Severe granulocytopenia in a patient on long-term use of clozapine and with COVID-19

Exploring the Impact of COVID-19 Vaccination on Patients Taking Clozapine

Objective

Individuals with serious mental illness (SMI) are recognized to be among the highest risk patients to experience more severe symptoms of COVID-19, not only due to poor baseline health and associated disparity, but also due to medications prescribed to manage their illness that are known to compromise immunity even further. Clozapine, a gold standard antipsychotic used in the treatment for refractory schizophrenia, is considered to be the antipsychotic with the greatest risk of compromising immunity due to its potential to cause blood dyscrasia, including leukopenia and rarely, but potentially, agranulocytosis. The objective of this study is to determine if there is any potential hematological consequence for the use of COVID-19 messenger ribonucleic acid (mRNA) vaccines or the impact of active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients receiving clozapine therapy. Since there is controversy over the rate of vaccine hesitancy in patients with SMI, we also examined the rate of vaccine acceptance in our subject population.

Design

This study was a retrospective chart review conducted at a 160-bed state psychiatric inpatient hospital in upstate New York evaluating the impact of COVID-19 vaccination, SARS-CoV-2 infection, and vaccine acceptance in patients prescribed clozapine.

Results

Both the administration of COVID-19 mRNA vaccines and SARS-CoV-2 infection did not appear to significantly influence the hematologic values that are monitored by the United States (US) Food and Drug Administration (FDA) to ensure safe use of clozapine. When offered vaccination, most patients hospitalized for SMI were willing to accept it.

Conclusion

With the likelihood of COVID-19 mRNA vaccinations becoming a recommended routine vaccination, requiring periodic boosters, patients receiving clozapine therapy have been observed to not be at higher risk of adverse hematological consequences when the mRNA vaccine is administered. Furthermore, inpatient psychiatry settings should be considered an optimal site of vaccination to improve vaccination efforts in our communities.

Neutropenia after the coadministration of clozapine and nirmatrelvir-ritonavir in a patient with SARS-CoV-2 infection: A case report with a literature review

BACKGROUND

Schizophrenia is considered one of the major risk factors for mortality from SARS-CoV-2 infection. Early antiviral treatment is important to decrease the risk of mortality. Currently, Paxlovid (nirmatrelvir-ritonavir) has been widely used in SARS-CoV-2 patients with risk factors. However, drug-drug interactions with anti-psychotics are prominent and complicated.

CASE PRESENTATION

We report a clozapine-treated patient with SARS-CoV-2 infection who developed neutropenia after coadministration with Paxlovid. In this case, clozapine was used for over 15 years, without neutropenia development. However, severe neutropenia (absolute neutrophil count = 523/μl) developed 3 days after the coadministration of Paxlovid 2 doses per day, valproic acid 1,000 mg per day and clozapine 100 mg per day. The development of neutropenia may be attributed to the complicated interaction among Paxlovid, SARS-CoV-2 infection, valproic acid, fluvoxamine and clozapine.

CONCLUSIONS

Neutropenia is a rare but life-threatening event if a concomitant infection occurs. The risk may increase during SARS-CoV-2 infection and the coadministration of clozapine and Paxlovid. Although the exact causes of neutropenia in this patient are not fully clear, the white blood cell count and absolute neutrophil count should be closely monitored during the administration of Paxlovid in clozapine-treated patients with SARS-CoV-2 infection.