Effects of Switching From Smoking to Vaping on Clozapine Concentration-Dose Ratios and Plasma Clozapine Concentrations: A Systematic Review of Case Reports.
Somtochukwu D Uche, Deborah Robson, Hannah Walsh et al.
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From the abstract
Smoking tobacco cigarettes affects the metabolism of several antipsychotic medications by inducing CYP1A2 enzymes. Clozapine is particularly sensitive to this effect, as CYP1A2 induction increases the plasma clearance of the drug, resulting in lower clozapine plasma concentrations and a reduced clozapine concentration-dose (C/D) ratio than that in nonsmokers.
Reported results
Five articles were identified, all case reports describing 5 patients (4 male) who switched from tobacco cigarettes to e-cigarettes while taking clozapine. Switching resulted in increased C/D ratios and plasma clozapine concentrations, although the magnitude of this increase varied among individuals.
Authors' conclusions
Based on the small number of case reports, complete switching from tobacco smoking to e-cigarette vaping may have a similar effect on clozapine plasma concentrations and C/D ratios as smoking cessation without vaping. The authors found no research on the impact of vaping on clozapine concentrations and C/D ratios in people who had never smoked.