Schizophrenia is a severe psychiatric disorder often associated with cognitive impairment and affective, mainly depressive, symptoms. Antipsychotic medication is the primary intervention for stabilization of acute psychotic epi sodes and prevention of recurrences and relapses in patients with schizophrenia. Typical antipsychotics, the older class of antipsychotic agents, are currently used much less frequently than newer atypical antipsychotics. Therapeutic drug monitoring (TDM) of antipsychotic drugs is the specific method of clinical pharmacology, which involves measurement of drug serum concentrations followed by interpretation and good cooperation with the clinician. TDM is a powerful tool that allows tailor-made treatment for the specific needs of individual patients. It can help in monitoring adherence, dose adjustment, minimizing the risk of toxicity and in cost-effectiveness in the treatment of psychiatric disorders. The review provides complex knowledge indispensable to clinical pharmacologists, pharmacists and clinicians for interpretation of TDM results.
Purpose
Antipsychotic efficacy in schizophrenia depends on its availability in the body. Although therapeutic outcomes remain still far from satisfactory, therapeutic drug monitoring is not a common part of clinical practice during treatment with long-acting injectable antipsychotics (LAI AP). The real effectiveness of LAI AP is thus uncertain.
Patients and Methods
We made a retrospective evaluation of plasma levels of LAI AP. Collection of blood samples was performed just before the drug application and one week later. Forty patients with a stabilized clinical condition and steady-state plasma levels were included.
Results
In the observed cohort of patients, flupentixol decanoate (n = 23) was the most often used drug, followed by fluphenazine decanoate (n = 7), haloperidol decanoate (n = 5), paliperidone palmitate (n = 3), and risperidone microspheres (n = 2). Just 5 of 40 patients were treated with a monotherapy. In the period before the application, 60% of the patients did not reach the therapeutic reference range (TRR) and 20% of the patients had an undetectable plasma level. At the time of collection of the second blood samples performed after 7 days, 24% of the patients were under the TRR.
Conclusion
We have found a surprisingly high incidence of plasma levels under the TRR in patients treated with LAI AP. Notwithstanding individual variability in pharmacokinetics, it seems that LAI AP may be underdosed in usual clinical practice.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.