SARS-CoV-2 vaccination and plasma levels of psychotropic agents: a prospective cohort study

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infections induce immunological and inflammatory reactions that may have an impact on cytochrome P450 activity, altering the metabolism of psychotropic drugs. In a cohort study, we prospectively investigated whether SARS-CoV-2 vaccination affects plasma levels of psychotropic agents in association with inflammatory parameter changes. We analyzed data from a cohort of 13 psychiatric inpatients receiving psychotropic treatment who underwent two inoculations of a SARS-CoV-2 mRNA vaccination. Plasma levels of psychotropic drugs and inflammatory markers were measured before and after vaccination. In clozapine-treated patients, plasma levels remained by mean almost constant after both inoculations, although changes were larger in patients without vs. with co-medication with fluvoxamine (p < 0.001 at all timepoints except for timepoint T2; p = 0.9), with minor changes in interleukin 6 (IL-6) and C-reactive protein (CRP). For aripiprazole, quetiapine, olanzapine, lithium, sertraline, escitalopram, duloxetine, and paroxetine, no distinct plasma level patterns at post-vaccination emerged. SARS-CoV-2 vaccination was not associated with essential alterations of psychotropic drug levels. Observed CRP increases did not reach concentrations that may be associated with elevated drug levels. Nevertheless, monitoring of CRP and drug levels is recommended to capture post-vaccine plasma level changes, particularly in patients receiving clozapine.