Tardive Dyskinesia Drugs & Classes

It is well established that tardive dyskinesia - which is a movement disorder that causes victims to twitch in an uncontrolled and/or spasmodic manner - is caused by the use of certain anti-psychotic medications, specifically those classified as "first generation" or "typical." First generation anti-psychotics were developed between 1950 and 1970. There are some nineteen different "first generation" antipsychotic medications that continue to be used.

"Second-generation" antipsychotics, which were developed between 1970 and 1990 and "third generation" medications that have come out since the 1990s are also called "atypical." A 2000 study at the University of Cincinnati School of Medicine showed that when it came to the treatment of "acute mania," these second generation "atypical" medications worked as well as those "typical" medications of the first generation. However, use of second generation medications did not necessarily mean that a patient medicated with these drugs would not develop tardive dyskinesia. Many of these patients develop the disease at a slower rate however, enabling doctors more time to switch the patient to an alternative if indicated.

About Antipsychotics

Antipsychotic drugs used in the treatment of mental illness (also known as neuroleptics) operate on the nervous system's dopamine receptors. Dopamine is a natural chemical substance produced by the brain that controls muscle movement as well as emotions and cognitive functions. The problem in simple terms is that it has been difficult to develop neuroleptic medications targeted toward dopamine receptors that control mood and emotion without affecting those that control muscle function - and this is what causes tardive dyskinesia.

Neuroleptics

Various Classifications

The two broad categories of "typical/first generation" and "atypical/second-third generation" neuroleptics are broken down into subcategories as well. First generation neuroleptics include:

Butyrophenones
Phenothiazines
Thiothixene
Zulcopenthixol

Second and third neuroleptics include:

Clozapine
Olanzipine
Risperidone
Quetiapine
Ziprasidone
Amisulpride
Asenapine
Paliperidone
Apiprazole

Tetrabenzine is another substance used to treat mental illness, although it is not actually an antipsychotic medication. It has been used to treat similar movement disorders such as Huntington's Disease and Tourette syndrome, but is not in and of itself a neuroleptic.

A Lack of Data

Another problem is that relatively little research has been done on tardive dyskinesia, including comparisons of the effects of various drugs. In 2000, Dr. John Kane M.D. published his own study which pointed out that although a great deal of attention had been "directed toward the question of whether or not any specific antipsychotic drug or drug class differs from others in the propensity to produce TD," most of the available data had been derived from animal studies. He concluded that "at the present time, there are no compelling data from prospective clinical studies that any currently available antipsychotic drug has a lower risk for tardive dyskinesia, with the possible exception of clozapine [a second-generation neuroleptic]."

What About Clozapine?

Dr. Kane went on to make a case for clozapine, administered adjunctly with another antipsychotic known as sulpiride, as posing the lowest risk for patients developing tardive dyskinesia. Unfortunately, sulpride is not approved for use outside of Japan and the European Union.

A more recent study, carried out between the Harvard Medical School and Beth Israel-Deaconess Medical Center in Boston in 2006 found that second and third-generation neuroleptics, while putting patients at lower risk for developing dystonia, parkinsonism and akathisia, may not necessarily mean that patients are at a lower risk for developing tardive dyskinesia. At best, these newer drugs may increase the time between exposure to the drugs and onset of symptoms as noted above.

Treating Symptoms

There are medications that when used in combination with, or after a neuroleptic regimen, may help to decrease symptoms. These include:

Melatonin
Trihexyphenidyl
Reserpine
Proprandol
Clondine
Baclofen
Diazepam
Clonazepam
Valporic acid

Of the list above, the last one is actually an antiseizure medication, while the two preceding it are sedatives.