Should patients taking Clozaril (clozapine) be on vitamin B supplementation?

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Last updated: March 19, 2025View editorial policy

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From the Guidelines

Patients taking Clozaril (clozapine) should be on vitamin B supplementation, particularly vitamin B12 and folate, to reduce the risk of stroke and other health complications. The evidence from a recent study published in 2022 1 suggests that B vitamins, including B12, can reduce the risk of ischemic stroke by 43%. Additionally, the study highlights the importance of monitoring and treating biochemical and metabolic B12 deficiency, which is common in patients with stroke. The recommended supplementation might include a daily B-complex vitamin containing 100% of the daily value of B vitamins, or specific supplementation with vitamin B12 (1000-2000 mcg daily) and folate (400-800 mcg daily). Some key points to consider when recommending vitamin B supplementation for patients taking Clozaril include:

  • Monitoring vitamin B levels periodically through blood tests to ensure adequate levels
  • Discussing supplementation with the healthcare provider to determine the best course of treatment
  • Considering the potential benefits of reducing stroke risk and improving overall health outcomes
  • Being aware of the potential for Clozaril to lower vitamin B12 levels, which may contribute to side effects or health complications. Another study published in 2020 1 also recommends monitoring and supplementing fat-soluble and water-soluble vitamins, including vitamin B12, in patients with certain medical conditions. However, the most recent and highest-quality study 1 provides the strongest evidence for recommending vitamin B supplementation in patients taking Clozaril.

From the Research

Clozaril (Clozapine) and Vitamin B Supplementation

There is no direct evidence in the provided studies to suggest that patients taking Clozaril (clozapine) should be on vitamin B supplementation.

  • The studies primarily focus on the risk of clozapine-associated agranulocytosis and the importance of white blood cell monitoring 2, 3, 4, 5, 6.
  • None of the studies mention vitamin B supplementation as a recommendation for patients taking clozapine.
  • The discussions revolve around the management and monitoring of clozapine-induced agranulocytosis, including the frequency of blood tests and the thresholds for discontinuing treatment 2, 3, 4, 6.
  • One study explores the impact of changing the timing of complete blood count sampling on white blood cell and absolute neutrophil count values in clozapine recipients 5, but does not address vitamin supplementation.

Therefore, there are no research papers to assist in answering this question regarding vitamin B supplementation for patients taking Clozaril (clozapine).

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Clozapine and agranulocytosis: re-assessing the risks.

Australasian psychiatry : bulletin of Royal Australian and New Zealand College of Psychiatrists, 2013

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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