Medicinal extrapyramidal disorders are common in clinical practice. They are usually caused by side effects of drugs that disrupt the balance of neurotransmitters, mainly altering the activity of dopaminergic systems and the functional state of dopamine receptors. Antipsychotics block the dopamine receptors, thus, they are the first among other psychiatric drugs to cause extrapyramidal symptoms. According to Boloc et al. (2018), “acute EPS constitutes a complex phenotype including several syndromes: akathisia; acute dystonia; and parkinsonism” (p. 1). A fairly detailed assessment of hyperkinetic disorders can be carried out using the Extrapyramidal Symptoms Rating Scale (ESRS). The Abnormal Involuntary Movement Scale (AIMS) is also often used to diagnose and differentiate between extrapyramidal symptoms through the assessment of a patient’s movements.
Both first- and second-generation antipsychotics can cause extrapyramidal symptoms equally. For example, the use of Trifluoperazine or Haloperidol often leads to the development of parkinsonism syndrome, while Metoclopramide and Flunarizine are much less likely to cause it. Neuroleptic parkinsonism is a collective name for a variety of extrapyramidal symptoms, and it usually occurs more often in persons over 40 years of age and is less common in men than in women. However, unlike actual Parkinson’s disease, the tremor caused by these antipsychotics is symmetrical. Usually, for correction of this side effect, M-anticholinergics are used.
The malignant neuroleptic syndrome is another, although rare complication of antipsychotic therapy. In its mechanism lies the blockade of dopamine receptors in the striatum and hypothalamus. The syndrome usually develops in the first days of treatment or after a sharp increase in the dose of Chlorpromazine or Fluphenazine. Quetiapine and Olanzapine are not likely to cause this severe side effect. Most often, the syndrome occurs in young men with the use of long-acting antipsychotics. Treatment guidelines prescribe infusion therapy which is aimed at correcting homeostasis parameters and, first of all, water-electrolyte balance.
References
Boloc, D., Gortat, A., Cheng-Zhang, J. Q., GarcĂa-Cerro, S., RodrĂguez, N., Parellada, M., Saiz-Ruiz, J., Cuesta, M. J., GassĂł, P., Lafuente, A., Bernardo, M., & Mas, S. (2018). Improving pharmacogenetic prediction of extrapyramidal symptoms induced by antipsychotics. Translational Psychiatry, 8(1).