A recent analysis by the CDC and published in Morbidity And Mortality Weekly Reports has shown that antihistamines play a role in the growing drug overdose crisis. Of the total US drug overdose deaths reported to the CDC from 2019 to 2020, 13,574 (14.79%) involved antihistamine positivity. First-generation H1 subtype antihistamines, such as diphenhydramine, made up 99.6% of antihistamine-positive and 99.8% of antihistamine-involved deaths. Opioids, often illicit fentanyl, were involved in 82.8% of antihistamine deaths. The authors highlight the importance of continued surveillance to understand the drugs and drug combinations contributing to overdose deaths and to raise awareness about the dangers of co-using substances. They also stated that since the opioid anti-overdose drug naloxone does not work with antihistamines, co-involved opioid and antihistamine overdoses might require additional measures to prevent death. The limitations of the study include a lack of standardized drug testing methods and a limited number of jurisdictions covered.