Schizophrenia Q 17
Which of the following is one of the advantages of the newer antipsychotic medication risperidone (Risperdal)?
A. The absence of anticholinergic effects.
B. A lower incidence of extrapyramidal effects.
C. Photosensitivity and sedation.
D. No incidence of neuroleptic malignant syndrome.
Correct Answer: B. A lower incidence of extrapyramidal effects
Risperdal has a lower incidence of extrapyramidal effects than the typical antipsychotics. SGAs have loose binding to D2 receptors and can quickly dissociate from the receptor, potentially accounting for the lower likelihood of causing extrapyramidal symptoms (EPS). Moreover, SGAs have agonism at the 5HT1A receptor. Serotonin and norepinephrine reuptake inhibition are potential mechanisms by which risperidone is postulated to produce antidepressant effects. The improvement of positive symptoms is thought to be accomplished through the blockade of D2 receptors specifically in the mesolimbic pathway.
Option A: Risperdal does produce anticholinergic effects and neuroleptic malignant syndrome can occur. Of note, risperidone does not cause anticholinergic effects, which may be of benefit for patients in certain populations including the elderly with dementia.
Option C: Photosensitivity isn’t an advantage. Although there are no mandatory requirements for therapeutic drug monitoring (TDM) with risperidone, monitoring plasma concentrations for this medication is strongly recommended by European guidelines because of data that shows interdependent variability. Therapeutic monitoring can be of benefit to assess compliance and in identifying low drug concentrations that may be low resulting in therapeutic failure. Also, monitoring the drug level can aid in evaluating for potential drug interactions and side effects.
Option D: Serious side effects of antipsychotic medications (like risperidone) can include neuroleptic malignant syndrome (NMS). Although the pathogenesis of NMS is not clear, it is a life-threatening condition that can manifest with altered mental status, fever, “lead pipe” rigidity, and autonomic instability including hypertension, tachypnea, and tachycardia.