Category: Federal Forum Posters
Case Report: Commonly used medications, such as trazodone and ranitidine, may cross-react with the immunoassays in a urine drug screen (UDS) to yield false-positive results. UDS results play an important role in the management of several patient populations including: prescription diversion, employment qualification, and excluding causes of altered mental status or psychosis. In this case series, two Veterans were found to have UDS results positive for amphetamine in the presence of trazodone and ranitidine. Both Veterans adamantly denied any illicit drug use or use of herbal, supplemental, or over-the-counter medications. Due to the relationship between the provider and patient, it prompted further exploration of the situation. Case one involves a 67-year-old Veteran with a history of recurrent major depressive disorder (MDD), post-traumatic stress disorder (PTSD), and insomnia. The Veteran presented to an outpatient clinic upset about his recent UDS through his employer’s human resource department. A review of the Veteran’s historic UDS results were found to be positive for amphetamine in 2015 and 2016; therefore, a confirmatory UDS was obtained and found to be negative for amphetamine. The Veteran was on ranitidine 300 mg/day and trazodone 400 mg/day, which were initiated in 2001 and 2005, respectively. According to the Veteran and his refill history, ranitidine use was infrequent. A trazodone level was reported to be 971 ng/mL. The Veteran was tapered off trazodone over a four-week timeframe. A repeat UDS was collected one month later resulting in undetectable amphetamine levels. Using the Naranjo scale, ranitidine and trazodone were a doubtful and probable cause, respectively, in regards to the false-positive amphetamine level. Case two involves a 50-year-old Veteran with a history of severe recurrent MDD, PTSD, and shoulder pain who requests a renewal of his opioids. Prior to fulfilling the renewal, the primary care provider requested a UDS, which tested positive for amphetamine. Trazodone and ranitidine were initiated in 2015 and 2018, respectively. The Veteran reported taking trazodone 100-150 mg/day and ranitidine 150 mg/day; however, due to worsening symptoms, he started taking ranitidine 300 mg/day as prescribed in the recent 2-3 weeks. Prior to the most recent UDS, the Veteran had unremarkable UDS results dating back to 2011 and a trazodone level of 947 ng/mL. A confirmatory UDS resulted in negative amphetamine levels. In addition, a repeat UDS was completed six days later, which also tested negative for amphetamine. Using the Naranjo scale, ranitidine and trazodone were possible causes of the false-positive amphetamine level. As this case series suggests, common medications, such as trazodone and ranitidine, may result in false-positive amphetamine levels. Providers should be familiar with these medications and request confirmatory testing when appropriate to prevent disruption of the provider-patient relationship.
Tina Chov– PGY1 Pharmacy Resident, Nebraska-Western Iowa Health Care System, Lincoln, NE