Quetiapine Carboxylic Acid and Quetiapine Sulfoxide Prevalence in Patient Urine

Abstract

Treatment adherence is often an issue with mental health patients. For those prescribed quetiapine (Seroquel), the low levels of parent drug and plasma metabolite(s) (e.g., 7-hydroxyquetiapine) typically used in urine drug monitoring can result in false negatives with concomitant unfavorable impacts on patient care. Literature review coupled with liquid chromatography/time-of-flight mass spectrometry analysis of patient positive urine samples indicated the presence of quetiapine carboxylic acid and quetiapine sulfoxide as significant urinary metabolites of quetiapine. Analysis of these two metabolites determined that they are abundant in the urine of quetiapine patients and can result in apparent adherence rates that are improved relative to those determined using only quetiapine and 7-hydroxyquetiapine. For example, analysis of a random set of 114 patients who were prescribed quetiapine exhibited an apparent adherence rate of 47% using the quetiapine carboxylic acid and quetiapine sulfoxide metabolites. Traditional metabolite testing with quetiapine and 7-hydroxyquetiapine yielded apparent adherence rates of ~31% while all four analytes resulted in apparent adherence of 48%. The prevalence of these metabolites suggests that quetiapine urine drug testing would be more consistent with prescriptions when they are included in the analysis.

In Vitro Drug-Drug Interaction Potential of Sulfoxide and/or Sulfone Metabolites of Albendazole, Triclabendazole , Aldicarb, Methiocarb, Montelukast and Ziprasidone

“…The inclusion of quetiapine sulfoxide measurement in urine along with other analytes improved the adherence from 31% to 48%. Therefore, quetiapine sulfoxide due to its longer residence and larger systemic availability may provide an opportunity for a possible drug-drug interaction [21]. Secondly, in the case of triclabendazole sulfoxide, it was noted that the circulatory concentrations of the metabolite (peak concentration: 38.6 uM) far exceeded the observed concentration of the parent drug triclabendazole (peak concentration: 1.16 uM) following a standard dose of triclabendazole of 10 mg/kg in humans to treat trematode infestations such as Fascioliasis and Paragonimiasis [22].…”

A Comment on the levels of antipsychotics and their metabolites in urine

“…9 Strickland et al 9 reported that both the carboxylic acid and the sulfoxide of QTP were present at very high levels which were unaffected by hydrolysis. 10 Again, the carboxylic acid of QTP is available commercially for these analyses. 11 The impact of choosing a more prevalent metabolite for analysis is clearly demonstrated with the authors' choice of 7-hydroxychlorpromazine (HOCPZ) for analysis of chlorpromazine.…”