Final answer:
The most widely used second-generation antipsychotic drug is Clozaril (clozapine), which is particularly effective in treating schizophrenia when other medications are not suitable.
Step-by-step explanation:
The most widely used second-generation antipsychotic drug is Clozaril, also known by its generic name, clozapine. Clozapine is often used when other antipsychotics do not work or cause intolerable side effects. It is particularly effective in managing symptoms of schizophrenia and decreasing the risk of recurrent psychotic episodes. Clozapine works by targeting various neurotransmitter receptors in the brain, including dopamine and serotonin receptors, to reduce psychotic symptoms.
While Prozac is a well-known antidepressant and part of the selective serotonin reuptake inhibitors (SSRIs) class, it is not an antipsychotic. Thorazine, or chlorpromazine, is indeed a first-generation antipsychotic, and Xanax—an anxiolytic—is part of the benzodiazepine class and used primarily to treat anxiety disorders. Hence, the correct answer to the question is (a) Clozaril.