TRIGEMINAL NEURALGIA - A GUIDE TO DRUG CHOICE

Trigeminal neuralgia, also known as tic douloureux, is an idiopathic c ondition of severe, unilateral, paroxysmal facial pain. The abrupt nat ure 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 s odium valproate are also effective. Transient relief is sometimes poss ible with local anaesthetics. Limited data suggest that topical capsai cin, and tizanidine, lamotrigine, oxcarbazepine, pyridostigmine and en alapril have helped some patients. While effective, other drugs are li mited by their adverse effects; for example, clonazepam is too sedatin g, pimozide induces extrapyramidal adverse effects, and tocainide and felbamate can cause aplastic anaemia. Phenobarbital (phenobarbitone), opioids, mexiletine, tricyclic antidepressants, corticosteroids, nonst eroidal anti-inflammatory drugs and sympatholytics are ineffective. Th e antineuralgic effect of any drug may eventually wear off. If this oc curs, combination therapy can restore pain relief, as can the reintrod uction of a previously effective drug following a drug-free interval. Similar pharmacological strategies potentially apply to other paroxysm al pain syndromes such as vagoglossopharyngeal neuralgia. Clinical ove rlap with multiple sclerosis or cluster headache suggests additional d rugs that may be useful in specific patients. Effective neurosurgical procedures exist for patients with trigeminal neuralgia that is refrac tory to medications.