Experts Brainstorm How to Expand Clozapine Use

The availability of quick, easy-to-use, point-of-care blood tests should help increase the use of clozapine, said a panel of experts at APA’s Annual Meeting in May. However, the rigorous blood monitoring required to check for clozapine-associated neutropenia is not the only reason this proven treatment for treatment-resistant schizophrenia remains underused, they noted. Psychiatrists’ hesitancy and lack of experience using clozapine are even greater barriers.

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Speaking to a packed house, investigators Dan Siskind, Ph.D., M.B.B.S., of the University of Queensland in Australia; Dan Cohen, M.D., Ph.D., of Mental Health Care North-Holland in the Netherlands; Henry Nasrallah, M.D., of St. Louis University School of Medicine; and Jonathan Meyer, M.D., of the University of California, San Diego, shared their experiences prescribing clozapine and discussed available resources for psychiatrists interested in learning more about the medication.

Cohen touched on an issue that concerns many psychiatrists: Physicians who prescribe clozapine are expected to regularly monitor these patients’ blood to ensure they do not exhibit a rapid loss of white blood cells (neutropenia), which can endanger their health. Many clinics may be hesitant to prescribe clozapine because of costs and time involved in blood monitoring.

There are blood tests that can simplify the collection process, Cohen explained. One option might be tabletop, point-of-care blood tests that use a finger prick to collect capillary blood (as opposed to venous blood draws) to quickly assess samples. Cohen conducted a survey study of 70 patients who reported that capillary blood drawing was more convenient and tolerable than traditional blood drawing. It’s also more cost effective, he noted. (His study involved a device developed by the Swedish company Hemocue, and the panel pointed out that U.S. company Athelas received FDA approval last year for a point-of-care, white blood cell test.)

Another approach might be to use dried blood spot sampling, as is done to test for metabolic disorders in newborns. While dried blood spot sampling can assess clozapine drug levels only to determine whether the patient is in a therapeutic range, the test involves a pinprick and some filter paper to collect blood, which can then be sent to a laboratory for analysis.

While the panelists noted that there are other rare side effects associated with clozapine, including myocarditis (inflammation of the heart muscle), constipation, and excess drooling, physicians’ limited experience with clozapine remains a key contributor to underuse.

Siskind encouraged psychiatrists with clozapine experience to share their knowledge with others whenever possible and to get others—including nurses, other clinical staff, even patients—involved in the process as well. “If we can get current users to discuss their experiences, the good and the bad, it could help convince many others,” he said.

As one example of a clozapine-users network, Nasrallah talked about the CURESZ (Comprehensive Understanding via Research and Education into Schizophrenia) Foundation. He established CURESZ in 2016 along with Bethany Yeiser, a patient of Nasrallah’s with schizophrenia who made a full recovery with the help of clozapine. In addition to providing educational lectures about schizophrenia to young adults across the nation, CURESZ has established an international panel of clozapine experts to help guide physicians and their patients. Any physician can access the CURESZ website to find the nearest expert for assistance and potential referral.

Meyer then highlighted a book he recently co-authored that serves as a comprehensive clozapine therapy resource for physicians. “I felt the field needed this more than anything. For all the years clozapine has been used, there has only been one previous textbook on the subject,” he said. And, unfortunately, that previous book quickly became outdated as the clozapine blood-monitoring guidelines were changed right after it was published.

“The clinical evidence is there,” Siskind said in conclusion of his talk. “Clozapine reduces hospitalizations, it reduces mortality, patients like to take it, and it saves hospitals money. We just need to convince providers to overcome their worries about lack of experience and give clozapine a shot.” ■