From my experience and observation as a mental health nurse, I remember a 20-year-old male patient who was admitted to my facility with a diagnosis of schizophrenia, self-harming behaviors, and substance abuse. This patient had a long history of using fentanyl, methamphetamine, and street drugs like Mexican Percocet’s. He has been admitted numerous times to our facility for substance abuse detox. This patient had been on several dosages of Clozapine which was prescribed by the provider to help with his acute case of mental illness. A week after starting his initial Clozapine medication, this patient was complaining of discomfort, chest pain and will explain to the staff that his pain was getting worse daily. The physician ordered EKG to check the activity of his heart.
Pharmacodynamics
Clozapine is a serotonin antagonist, with strong binding to 5-HT 2A/2C receptor subtype. It also displays strong affinity to several dopaminergic receptors but shows only weak antagonism at the dopamine D2 receptor, a receptor commonly thought to modulate neuroleptic activity. Clozapine also binds to D1, D3, and D5 receptors, and has a high affinity for the D4 receptor (McEvoy, 2018). Researchers shows that it includes the limbic system.
Pharmacokinetics
Clozapine is absorbed quickly, first-pass metabolism reduces its bioavailability to 60 to 70 percent of the administered dose; food has little effect on the bioavailability of clozapine (Patuszynski & Applegate, 2017). The eliminated half-life of clozapine averages a period of 14 hours under certain conditions, but there is considerable variability across individuals. For example, it depends on each individual own metabolism and its underlying factors (McEvoy, 2018).
Care plan
Because clozapine has an increased incidence of clozapine-induced myocarditis as well as cardiomyopathy. Patients who are currently taking clozapine will need to be monitored closely by a cardiologist. Staff must educate the patient regarding the risk that are involved with this medication. “We need to understand that there should be standardized and mandatory plans of care which should include troponin levels as well as EKGs and echocardiograms at various times during inpatient stays” (Kir et al., 2020). “Other factors to consider would be airway clearance due to excessive salvation and neutropenia” (Okada et al., 2020). Careful patient monitoring is essential when taking clozapine therapy. It is important to educate patient to keep to their lab appointments where they could monitor blood levels.
References
Kır, Y., Baskak, B., Kuşman, A., Sayar-Akaslan, D., Özdemir, F., Sedes-Baskak, N., Süzen, H.
S., & Baran, Z. (2020). The relationship between plasma levels of clozapine and N-desmethyclozapine as well as M1 receptor polymorphism with cognitive functioning and associated cortical activity in schizophrenia. Psychiatry Research: Neuroimaging, 303.
Okada, T., Kumakura, J., Yasuda, M., & Suda, S. (2020). Treatment-resistant schizophrenia
successfully maintained with brexpiprazole following abrupt withdrawal of clozapine due to neutropenia. Asian Journal of Psychiatry, 47.
Patuszynski, D., & Applegate, P. M. (2017). Suspected Clozapine-Induced Cardiomyopathy and
Heart Failure With Reduced Ejection Fraction. Federal practitioner: for the health care professionals of the VA, DoD, and PHS, 34(4), 20–22.
