Table 3.
Drug options for trigeminal neuralgia
| Drug | Level of evidence | Effect | Adverse effects | Suggested dose | Comment |
|---|---|---|---|---|---|
| Standard treatment (reasonable evidence) | |||||
| Carbamazepine | 1 systematic review of 4 randomised controlled trials (n=160)15 | Number needed to treat for any pain relief 1.9 (95% CI 1.4 to 2.8); 72% of patients had excellent or good response | Drowsiness, ataxia, nausea, constipation; number needed to treat (minor) 3.7 (2.4 to 7.8); number needed to treat (major) not significant | 100 mg twice daily; increase as necessary by 50-100 mg every 3-4 days18; target range 400-1000 mg/day | Dose may need to be adjusted after 3 weeks because of enzyme induction |
| Second line (evidence weak or adverse effects limit use) | |||||
| Baclofen | 1 controlled trialw7 compared baclofen with placebo (n=10) | 7/10 improved with baclofen; 0/10 improved with placebo (P=0.05) | Drowsiness, hypotonia; avoid abrupt withdrawal | 10 mg three times daily; increase as necessary by 10 mg/day; target dose 50-60 mg daily18 | May be useful in patients with multiple sclerosis where its antispasticity effects can be harnessed |
| Gabapentin | 5 uncontrolled studies (n=123)18 | Good to excellent pain relief in 40%, any pain relief in 53% | Drowsiness, ataxia, diarrhoea; number needed to treat (minor) 2.5 (2.0 to 3.2) | 300 mg once daily; increase as necessary by 300 mg every 3 days in divided doses (three times daily); target dose 900-2400 mg daily | Widely used for trigeminal neuralgia although evidence is weak; evidence base in other types of neuropathic pains much stronger14 |
| Lamotrigine | 1 randomised controlled trial with lamotrigine as add on to carbamazepine or phenytoin (n=14)w8 | 10/13 improved on lamotrigine; 8/14 improved on placebo; not statistically significant | Drowsiness, dizzyness, constipation, nausea; in a randomised controlled trial the side effects were no different to placebo17 | 25 mg twice daily; increase by 50 mg weekly; target dose 200-600 mg daily | Probably better tolerated than carbamazepine but needs slow titration; may therefore have a role in the elderly or patients with multiple sclerosis who have less severe disease |
| Oxcarbazepine | 2 uncontrolled studies (n=21)18 | Pain relief in all 21 patients | Dizziness, fatigue, rash, and hyponatraemia | 300 mg twice daily; increase by 600 mg weekly; target dose 600-2400 mg daily | Evidence weak; structurally similar to carbamazepine although probably better tolerated18; used as first line drug in Scandinavia17 |
| Phenytoin | 3 uncontrolled studies (n=30)18 | 77% of patients reported some pain relief | Drowsiness, ataxia, dizziness, gum hypertrophy | 300 mg a day; dose may be altered to achieve therapeutic plasma concentrations | First drug used in the successful management of trigeminal neuralgia; little evidence but rapid dose titration and once daily dosing are advantages |
| Pimozide | 1 randomised controlled trial compared with carbamazepine (n=48)w9 | 100% improved on pimozide v 56% on carbamazepine | Extrapyramidal side effects, cardiac arrhythmia, sudden death18. | 2 mg once daily; increase as necessary by 2 mg weekly; target dose 2-12 mg/day. | An effective drug but use is severely limited by extrapyramidal effects and cardiac toxicity; potential of tardive dyskinesia limits use even more |