Key takeaways
Haloperidol (Haldol) and olanzapine (Zyprexa) are both antipsychotic medications used to treat schizophrenia, but they belong to different classes. Haloperidol is a typical antipsychotic, while olanzapine is an atypical antipsychotic. Haloperidol is available as an oral tablet, oral liquid, and an injection, either long-acting monthly or short-acting in a hospital setting, and is less likely to cause weight gain. Olanzapine is also available in an oral form and an injectable form, and is more likely to cause weight gain and other metabolic issues like high blood sugar and cholesterol. Olanzapine can also treat bipolar disorder and certain types of depression when combined with fluoxetine (Prozac), whereas haloperidol is primarily used for schizophrenia. Both medications can cause movement-related side effects, but haloperidol has a higher risk of these issues. Additionally, both medications can cause sleepiness, dry mouth, and constipation.
