Carbamazepine is the best studied treatment for classic TN and is established as effective. Side effects can be a problem but are generally manageable, particular if low doses are prescribed initially with gradual titration, concluded that carbamazepine is effective for controlling pain in patients with classic TN, oxcarbazepine is probably effective, and baclofen, lamotrigine, and pimozide are possibly effective.

There is limited data and uncertain effectiveness regarding other drugs that have been used for TN, including clonazepam (Klonopin), gabapentin (Neurontin),  phenytoin (Dilantin), tocainide (Tonocard), tizanidine (Zanaflex), and valproate (Depakote).

Carbamazepine (Tegretol) — Four randomized, controlled trials with a total of 147 patients have established the effectiveness of carbamazepine (200 to 2400 mg daily) for TN

A systematic review and practice parameter published in 2008 from the American Academy of Neurology (AAN) and the European Federation of Neurological Societies (EFNS) noted that the treatment response in these trials was robust, with complete or near complete pain control attained in 58 to 100 percent of patients on carbamazepine, compared with 0 to 40 percent of patients on placebo. For the outcome of important pain relief, the number needed to treat was <2. However, carbamazepine was sometimes poorly tolerated, with numbers needed to harm for minor and severe adverse events of 3 and 24 respectively.

Oxcarbazepine (Trileptal) — Oxcarbazepine, an analogue of carbamazepine, was developed to retain the antineuralgic effect of carbamazepine while reducing side effects.
The AAN/EFNS practice parameter identified several randomized controlled trials that compared oxcarbazepine (600 to 1800 mg daily) with carbamazepine in 178 patients with classic TN [26]. In the pooled analysis, both medications were equally effective, with a >50 percent reduction of attacks achieved by 88 percent or more of patients in both treatment groups.

Baclofen (Baclofen) — Limited evidence from a small double-blind crossover trial suggests that baclofen is beneficial for TN. Treatment with baclofen 40 to 80 mg daily resulted in a reduction in paroxysms in seven of 10 patients with typical TN, compared with one of 10 who received placebo

Lamotrigine (Lamictal) — In a small double-blind, placebo-controlled crossover study of patients with TN that was refractory to carbamazepine or phenytoin, adjunct therapy with lamotrigine (400 mg daily) was beneficial for improvement on a composite outcome index. Patients continued taking either carbamazepine or phenytoin for the duration of the trial. Similarly, an open-label study found that lamotrigine was beneficial 11 of 15 patients with TN once the 400 mg dose was reached. However, the clinical utility of lamotrigine for severe pain is limited by the need to titrate the dose over many weeks

Pimozide (Orap) — Pimozide, a dopamine receptor antagonist, was more effective than carbamazepine in a randomized, double-blind crossover trial of 48 patients with refractory TN ]. There were no drop-outs among patients taking pimozide. However, pimozide is seldom used because it has many potentially serious side effects, including sedation, arrhythmias, anticholinergic effects, acute extrapyramidal symptoms and parkinsonism.
 

Other medications — Tizanidine appeared to be more effective than placebo in a small one-week trial, but patients who continued the drug in follow-up developed recurrent attacks of TN within one to three months

Tocainide was as effective as carbamazepine at two weeks in a small cross-over trial.

Small open label studies have suggested benefit with a number of medications used for TN

* phenytoin (Dilantin),
* Fosphenytoin (Cerebyx)
* valproate (Depakote).
* gabapentin (Neurontin),
* Pregabalin (Lyrica)
* clonazepam (Klonopin),
* Topiramate (Topamax)
* Misoprostol (Cytotec), in patients with TN and multiple sclerosis

However, these agents have not been studied in controlled trials, and their effectiveness in TN is not established