Which of the following actions most likely mediated the reduction in the patient's tremor?

Correct Answer: B

Rationale: The correct answer is B because inhibiting the abnormally high cholinergic tone in the striatum can help reduce tremors. The striatum plays a key role in motor control, and an imbalance between cholinergic and dopaminergic signaling can lead to tremors. By inhibiting the excessive cholinergic activity, the balance is restored, resulting in reduced tremor. A: Inhibition of levodopa metabolism in the striatum wouldn't directly affect tremors as levodopa is a precursor to dopamine. C: Activation of dopaminergic receptors in the striatum may help with motor control but wouldn't specifically address the cholinergic imbalance causing tremors. D: Blockade of β adrenoceptors in skeletal muscle is unrelated to the striatum and cholinergic signaling involved in tremors.

Correct Answer: A

Rationale: The correct answer is A: Haloperidol and clonazepam. Haloperidol is an antipsychotic medication used to treat acute psychotic states, while clonazepam is a benzodiazepine commonly used to manage seizures. The combination is appropriate as it addresses both the acute psychotic symptoms and the history of seizures in the patient. Explanation for incorrect choices: B: Chlorpromazine and lamotrigine - Chlorpromazine is an antipsychotic, but lamotrigine is primarily used for mood disorders, not seizures. C: Clozapine and ethosuximide - Clozapine is an antipsychotic, but ethosuximide is used to treat absence seizures, not generalized seizures. D: Thioridazine and ethosuximide - Thioridazine is an antipsychotic, but ethosuximide is not commonly used for seizures in adults.

Correct Answer: B

Rationale: The correct answer is B: Risperidone. Risperidone is an atypical antipsychotic known to cause side effects such as abnormal breast growth (gynecomastia) due to its effects on hormone levels. Haloperidol (A) is a typical antipsychotic with a lower likelihood of causing gynecomastia. Amitriptyline (C) is a tricyclic antidepressant that does not typically cause gynecomastia. Buspirone (D) is an anxiolytic medication that is not associated with gynecomastia. Therefore, based on the patient's symptoms, the most likely culprit is Risperidone due to its known side effect profile.

Correct Answer: C

Rationale: The correct answer is C: Inhibition of serotonin transporter. This mechanism of action would be appropriate for this patient as it increases serotonin levels in the synaptic cleft, which can help alleviate symptoms of depression. Monoamine oxidase A inhibition (Choice A) is used for atypical depression. Serotonergic receptor blockade (Choice B) can worsen depression symptoms. Blockade of β receptors (Choice D) is used for conditions like hypertension, not depression. In summary, choice C is the most suitable for treating depression by increasing serotonin levels, while the other choices are either ineffective or potentially harmful for this condition.

Correct Answer: D

Rationale: The correct answer is D: Chlorpromazine. The patient reported symptoms are likely extrapyramidal side effects, such as tremors, muscle rigidity, and akathisia, which are common with typical antipsychotics like chlorpromazine. Lithium (A) is used for bipolar disorder, not associated with these side effects. Amitriptyline (B) is a tricyclic antidepressant, known for sedation and anticholinergic effects. Fluoxetine (C) is a selective serotonin reuptake inhibitor, not known for causing extrapyramidal symptoms. Therefore, based on the symptoms described, chlorpromazine is the most likely culprit.