Q. Are there any new medications coming out to treat tremor related to Tourette's or Parkinson's? What medications would you recommend?

A. There are new approaches to both Tourette's Syndrome (TS) and Parkinson's Disease (PD), but please keep in mind these are very different disorders--and tremor in one may mean something quite different from a similar symptom in the other.

TS is primarily a tic disorder, unlike PD, which is mainly a disorder of slowed movements, tremor, and muscle rigidity. We still don't really know the underlying neurochemical basis of Tourette's syndrome, though the brain chemicals dopamine and serotonin are probably involved. One theory holds that in TS, certain brain receptors for dopamine are overly sensitive; in contrast, in Parkinson's Disease, there is too little dopamine in these brain regions.

Thus, tremor may mean different things in each condition, and must also be distinguished from tremor as a side effect of medications used to treat these conditions. Traditionally, TS has been treated mainly with agents that block dopamine receptors, such as haloperidol or pimozide. These may actually provoke tremor or muscle rigidity, even though they may reduce vocal or motor tics.

Newer alternatives in TS have included atypical antipsychotics, such as risperidone or olanzapine (see Dion et al, J Clin Psychopharmacol 2002 Feb;22(1):31-9), which are less likely to cause or worsen underlying tremor. (In some cases of TS, tremor may actually be a kind of tic equivalent--see Kulisevsky et al, Arch Neurol 1998 Mar;55(3):409-14).

Other agents that act on a different brain chemical (norepinephrine) are also used in TS; e.g., clonidine and guanfacine. Newer treatments for PD actually tend to boost dopamine function. One new agent, pramipexole, appears to be useful in reducing tremor associated with PD, even in patients who have not responded well to more traditional PD treatments, such as L-dopa (Pogarell et al, J Neurol Neurosurg Psychiatry 2002 Jun;72(6):713-20).

There is also interest in using a drug called gabapentin for PD-related tremor, though the data are preliminary (Lopez et al, Rev Neurol 2003 Feb 16-28;36(4):322-6). Recently, a number of non-medication procedures have also been used with some success in PD, such as deep brain stimulation and a surgical procedure known as thalamotomy. For specific recommendations concerning your own care, or that of a loved one, I would advise consulting with a neurologist or neuropsychiatrist.

Other Resources:

• More Questions on Tourette's Syndrome

September 2003

Disclaimer Back to Ask the Expert