What is the last resort drug for schizophrenia?

Could you elaborate on what the last resort drug for schizophrenia might be? Is there a specific medication that is typically prescribed when other treatments have failed? How effective is this last resort drug in managing the symptoms of schizophrenia, and what are the potential side effects or risks associated with its use? Understanding the specifics of this treatment option would be invaluable for those struggling with schizophrenia and their loved ones.