Trigeminal neuralgia. A guide to drug choice

Trigeminal neuralgia, also known as tic douloureux, is an idiopathic condition of severe, unilateral, paroxysmal facial pain. The abrupt nature of the painful attacks (a temporal profile that is similar to that of seizures) led to the discovery that some anticonvulsant drugs are effective against neuralgia. Carbamazepine is the drug of choice, and treatment requires careful dosage titration. Baclofen, phenytoin and sodium valproate are also effective. Transient relief is sometimes possible with local anaesthetics. Limited data suggest that topical capsaicin, and tizanidine, lamotrigine, oxcarbazepine, pyridostigmine and enalapril have helped some patients. While effective, other drugs are limited by their adverse effects; for example, clonazepam is too sedating, pimozide induces extrapyramidal adverse effects, and tocainide and felbamate can cause aplastic anaemia. Phenobarbital (phenobarbitone), opioids, mexiletine, tricyclic antidepressants, corticosteroids, nonsteroidal anti-inflammatory drugs and sympatholytics are ineffective. The antineuralgic effect of any drug may eventually wear off. If this occurs, combination therapy can restore pain relief, as can the reintroduction of a previously effective drug following a drug-free interval. Similar pharmacological strategies potentially apply to other paroxysmal pain syndromes such as vagoglossopharyngeal neuralgia. Clinical overlap with multiple sclerosis or cluster headache suggests additional drugs that may be useful in specific patients. Effective neurosurgical procedures exist for patients with trigeminal neuralgia that is refractory to medications.