Clozapine-Related Thromboembolic Events

Area of Science:

• Pharmacology
• Clinical Medicine
• Psychiatry

Background:

• Clozapine is a critical atypical antipsychotic for treatment-resistant schizophrenia.
• Venous thromboembolism (VTE) is a rare, potentially fatal side effect associated with clozapine use.
• Understanding the VTE risk in clozapine users is crucial for patient safety.

Purpose of the Study:

• To summarize current evidence on the risk of VTE in patients using clozapine.
• To analyze case reports of VTE onset in clozapine users over the last two decades.
• To identify patient characteristics, risk factors, and outcomes associated with clozapine-induced VTE.

Main Methods:

• Conducted a literature search of PubMed (MeSH) and Google Scholar for the past 20 years.
• Included human studies and case reports focusing on clozapine use at the time of VTE onset.
• Analyzed 42 case reports for demographic data, clozapine dosage, VTE onset timing, comorbidities, concomitant medications, and outcomes.

Main Results:

• The average age of affected patients was 42.9 years, with a male predominance (71.43%).
• VTE onset typically occurred within the first six months of clozapine use (71.8%), with an average dose of 285.62 mg/day.
• A high percentage of patients had comorbidities (70.37%) and VTE risk factors (87.5%); mortality was 32.5%, with clozapine discontinuation in 60% of cases.

Conclusions:

• VTE associated with clozapine can occur across a wide dose range, with a notable incidence within the first six months of treatment.
• Patients prescribed clozapine often have pre-existing risk factors for VTE, necessitating careful consideration of this risk.
• Further research is needed to clarify the precise risk of VTE in clozapine users and evaluate the efficacy of thromboprophylaxis.