What is the recommended treatment for trigeminal neuralgia?

Treatment of Trigeminal Neuralgia

First-Line Pharmacological Treatment

Start with carbamazepine or oxcarbazepine as first-line therapy, with oxcarbazepine preferred when tolerability is a concern due to its superior side effect profile despite equal efficacy. 1, 2

Carbamazepine Dosing

• Initial dose: 100 mg twice daily (200 mg/day total) 3
• Titration: Increase by up to 200 mg/day in increments of 100 mg every 12 hours as needed to achieve pain freedom 3
• Maximum dose: 1200 mg/day 3
• Maintenance: Most patients achieve control with 400-800 mg daily 3
• Expected response: Up to one-third of eventual responders experience relief within 24 hours, over 40% within one week, and more than 75% within three months 1

Key Considerations for First-Line Therapy

• Carbamazepine is FDA-approved specifically for trigeminal neuralgia and remains the gold standard with an NNT of 1.7 3, 4
• Oxcarbazepine is equally effective but better tolerated, making it the preferred first-line option for many patients 1, 2
• Take medication with meals to improve tolerability 3
• Approximately 75% of patients initially achieve complete pain relief with carbamazepine 1

Second-Line Pharmacological Options

When first-line agents fail or cause intolerable side effects, proceed to second-line medications:

• Lamotrigine: Particularly effective when added to carbamazepine (NNT = 2.1) 1, 4
• Baclofen: Demonstrated efficacy with NNT of 1.4 1, 4
• Gabapentin combined with ropivacaine: Shown effective in randomized controlled trials 1, 2
• Pregabalin: Demonstrated efficacy in long-term cohort studies 1, 2

Special Considerations for Elderly Patients

• Gabapentin: Start at 100-200 mg/day, gradually increase to 900-3600 mg/day in 2-3 divided doses 1
• Pregabalin: Start at 25-50 mg/day, gradually increase to 150-600 mg/day in two divided doses 1
• Baclofen: Initial dose 5 mg three times daily, rarely tolerate above 30-40 mg/day in elderly 1
• Nortriptyline: Start 10-25 mg at night, increase every 3-7 days up to 25-100 mg at night 1
• 5% lidocaine patch: Consider for localized pain due to low systemic absorption and excellent tolerability 1
• Lower starting doses and slower titration are essential in elderly patients 1

Surgical Interventions

Consider surgical options when pain intensity increases despite medication optimization or when side effects become intolerable. 1, 2

Microvascular Decompression (MVD)

• Preferred procedure for younger patients with minimal comorbidities and neurovascular compression 1, 2
• Efficacy: 70% chance of being pain-free at 10 years 1, 2
• Complications: 2-4% risk of hearing loss, 0.4% mortality 1, 2
• This is the only non-ablative surgical option 1

Ablative Procedures for Elderly or High-Risk Patients

Consider these options when MVD is not appropriate:

• Radiofrequency thermocoagulation 2, 5
• Glycerol rhizotomy 1, 2
• Balloon compression 1, 2
• Gamma Knife radiosurgery: Delivers minimum 70 Gy to 4 mm target, provides relief within three months in three-quarters of patients initially, but only half maintain relief at three years 1

All ablative procedures result in varying degrees of sensory loss, with anaesthesia dolorosa being the most concerning complication of radiosurgery 1

Treatment Algorithm

1. Initiate carbamazepine or oxcarbazepine at appropriate starting doses 1, 2, 3
2. Titrate to effect over weeks, monitoring for side effects 3
3. If inadequate response at 3 months (15% fail to achieve 50% pain relief): Add second-line agent (lamotrigine, baclofen, gabapentin, or pregabalin) 1, 4
4. If medication optimization fails or side effects intolerable: Obtain early neurosurgical consultation 1, 2
5. Surgical decision: MVD for younger, fit patients; ablative procedures for elderly or those with significant comorbidities 1, 2, 5

Critical Diagnostic Considerations Before Treatment

Rule Out Secondary Causes

• Obtain MRI with contrast in all suspected cases to identify neurovascular compression and exclude multiple sclerosis, tumors, or other structural lesions 2, 6
• Giant cell arteritis: Must be ruled out urgently in patients over 50 with temporal region pain to prevent blindness 1, 2
• Sensory deficits in trigeminal distribution require urgent imaging 6

Distinguish from Mimics

• Trigeminal autonomic cephalgias (SUNCT/SUNA): Present with tearing, eye redness, rhinorrhea, up to 200 attacks daily with no refractory period 1, 2, 6
• Post-herpetic neuralgia: Continuous burning pain at site of previous herpes zoster, not paroxysmal 2, 6
• Glossopharyngeal neuralgia: Deep ear/throat pain triggered by swallowing, may cause syncope 6
• Type 2 trigeminal neuralgia: Prolonged continuous pain between sharp attacks, may have central origin 1, 6

Common Pitfalls and Caveats

• Do not use carbamazepine for trivial aches or pains—it is not a simple analgesic 3
• Absence seizures are not controlled by carbamazepine—this is specific to trigeminal neuralgia and certain seizure types 3
• Attempt dose reduction every 3 months to find minimum effective level or potentially discontinue 3
• Monitor carefully for side effects in elderly patients, particularly drowsiness, dizziness, mental confusion, and dry mouth 1
• Adjust doses in renal impairment for gabapentin and pregabalin 1
• Set realistic expectations: Patients may expect 100% pain relief off all medications for over 5 years after surgery, but this is not guaranteed 1
• Combination therapy may allow lower doses of carbamazepine/oxcarbazepine, reducing adverse effects, but watch for drug-drug interactions 7