BMJ Group Medical Reference
Oxcarbazepine is often used if carbamazepine doesn't work, or if it causes too many side effects.
It's a drug that's usually used for epilepsy. It can also be used for trigeminal neuralgia. You take it as a tablet or a liquid. The brand name is Trileptal.
There is not much good-quality research into this drug. One long-term study lasting 15 years suggests it does work for many patients.  But there are problems with the study that mean it is not completely reliable. A few trials suggest that oxcarbazepine might work just as well as carbamazepine. 
Oxcarbazepine can cause side effects, including stomach upsets and drowsiness. 
There is a very small risk that taking oxcarbazepine might make you more likely to think about suicide or harming yourself.  If you are worried about any thoughts or feelings you have, see your doctor straight away.
For references related to Trigeminal neuralgia click here