Treatment algorithm
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer
pharmacologic therapy
The mainstay of medical therapy consists of anticonvulsant medications, generally carbamazepine or oxcarbazepine. Carbamazepine is the only anticonvulsant medication with efficacy proven in randomized controlled trials is typically first-line therapy.[20][22][26][27]
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Almost 90% of patients achieve meaningful initial pain control with carbamazepine or oxcarbazepine.[4] However, long-term use may be associated with decreased efficacy.[2] Oxcarbazepine, a derivative of carbamazepine with fewer drug-drug interactions and a lower adverse effect profile, appears equally efficacious. The individual response to both drugs varies significantly; therefore, if one is not effective, the other can be trialled.[2][3]
If carbamazepine and oxcarbazepine are not tolerated or are ineffective, lamotrigine can be used as monotherapy or add-on therapy.[2][3][20] One small randomized cross-over trial (n=14) showed that lamotrigine was efficacious as an add-on therapy for patients with refractory trigeminal neuralgia.[28]
Gabapentin or pregabalin may also be used as monotherapy or add-on therapy.[2][3][4][20] Clinical experience indicates that these agents are less effective than carbamazepine or oxcarbazepine, but are associated with fewer adverse events.[4]
Development of allergic rash with use of carbamazepine or lamotrigine may be a precursor to the development of potentially serious reactions (e.g., Stevens-Johnson syndrome) and should prompt immediate discontinuation.
Patients whose TN is partially or completely refractory to anticonvulsant medications are often tried on other classes of pain medication, such as baclofen, although data supporting their use in TN are scant.[3][20] Baclofen may be helpful for TN in patients with multiple sclerosis who are using the drug for symptoms of spasticity.[2] Based on practitioner preference, it can be given sequentially as monotherapy or in combination until an effective regimen is established.
Primary options
carbamazepine: 200 mg/day orally initially given in 1-2 divided doses, usual maintenance dose is 400-1200 mg/day given in 2 divided doses
OR
oxcarbazepine: 300 mg/day orally initially, usual maintenance dose is 600-1200 mg/day, maximum 1200 mg/day given in 2 divided doses
Secondary options
gabapentin: 300 mg orally once daily initially, usual maintenance dose is 300-1800 mg/day, maximum 1800 mg/day given in 3 divided doses
OR
pregabalin: 75 mg orally (immediate-release) twice daily for 1 week, followed by 150 mg twice daily for 1 week, then 300 mg twice daily thereafter
OR
lamotrigine: consult specialist for guidance on dose
Tertiary options
baclofen: 10 mg orally three times daily initially, usual maintenance dose is 40-80 mg/day, maximum 80 mg/day
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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer
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