A 25-year old man with a psychotic illness, was treated with haloperidol 30mg/day. On the third day he developed pacing, and inability to sit still at one place. The medication likely to be helpful is:
First, I need to recall what haloperidol is. Haloperidol is a typical (first-generation) antipsychotic. It's a high-potency antipsychotic, meaning it has a higher affinity for dopamine D2 receptors, which contributes to extrapyramidal side effects (EPS). The symptoms described here—pacing, restlessness—are classic signs of akathisia. Akathisia is a type of EPS that occurs due to dopamine receptor blockade, typically in the nigrostriatal pathway.
So the core concept here is the management of extrapyramidal side effects caused by antipsychotics. The correct treatment for akathisia would be a medication that can counteract the dopamine blockade. Benzodiazepines are often used because they have antianxiety and muscle-relaxant properties, which can help with the physical restlessness. Alternatively, anticholinergic medications like benztropine or diphenhydramine are used for other EPS like dystonia or parkinsonism. However, for akathisia, benzodiazepines (like lorazepam) are preferred over anticholinergics.
Now, looking at the options (even though they're not listed here), the correct answer would be a benzodiazepine. If the options included lorazepam, that would be the choice. Alternatively, switching to a lower potency antipsychotic or adding a beta-blocker like propranolol might also help, but benzodiazepines are first-line for acute management.
The incorrect options would likely include other antipsychotics (which would worsen EPS), anticholinergics (less effective for akathisia), or maybe something like a dopamine agonist (but those aren't typically used for EPS management). Also, increasing the antipsychotic dose would make it worse, so that's definitely wrong.
Clinical pearl: Remember that akathisia is a common EPS with high-potency antipsychotics like haloperidol. Early recognition and treatment with benzodiazepines can prevent it from becoming chronic. Also, propranolol is another option, but benzodiazepines are first-line.
**Core Concept**
This question tests the management of extrapyramidal side effects (EPS), specifically akathisia, caused by high-potency typical antipsychotics like haloperidol. Akathisia results from dopamine D2 receptor blockade in the nigrostriatal pathway, leading to restlessness and motor agitation.
**Why the Correct Answer is Right**
The patient’s symptoms (pacing, inability to sit still) are classic **akathisia**, a common EPS of haloperidol. Benzodiazepines (e.g., lorazepam) are first-line treatments for acute akathisia. They reduce central nervous system overactivity and muscle tension via GABAergic enhancement. Alternatively, beta-blockers like propranolol may help, but benzodiazepines are preferred for rapid relief.
**Why Each Wrong Option is Incorrect**
**Option A:** Anticholinerg