Clozaril (generic name clozapine) is an atypical antipsychotic approved to treat schizophrenia. The drug is also used “off-label” to treat bipolar disorder and schizoaffective disorder. While it can be effective in treating the symptoms of schizophrenia, the drug may cause severe and sometimes life-threatening side effects.
FDA “Black Box” Warning for Numerous Side Effects
Certain Clozaril side effects are so harmful to the person, that they have prompted a special warning by the FDA called a “black box” warning. In fact, clozapine has five black box warnings:
- Myocarditis and cardiomyopathy
- Orthostatic hypotension, bradycardia, syncope
- Increased risk of death in elderly patients with dementia
Agranulocytosis is a disorder of the blood in which there are too few white blood cells. This side effect of clozaril is also referred to as neutropenia. White blood cells are a key component of the immune system. As such, people with neutropenia are at an increased risk for infections. This side effect of clozapine is with such seriousness, that people who receive clozapine must have their blood tested for neutropenia periodically. In fact, clozapine is only available through a distribution system that ensures blood monitoring. If neutropenia does occur, clozapine is stopped and white blood cell count returns to norm level.
One of the major neurological Clozaril side effects is seizures. Seizures are abnormal increases in brain activity that may lead to uncontrollable physical movements, convulsions, and loss of consciousness. People who have a history of seizures, have epilepsy, or any condition in which seizures may occur, are often not able to take clozapine because of this ornery physical reaction.
Clozapine lowers the seizure threshold. This effect seems to be dose dependent. In other words, the risk of seizure increases as the dose of Clozaril increases.
Myocarditis and Cardiomyopathy
Myocarditis and cardiomyopathy are related conditions that involve inflammation of the heart and cause damage to the heart muscle. These conditions can be fatal. Clozaril adverse effects are more likely to occur within the first month of starting the drug. There is a small risk of myocarditis and cardiomyopathy at any point when the drug is use. If signs or symptoms of the Clozaril side effects occur, talk to your doctor and stop taking the medication.
Orthostatic Hypotension, Bradycardia, Syncope
These clozapine adverse effects are interrelated. The drug may decrease both heart rate and blood pressure, especially when someone rises from a seated or reclining position. When there is not enough blood flow to the brain, patients may become lightheaded (pre-syncope) or actually faint (syncope). These Clozaril side effects are most likely to occur when the drug is started or the dosage is changed.
Increased Risk of Death in Elderly Patients with Dementia
Atypical antipsychotics (including Clozaril), increase the risk of death in elderly patients with dementia. Dementia is a condition that causes hallucinations and delusions. As such, clozapine is usually not used to treat dementia-related psychosis.
Other Clozaril Side Effects
Compared to black box warnings, other Clozaril side effects are relatively minor. The most common Clozaril adverse effects are tachycardia (rapid heart rate), drowsiness, dizziness, insomnia, weight gain, nausea, vomiting, constipation, and sialorrhea (drooling or excessive saliva production).
To have an understanding on how you will react to Clozaril, preferably before using it, PGx testing with Rxight® can provide the solution. The Rxight® panel also includes hundreds of other medications across over 50 pharmacological classes.