Benztropine (Cogentin) is used to treat extrapyramidal effects induced by antipsychotics. This drug exerts its effect by:

Correct Answer: B. Blocking the cholinergic activity in the central nervous system (CNS).

This is the action of Cogentin. Benztropine antagonizes acetylcholine and histamine receptors. In the CNS and smooth muscles, benztropine exerts its action through competing with acetylcholine at muscarinic receptors. Consequently, it reduces central cholinergic effects by blocking muscarinic receptors that appear to improve the symptoms of Parkinson disease. Thus, benztropine blocks the cholinergic muscarinic receptor in the central nervous system. Therefore, it reduces the cholinergic effects significantly during Parkinson disease which becomes more pronounced in the nigrostriatal tract because of reduced dopamine concentrations.

• Option A: Anxiety doesn’t cause extrapyramidal effects. Benztropine belongs to the synthetic class of muscarinic receptor antagonists (anticholinergic drug). Thus, it has a structure similar to that of diphenhydramine and atropine. However, it is long-acting so that its administration can be with less frequency than diphenhydramine. It also induces less CNS stimulation effect compared to that of trihexyphenidyl, making it a preferable drug of choice for geriatric patients.
• Option C: Overactivity of acetylcholine and lower levels of dopamine are the causes of extrapyramidal effects. It is also useful for drug-induced extrapyramidal symptoms and the prevention of dystonic reactions and acute treatment of dystonic reactions. Furthermore, benztropine has further off-label use as it can treat chronic sialorrhea occurring in developmentally-disabled patients. Also, several clinical studies worked on using benztropine in managing intractable hiccups.
• Option D: Benztropine doesn’t increase norepinephrine in the CNS. Benztropine overdose can cause an anticholinergic toxidrome, which, in its role, may require supportive care. Commonly, the risk assessment for benztropine overdose can take place as soon as 6 hours after overdose ingestion, and toxicity effects may last variably between 12 hours to 5 days at most. The most crucial step of proper detection of benztropine overdose starts from carrying out intensive and inclusive investigations. For example, ECG can be an essential assessment tool using 12 leads during testing. Also, monitoring the acetaminophen concentrations as well as blood glucose concentrations can become a useful method for toxicity investigations if the toxicant is unknown.