Essential tremor treatment guidelines updated

Propranolol and primidone remain the most successful and most frequently used drugs to treat essential tremor, while levetiracetam, 3,4-diaminopyridine, and flunarizine should not be used, according to updated guidelines by the American Academy of Neurology.

Propranolol is the only FDA-approved medication for the condition, but 30% to 50% of patients with essential tremor (ET) will not respond to it or primidone, the authors noted. To assess other treatments, an expert panel conducted a search of the peer-reviewed literature between 2004 and 2010, selecting 252 controlled trials, observational studies, cohort studies, open-label trials or case series.

The guidelines and summary tables update the previous set released in 2005 on the medical and surgical management of essential tremor. They were published online Oct. 19 by Neurology.

Changes to conclusions and recommendations from the previous guideline include the following:

• Levetiracetam and 3,4-diaminopyridine probably do not reduce limb tremor in ET and should not be considered;
• Flunarizine possibly has no effect in treating limb tremor and may not be considered; and
• There is insufficient evidence to support or refute the use of pregabalin, zonisamide or clozapine as treatment for essential tremor.

Findings unchanged from the previous guideline include:

• Propranolol and primidone are established as effective;
• Alprazolam, atenolol, gabapentin (monotherapy), sotalol and topiramate are probably effective;
• Nadolol, nimodipine, clonazepam, botulinum toxin A, deep brain stimulation and thalamotomy are possibly effective; and
• Gamma knife thalamotomy has insufficient evidence to support or refute its use.

Recent evidence suggests that essential tremor is likely a syndrome or family of diseases, “which adds a layer of complexity to matters,” the authors wrote. “Furthermore, the sequence of molecular events that underlie these degenerative changes has yet to be elucidated, and until such a time, it will be difficult to design specific targets for pharmacotherapeutic intervention.”