For a client using benztropine, what adverse effect should the nurse specifically monitor?

When monitoring a client using benztropine, the nurse should specifically watch for tachycardia. Benztropine is an anticholinergic medication often used to manage symptoms of Parkinson's disease and extrapyramidal symptoms caused by antipsychotic medications. One common adverse effect of anticholinergic agents, including benztropine, is the increased heart rate, or tachycardia, which occurs due to the drug’s impact on the autonomic nervous system.

By blocking acetylcholine receptors, benztropine can lead to a reduced parasympathetic nervous system activity, resulting in various side effects, including an increased heart rate. Therefore, monitoring for tachycardia is critical to ensure that the client's cardiovascular status remains stable and to intervene if necessary.

While other side effects such as dry mouth, weight gain, and insomnia can occur with the use of benztropine, tachycardia is particularly notable as a direct result of its anticholinergic properties and is important for the nurse to monitor closely to prevent more serious complications.