Clozapine Resources

Clozapine may be particularly helpful for people who have ongoing positive symptoms of psychosis, which can include auditory hallucinations or delusions (also known as beliefs that are not true). Sometimes when these symptoms are better under control, it may be easier to work, go to school and have the relationships that people want. Additionally, clozapine may have a unique benefit in reducing the risk of suicide.

While Clozapine is an effective treatment for schizophrenia and similar conditions, there are some risks associated with Clozapine. Clozapine may cause a low white blood cell count (known as neutropenia), cardiac issues such as myocarditis, diabetes or seizures. Clozapine may also cause fatigue, weight gain, drooling or dizziness upon standing. Please contact your doctor if you experience any of these side effects. Your doctor may be able to tell you about treatment options to reduce these side effects or may consider making changes to your medication.

Less than one percent of patients that take clozapine can develop dangerously low neutrophil counts.  Neutrophils are the cells that fight off infection in the body, and if someone has a very low level of neutrophils, they can be vulnerable to infections. When the neutrophil count is regularly monitored, the risk of severe neutropenia is reduced. For the first six months a patient takes clozapine, they must have weekly blood work to check their neutrophil count. Then from months 6 to 12, the blood work is every other week. After 12 months, the blood work is monthly. Your doctor may also check the level of clozapine in your blood, as well as test you for high cholesterol and diabetes.

Your doctor will help select the right dose for you. The usual dose range of clozapine is between 300-600 mg of clozapine per day. The FDA maximum clozapine dose is 900 mg. Some patients may take more or less clozapine, and your doctor may use clozapine levels to help guide the dose. Most patients take clozapine at bedtime because it can make you sleepy, but some patients may take it twice per day. Clozapine is available in a liquid form, tablets you swallow and dissolvable tablets. It is important to take clozapine exactly according to the plan you make with your doctor. If you miss several doses, please talk with your doctor, and the medication might need to be gradually started.

If you miss a dose of clozapine, please take it when you remember. If it is close to the time you would take your next dose, skip the missed dose. Do not take both the missed dose and the next dose. Using a pill box or setting an alarm on your phone can help you remember to take your medication every day. If you miss more than two doses of clozapine, please speak with your doctor.

Please speak with your doctor about your other medications, including herbal supplements and over the counter medications, when you are taking clozapine. If you are planning to become pregnant or are breastfeeding, please also speak with your doctor. Let your doctor know immediately if you are prescribed ciprofloxacin, a antibiotic medication which can increase blood levels of clozapine.

Yes. The COVID-19 vaccines are thought to be safe when given to patients who are on clozapine. If you develop a COVID-19 infection, sometimes this can increase blood levels of clozapine. Please let your doctor know immediately if this happens.

Your doctor may monitor your clozapine level to monitor for the drug's effectiveness and side effects. Your doctor may share the clozapine level with you so you can have a sense of how much clozapine is in your body. The usual therapeutic range of clozapine blood levels is between 350-600 ng/mL. Sometimes people may respond to a clozapine level below 350 ng/mL, and other times people may need greater than 600 ng/mL for a good response. If clozapine levels are too high (>1000 ng/mL) individuals can develop sedation, confusion, seizures and possibly other side effects. Some labs report both a clozapine level and a norclozapine level, but most of the time, your doctor will be looking at the clozapine level to help determine the medication's efficacy and side effects.

Your doctor will work with you to take the lowest possible dose of clozapine that is effective for you. Sometimes people who take clozapine may be on other antipsychotic medications, and you and your doctor may decide to reduce some of these other medications. Some doctors may use clozapine levels to help guide the effectiveness of clozapine. Although some individuals may respond to clozapine at levels <350 ng/mL, if you are still having symptoms, your doctor may increase the clozapine to get a level above 350 ng/mL. Once the level is above 350 ng/mL, some patients notice a response to clozapine after 2-3 weeks.