False-positive fentanyl screening kit results during treatment with long term injectable risperidone...

Area of Science:

• Clinical Toxicology
• Psychopharmacology
• Forensic Science

Background:

• Fentanyl is a potent synthetic opioid linked to numerous overdose deaths globally.
• Urine drug immunoassays are standard for fentanyl screening but can yield false positives.
• Accurate fentanyl detection is critical for patient care and public health.

Purpose of the Study:

• To report cases of false positive fentanyl screening in patients receiving specific treatment.
• To investigate potential drug interactions affecting urine drug test accuracy.
• To raise awareness of potential inaccuracies in fentanyl screening.

Main Methods:

• Case series report of three patients.
• Patients had a diagnosis of schizophrenia.
• Treatment involved long-term injectable risperidone.
• Screening utilized a rapid commercial immunoassay kit for fentanyl.

Main Results:

• All three patients, treated with injectable risperidone, showed false positive results for fentanyl.
• No actual fentanyl use was confirmed in these patients.
• The screening kit indicated the presence of fentanyl when it was not misused.

Conclusions:

• Long-term injectable risperidone may lead to false positive fentanyl urine drug screening results.
• Clinical settings must consider the possibility of inaccurate fentanyl test outcomes.
• Further investigation is warranted to understand this phenomenon and its implications.