Which of the following agents may cause tremors as a side effect and, thus, should be used with caution in patients with Parkinson's disease, even though it is also indicated for the treatment of dementia associated with Parkinson's disease?

Correct Answer: C

Rationale: Rivastigmine, an acetylcholinesterase inhibitor, treats Parkinson's disease dementia by enhancing cholinergic function, improving cognition. However, increased acetylcholine can exacerbate tremors, a core Parkinson's symptom, by disrupting dopamine-acetylcholine balance in the basal ganglia, requiring cautious use. Benztropine, an anticholinergic, reduces tremors, not causes them. Rotigotine, a dopamine agonist, improves motor symptoms. Dimethyl fumarate manages MS, not Parkinson's dementia, and lacks tremor association. Rivastigmine's benefit in dementia must be weighed against its potential to worsen tremors, making it the drug needing careful monitoring in this context.

Correct Answer: B

Rationale: ADHD in girls often presents as anxiety/withdrawal, versus boys' hyperactivity-per research-though diagnosis favors boys. It's not bipolar-mania/depression differ. Boys dominate diagnosis stats. It's early, not late, onset. Gender presentation accuracy reflects ADHD nuance.

Correct Answer: B

Rationale: Diphenhydramine's frequent use risks dizziness , an anticholinergic effect. Appetite enhancement isn't typical. Hypotension and bradycardia are less common. Urinary retention (E) occurs but isn't listed. Dizziness reflects CNS depression from high dosing.

Correct Answer: C

Rationale: Rivastigmine, an acetylcholinesterase inhibitor, treats Parkinson's disease dementia by enhancing cholinergic function, improving cognition. However, increased acetylcholine can exacerbate tremors, a core Parkinson's symptom, by disrupting dopamine-acetylcholine balance in the basal ganglia, requiring cautious use. Benztropine, an anticholinergic, reduces tremors, not causes them. Rotigotine, a dopamine agonist, improves motor symptoms. Dimethyl fumarate manages MS, not Parkinson's dementia, and lacks tremor association. Rivastigmine's benefit in dementia must be weighed against its potential to worsen tremors, making it the drug needing careful monitoring in this context.

Correct Answer: B

Rationale: Pharmacodynamics refers to the study of the biochemical, physiological, and behavioral effects of drugs on the body and their mechanisms of action. It specifically focuses on the drugs' actions at the receptor site and how these actions lead to specific responses in the body. This includes understanding how drugs interact with target receptors, enzymes, and other molecular targets within the body to produce their effects. Pharmacodynamics also involves studying the relationship between the drug concentration and the magnitude of the response it elicits, as well as factors influencing the variability in individual responses to a drug. In summary, pharmacodynamics is crucial for understanding how drugs work in the body and how they produce their therapeutic or adverse effects.