LAS VEGAS –
“But this does not seem to always be the case, because there is still a risk of TD, and we need to monitor for it,” Dr. Correll, professor of psychiatry and molecular medicine at The Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York, said during an annual psychopharmacology update held by the Nevada Psychiatric Association. “It is important to minimize the risk of TD by educating patients and caregivers about the risks of and alternatives to antipsychotic medication and early signs of TD.”
First described in 1957, TD is characterized by involuntary repetitive but irregular movements, mostly in the oral, lingual, and buccal regions – such as tongue protruding, puckering, chewing, and grimacing. Less often, there are movements in the hands, legs, feet, and torso. Symptoms can include mannerisms, stereotypies, tics, myoclonus, dystonias, tremor, and akathisia. “TD can be severe, persistent, and have medical and psychosocial consequences,” Dr. Correll said. “It can occur in untreated patients, but treatment with dopamine blocking agents – antipsychotics and metoclopramide – increases risk for TD.”
Differential diagnoses to consider include morbus Huntington, benign familial Chorea, and Sydenham’s Chorea. Less frequent causes of TD include metabolic conditions such as uremia, hyponatremia, hypernatremia, hypoparathyroidism, and hyperparathyroidism. “Those would need to be ruled out during the physical exam,” he said. There can also be inflammatory causes of TD such as herpes simplex virus, varicella, measles, mumps, and rubella.
A standard measure for TD diagnosis is the Abnormal Involuntary Movement Scale (AIMS), an observer-rated 12-item anchored scale that takes 5-10 minutes to administer. However, the AIMS on its own does not diagnose TD. In 1982, researchers developed three diagnostic criteria for TD: At least 3 months of cumulative antipsychotic drug exposure; presence of at least moderate abnormal involuntary movements in one or more body area(s) or mild movements in two or more body areas, and absence of other conditions that might produce involuntary movements (Arch Gen Psychiatry 1982;39:486-7).
The impact of TD on everyday functioning depends on anatomic location as well as severity, Dr. Correll continued. The condition can cause impairments to speech, verbal communication, dentition, temporomandibular joint pain/myalgia, swallowing difficulties, and fine motor skills including instrumental activities of daily living and written communication. Truncal and lower extremity TD can affect gait, posture and postural stability, strength, power flexibility, physical capacity, and one’s ability to exercise. “There are also psychological impairments,” he said. “Patients can develop different awareness so they become self-conscious; there can be cognitive abnormalities, and they can become more anxious or [have an] increased sense of paranoia, isolation, stigma, social and/or educational/vocational impairment.”
According to research by Dr. Correll and colleagues, unmodifiable patient-related risk factors for TD include older age, female sex, and being of white or African descent (J Neurol Sci 2018 June 15; 389:21-7). Unmodifiable illness-related risk factors include longer duration of illness, intellectual disability and brain damage, negative symptoms in schizophrenia, mood disorders, cognitive symptoms in mood disorders, and gene polymorphisms involving antipsychotic metabolism and dopamine functioning. Modifiable comorbidity-related factors include diabetes, smoking, and alcohol/substance abuse, while modifiable treatment-related factors include dopamine receptor blockers, higher cumulative and current antipsychotic dose or plasma levels, early parkinsonian side effects, treatment-emergent akathisia, and anticholinergic co-treatment. In a meta-analysis of 41 studies that aimed to determine the prevalence of TD, the mean age of the 11,493 patients was 43, 66% were male, and 77% had schizophrenia spectrum disorders (J Clin Psychiatry. 2017 Mar;78:e264-78). The global mean TD prevalence was 25%, but the rates were lower with patients on current treatment with second-generation antipsychotics compared with those on first-generation antipsychotics (21% vs. 30%, respectively).
According to Dr. Correll, strategies for preventing TD include confirming and documenting the indication for dopamine antagonist antipsychotic medications, using conservative maintenance doses, and considering the use of SGAs, especially in those at high risk for EPS (extrapyramidal symptoms). “Don’t go too high [with the dose],” he said. “Stay below the EPS threshold. Inform patients and caregivers of the risk of TD and assess for incipient signs regularly using the AIMS.”
Treatment options include discontinuing antipsychotics, adjusting their dose, or switching patients from a first-generation antipsychotic to a second-generation antipsychotic. Supplementation with antioxidants/radical scavengers such as vitamin E, vitamin B6, ginkgo biloba, and fish oil “can be tried, but have limited evidence, as is the case for melatonin.” Other options include clonazepam, amantadine, donepezil, and tetrabenazine, a reversible and specific inhibitor of vesicular monoamine transporter-2 (VMAT-2), a transporter that packages neurotransmitters (preferentially dopamine) into vesicles for release into the synapse and was approved in 2008 as an orphan drug for the treatment of choreiform movements associated with Huntington’s disease. “Neurologists have using tetrabenazine off-label for TD, but in schizophrenia and other psychiatric care, we rarely use it because it has to be given three times a day and it has a black box warning for depression and suicidality,” he said.
Dr. Correll noted that the Food and Drug Administration approval of two more recent VMAT-2 inhibitors – deutetrabenazine (Austedo) and valbenazine (Ingrezza) – provides an evidence-based care option for the effective management of TD. Deutetrabenazine requires titration over several weeks and twice-daily dosing, while valbenazine can reach the maximum dose by the beginning of week 2 and is dosed once daily. Deutetrabenazine should be taken with food, which is not required valbenazine.
“Both VMAT-2 inhibitors are generally well tolerated and have a positive benefit-risk ratio,” he said. “Both are recommended by the APA guidelines as the preferred and only evidence-based treatment for TD.”
Dr. Correll reported that he has received honoraria from and has been an advisory board member for numerous pharmaceutical companies. He has also received grant support from Janssen, the National Institute of Mental Health, the Patient Centered Outcomes Research Institute, Takeda, and the Thrasher Foundation.