drug Label

Trigeminal Neuralgia(see INDICATIONS AND USAGE) Initial:On the first day, 100 mg twice a day for tablets for a total daily dose of 200 mg This daily dose may be increased by up to 200 mg/day using increments of 100 mg every 12 hours for tablets, only as needed to achieve freedom from pain. Do not exceed 1200 mg daily. Maintenance:Control of pain can be maintained in most patients with 400 to 800 mg daily. However, some patients may be maintained on as little as 200 mg daily, while others may require as much as 1200 mg daily Carbamazepine tablets are indicated in the treatment of the pain associated with true trigeminal neuralgia.

The initial dose of carbamazepine for Trigeminal Neuralgia is 100 mg twice a day, with a total daily dose of 200 mg. The dose can be increased by up to 200 mg/day in increments of 100 mg every 12 hours as needed to achieve freedom from pain, not exceeding 1200 mg daily. The maintenance dose to control pain is typically between 400 to 800 mg daily, but can range from 200 mg daily to 1200 mg daily 2. Carbamazepine is indicated for the treatment of pain associated with true trigeminal neuralgia 2.

From the Research

Definition and Characteristics of Trigeminal Neuralgia

• Trigeminal neuralgia (TN) is a highly disabling disorder characterized by very severe, brief, and electric shock-like recurrent episodes of facial pain 3.
• It is one of the most debilitating presentations of orofacial pain, with a significant impact on the quality of life of affected patients 4, 5.

Diagnosis and Diagnostic Criteria

• New diagnostic criteria subclassify TN based on the presence of trigeminal neurovascular conflict or an underlying neurological disorder, allowing for better characterization of patients and decision-making regarding medical and surgical treatments 3.
• MR imaging, including high-resolution trigeminal sequences, should be performed as part of the diagnostic work-up 3.

Treatment Options

• The first-line treatment for TN remains anticonvulsant medical therapy, with carbamazepine and oxcarbazepine being the drugs of first choice 4, 3, 6, 5, 7.
• Other drugs that can be used either alone or as add-on therapy include lamotrigine, gabapentin, pregabalin, botulinum toxin type A, and baclofen 3, 5.
• Surgical options are available for patients who fail medical therapy, including microvascular decompression, percutaneous methodologies (e.g., glycerol or radiofrequency ablation), and radiosurgery 4, 3, 6.
• Peripheral neurectomies can provide an inexpensive and resource-sparing alternative to pain relief for patients in locations with limited economic and medical resources 4.

Pharmacological Treatment

• The antiepileptic drugs carbamazepine and oxcarbazepine are the first-line pharmacological treatment for TN, with a mechanism of action that modulates voltage-gated sodium channels, leading to a decrease in neuronal activity 5, 7.
• New pharmacological alternatives are being explored, such as the active metabolite of oxcarbazepine, eslicarbazepine, and the new Nav1.7 blocker vixotrigine 5, 7.