Quetiapine and False-Positive Urine Drug Testing for Tricyclic Antidepressants

Sloan, Kevin L.; Haver, Virginia M.; Saxon, Andrew J.

doi:10.1176/ajp.157.1.148-a

Cited by 28 publications

(17 citation statements)

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“…Cetirizine was previously identified as cross-reacting with fluorescence polarization immunoassays (30). Quetiapine was previously identified as cross-reacting with some marketed TCA screening immunoassays (7-9). …”

Section: Resultsmentioning

confidence: 99%

“…Examples of published reports of DOA/Tox assay cross-reactivity include fluoroquinolone antibiotic cross-reactivity with opiates assays (5, 6), quetiapine cross-reactivity with tricyclic antidepressant (TCA) assays (7-9), fentanyl cross-reactivity with LSD immunoassays (10, 11), sertraline and sertraline metabolite cross-reactivity with benzodiazepine assays (12, 13), and venlafaxine and O -desmethylvenlafaxine cross-reactivity with PCP assays (14). …”

Section: Introductionmentioning

confidence: 99%

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Chemoinformatic Methods for Predicting Interference in Drug of Abuse/Toxicology Immunoassays

et al. 2009

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chemoinformatic Methods for Predicting Interference in Drug of Abuse/Toxicology Immunoassays

et al. 2009

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“…Interestingly, another antipsychotic drug, olanzapine showed only minimal crossreactivity (0.06%-0.7%) and did not interfere with the immunoassay used for TCA. 38 Cerullo et al commented that 5 patients who initially tested negative for TCAs tested positive after being treated with topiramate or quetiapine. A quetiapine trough blood level was obtained at the same time when urine toxicology screen of TCA was performed, and the results paralleled positive urinary TCA screen (when patients showed serum quetiapine levels between 5.1 and 85 ng/mL, urine TCA was also positive).…”

Section: Issues Of Interferences With Immunoassays For Tricyclic Antimentioning

confidence: 99%

Impact of Interferences Including Metabolite Crossreactivity on Therapeutic Drug Monitoring Results

Dasgupta¹

2012

Therapeutic Drug Monitoring

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Therapeutic drug monitoring is an integral part of services offered by toxicology laboratories because certain drugs require routine monitoring for dosage adjustment to achieve optimal therapeutic response and avoid adverse drug reactions. Immunoassays are widely used for therapeutic drug monitoring. However, immunoassays suffer from interferences from both exogenous and endogenous compounds including metabolites of the parent drug. Digoxin immunoassays are affected more commonly than any other immunoassays used for therapeutic drug monitoring. Digoxin immunoassays are affected by endogenous digoxin-like immunoreactive substances and exogenous compounds such as various drugs, certain herbal supplements, and Digibind. Carbamazepine is metabolized to carbamazepine 10, 11-epoxide, and the crossreactivity of this metabolite with carbamazepine immunoassay may vary from 0% to 94%. Immunoassays used for measuring concentrations of tricyclic antidepressants are affected by tricyclic antidepressant metabolites and by a number of other drugs. Immunoassays for immunosuppressants are also subjected to significant interferences from metabolites, and liquid chromatography combined with mass spectrometry or tandem mass spectrometry is recommended for therapeutic drug monitoring of immunosuppressants. However, liquid chromatography combined with mass spectrometry may also suffer from interferences, for example, due to ion suppression or from isobaric ions.

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“…The structure of quetiapine is similar to that of TCAs (both contain a similar tricylcic framework), and there have been two prior case reports in the literature that noted false positives for TCAs in adult patients taking quetiapine (1,2). Three in vitro studies (1–3) found false positive TCA results in some immunoassays using concentrations as low as 160 ng/ml of quetiapine.…”

mentioning

confidence: 99%

“…Three in vitro studies (1–3) found false positive TCA results in some immunoassays using concentrations as low as 160 ng/ml of quetiapine. To our knowledge, there have been no prior reports of cannabis or topiramate causing false positives for TCAs.…”

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confidence: 99%

Tricyclic Antidepressant Immunoassays May Reflect Quetiapine Adherence

Cerullo¹,

Albertz²,

Bell³

et al. 2008

AJP

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As part of an ongoing treatment study of co-occurring bipolar mania and cannabis abuse in adolescents, we obtained bi-monthly urine toxicology screens using the Status DS™ immunoassay. It was noted that the first five subjects initially tested negative for tricylcic antidepressants (TCAs) but all five tested positive after being treated with topiramate or placebo and quetiapine. All of the patients denied using TCAs, but were forthcoming regarding their drug use. A quetiapine trough blood level was also obtained on the same morning that the urine toxicology screens were performed and the results paralleled the TCA toxicology findings, i.e., when subjects showed quetiapine in their serum (5.1 to 85 ng/ml), they tested positive for TCAs. However, when two of the subjects were non-adherent to their medications and their quetiapine levels were undetectable, their toxicology screens were negative for TCAs. After these two patients were encouraged to take their medications and had detectable quetiapine levels, they once again tested positive for TCAs.The structure of quetiapine is similar to that of TCAs (both contain a similar tricylcic framework), and there have been two prior case reports in the literature that noted false positives for TCAs in adult patients taking quetiapine (1,2). Three in vitro studies (1-3) found false positive TCA results in some immunoassays using concentrations as low as 160 ng/ml of quetiapine. To our knowledge, there have been no prior reports of cannabis or topiramate causing false positives for TCAs. Therefore, we concluded that treatment with quetiapine was causing the positive TCA toxicology screens in our subjects, which occurred even at levels close to the detection threshold (as low as 5.1 ng/ml). Doses of quetiapine ranged from 300 to 600 mg and there was high variability in serum level between subjects for a specific dose of quetiapine. These data are consistent with prior research which reported only modest to no correlation between dose and serum concentration with high intersubject variability and no correlation with therapeutic effectiveness (4,5). Adolescents with bipolar disorder are poorly adherent to their medications. Therefore, qualitative measures of quetiapine may be useful to determine whether patients have been medication adherent. Our findings suggest that certain immunoassays for TCAs are useful as a qualitative test for quetiapine adherence and may avoid the need for more expensive serum levels. Regardless, physicians should be aware of this potential cross-reactivity in patients taking quetiapine.

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Quetiapine and False-Positive Urine Drug Testing for Tricyclic Antidepressants

Abstract: provides important insight into the real cost of the treatment of depression for patients, rather than the cost assumed by third-party payers. The authors suggest that the reason for the cost savings for patients treated by psychiatric specialists

Cited by 28 publications

References 1 publication

Chemoinformatic Methods for Predicting Interference in Drug of Abuse/Toxicology Immunoassays

Chemoinformatic Methods for Predicting Interference in Drug of Abuse/Toxicology Immunoassays

Impact of Interferences Including Metabolite Crossreactivity on Therapeutic Drug Monitoring Results

Tricyclic Antidepressant Immunoassays May Reflect Quetiapine Adherence

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