The Syndrome
Tardive dyskinesia is a neurological syndrome caused by long term use of neuroleptic drugs. The behavior associated with tardive diskinesia is repetitive and involuntary movements with no apparent motive or objective. This class of medication is usually prescribed for psychiatric or neurological disorders, but is also used with patients suffering from certain gastrointestinal problems.
Some of the movements characterizing this disorder include tongue protrusion, lip smacking, grimacing, puckering the lips and rapid blinking of the eyelids. In some cases rapid movements of the limbs and trunk have been observed. Involuntary rapid, busy movements of the fingers may look as if the patient is mimicking the usage of a computer or typewriter keyboard.
Treatment
There is no standardized treatment regimen for this condition. The obvious first step is discontinuing or abridging the use of the catalyst medication. In some patients other drugs may be substituted, in some just discontinuing the medication may be feasible and for some discontinuing the medication is not an option. The symptoms may continue long after use of the medication has ended; according to the National Institute of Neurological Disorders and Stroke (NINDS), one of the National Institutes of Health, “with careful management, some symptoms may improve and/or disappear with time.”
The Causes
The medications that are associated with this syndrome are primarily tranquilizers and antipsychotics. The class of antipsychotic medications known as “typical” antipsychotics is designed to affect the dopamine level in the patient. Haldol is perhaps the best known of this class. “Atypical” antipsychotics such as Clorazil impact dopamine and other neurotransmitters such as serotonin.
Long term use of these medications show high rates of the tardive diskinesia syndrome. One study from the Yale University School of Medicine suggests that nearly a third of patients who have taken major tranquilizers for five years or more have developed tics. (Journal of Clinical Psychiatry 54 (1993): 133-139)
Just recently the FDA issued a public health advisory that included a “black box” warning requirement for the gastrointestinal medication metoclopramide, marketed under the names Reglan, Octamide and Maxolon. This medicine is used to accelerate the slow digestion process that affects diabetics and leads to acid reflux, heartburn and vomiting.
The FDA cites evidence that metoclopramide can also cause tardive diskinesia. The connection between the antipsychotics and this gastrointestinal medication is that all of them manipulate the dopamine neurotransmitter to achieve their respective desired effects. Apparently all of them are connected to a serious and sometimes permanent involuntary movement disorder.
