Sweet treats or suspicious results? Navigating poppy seeds in drug testing

Chronic pain management programs use urine drug testing (UDT) to monitor patient compliance and ensure safety when long-term opioids are prescribed. These tests are not punitive but serve to enhance patient safety. Misinterpretation of UDT results can lead to the unjust discontinuation of essential treatment, making accurate interpretation crucial, especially when considering potential interferences like opioid-containing foods.

Poppy seeds from the opium-producing poppy, Papaver somniferum L., are common in food products. While the seeds themselves do not contain opiates, they can be contaminated with poppy latex during harvesting, which contains alkaloids such as morphine and codeine. This contamination can result in detectable opioid levels in urine after consuming poppy seed-containing foods. The alkaloid concentrations can vary significantly based on the geographical location of the poppy growth and the methods used to wash and process the seeds [1]. After ingestion of poppy seeds, these codeine, morphine, and other alkaloids can be found in a subject's urine, hair, and oral fluid.

Several studies from the late 1980s and 1990s examined morphine and codeine exposure from poppy seed ingestion. These studies generally found higher ratios of morphine to codeine in individuals who consumed poppy seed products[1]. Guidelines suggested that urinary codeine concentrations exceeding 300 ng/mL, combined with a morphine-to-codeine ratio of less than 2, indicated codeine use rather than poppy seed ingestion[2]. However, recent studies have observed higher concentrations of codeine compared to morphine [3].

A recent study evaluated various poppy seed food products, such as a poppy seed muffin, a pastry roll with mohn paste (poppy seed filling), and a poppy seed bagel [4]. Results showed that codeine concentrations varied depending on the food product. Those who consumed a poppy muffin or a pastry roll with poppy seed paste exhibited significantly higher codeine concentrations at 3 and 6 hours post-ingestion, with levels ranging from 64 to 1,098 ng/mL for codeine and 1,241 to 37,632 ng/mL for codeine-6-glucuronide [4].

Laboratories can mitigate the impact of poppy seed ingestion on UDT results through several strategies:

1. Patient Education and Specimen Retesting: Educate patients about avoiding poppy seed foods before UDTs and request a second specimen if poppy seed ingestion is suspected, advising patients to abstain for at least a week. However, this method can be challenging for patients with limited ability to return for additional visits or provide more specimens.
2. Monitoring Codeine and Morphine Concentrations: Establish cutoffs to distinguish poppy seed ingestion, although these ratios are not well-established. Recognize that UDT is influenced by various factors and does not directly indicate the timing of exposure or differentiate between poppy seed ingestion, prescription medications, or illicit drugs.
3. Thebaine Monitoring: Some laboratories monitor thebaine levels, a unique compound to poppy seeds, to differentiate poppy seed consumption from morphine derivatives or codeine [5]. This additional measure can provide more accurate interpretation of UDT results, helping ensure that patients receive appropriate management for their chronic pain without undue consequences from misinterpreted tests.

References

1. Lewis J, De Monnin K, Smith J, Lewis E, Wilson M. Interpreting Urine Drug Test Results in the Context of Chronic Opioid Analgesic Therapy and Poppy Seed Consumption. Pain Med. 2021 Nov 26;22(11):2776-2778. doi: 10.1093/pm/pnab082. PMID: 33710300.
2. Tenore PL. Advanced urine toxicology testing. Journal of Addictive Diseases. 2010;29:436–448. doi: 10.1080/10550887.2010.509277.
3. Reisfield GM, Teitelbaum SA, Jones JT. Poppy Seed Consumption May Be Associated with Codeine-Only Urine Drug Test Results. Journal of Analytical Toxicology. 2023;47(2):107–113. doi: 10.1093/jat/bkac079.
4. Wilson RJ, Laha TJ, Baird GS, Hoofnagle AN, Liao HC. Pastry precautions: Poppy seed-containing products cause significant positive results in urine drug tests. Journal of Analytical Toxicology. 2023;47(7):644–645. doi: 10.1093/jat/bkad054.
5. Cassella G, Wu AH, Shaw BR, Hill DW. The Analysis of Thebaine in Urine for the Detection of Poppy Seed Consumption. Journal of Analytical Toxicology. 1997;21(5):376–383. doi: 10.1093/jat/21.5.376.