What is DXM + Promethazine? Dextromethorphan (DXM) is a cough suppressant medication in the morphinan class that is widely used in cough and cold medicines. At high doses, DXM can act as a dissociative hallucinogen. Promethazine is a first-generation antihistamine, sedative, and antiemetic medication used to treat allergies, insomnia, and nausea. As a strong anticholinergic, it produces significant sedative effects and can act as a deliriant at toxic doses.

What was found? The NDEWS web monitoring team checked for mentions of saccharin due to a December report from the UNC Street Drug Analysis Lab stating that Saccharin was detected in their drug checking. Saccharin had also seen an increase in online mentions recently. After further investigation, the NDEWS web monitoring team found that one of the contributing factors to the increase in saccharin was an increase in discussion of the combination of dextromethorphan and promethazine, due to the ingredients inclusion as a sweetener in many cough medications that include one of the aforementioned substances. There has been online discussion on combining dextromethorphan and promethazine for at least the past 10 years. There has been a recent spike in activity starting in August of 2024. Discussion of the polysubstance is currently more than double what it was at the beginning of 2024.

How is it being discussed? Online discussions indicate that users are combining DXM and promethazine to enhance the dissociative and sedating effects of both substances. Some comments note that promethazine's antiemetic effects may mask DXM-induced nausea which typically serves as a natural limiting factor for excessive dosing. Reddit users report difficulty in finding appropriate dosages due to variable potentiation effects between individuals. There are numerous reports of delirium, paranoia, and anxiety. Reddit users also note increased risks of falls and injuries due to severely impaired coordination and balance. There are also comments discussing cardiovascular strain and the unknown long-term cognitive effects of regular combined use.

Dextromethorphan Terms: Dextromethorphan, DXM, Robitussin
Promethazine Terms: Promethazine, Phenargan

Click here to read more about NDEWS Online Monitoring.

A recent JAMA Network Open study assessed over-the-counter (OTC) naloxone and nonprescription syringe availability in 125 community pharmacies in Austin, Texas (100% response rate). OTC naloxone was found in 55.2% of pharmacies, with 36.0% having at least one box in stock. Branded naloxone was more available than generic ($44.99 vs. $39.99 median cost). Syringe purchase attempts were successful 58.4% of the time, with a median cost of $3.19. However, 88.5% of denials required proof of a prescribed injectable medication. Only 20.0% of pharmacies had both naloxone on shelves and sold syringes.

Read more here.

A recent Journal of Medical Toxicology scoping review examined naloxone dosing and hospitalization for nitazene overdoses, analyzing 19 cases across four nitazene compounds. Median naloxone doses varied significantly: metonitazene required the highest (6.00 mg), followed by etonitazene (3.06 mg), isotonitazene (3.00 mg), and protonitazene (1.00 mg). Hospitalization rates were high, with mean length of stay ranging from 20 hours (protonitazene) to 360 hours (metonitazene). Naloxone reversed 82% of cases, but most required multiple doses.

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A recent analysis in the Journal of Analytical Toxicology by NDEWS Co-I Dr. Bruce A. Goldberger, NDEWS SAG member Dr. Barry K. Logan, and NDEWS collaborator Dr. Alex J. Krotulski analyzed 125 forensic cases involving N,N-dimethylpentylone (DMP), a potent synthetic cathinone. DMP blood concentrations ranged from 3.3 to 4600 ng/mL (median: 150 ng/mL), with its metabolite pentylone detected in 98% of cases. Using liquid chromatography–tandem mass spectrometry (LC-MS/MS), researchers confirmed DMP’s high potency at dopamine transporters (IC50 = 49 nM) and stimulant effects in mice (ED50 = 3.5 mg/kg). The analysis highlights DMP’s role in fatal overdoses and warns of emerging synthetic stimulants following its 2024 scheduling.

Read more here.

A recent report from Millennium Health highlights an alarming increase in the co-occurrence of stimulants such as methamphetamine and cocaine. The analysis draws from over 1.4 million fentanyl-positive urine drug tests from patients diagnosed with substance use disorders across the U.S., covering shifts in drug use patterns from 2016 to 2024.

Read more here.

The HALT Fentanyl Act passed the U.S. House of Representatives in a 312-108 vote, classifying all fentanyl-related substances as Schedule I drugs. Supporters argue it strengthens enforcement against fentanyl analogues, while critics warn it could increase incarceration and deter overdose reporting. The bill also streamlines research on Schedule I substances like marijuana and psychedelics by requiring the DEA to process applications within 30-45 days, eliminating duplicate registrations, and allowing limited drug manufacturing for research—excluding cannabis. An amendment to delay enactment until federal agencies confirmed overdose reduction was rejected. Another, which could have impacted marijuana rescheduling, was withdrawn. The U.S. Senate will now consider the bill.

Read more here.

A recent Psychology Today: Addiction Outlook article by Mark Gold, M.D., examines medical marijuana’s role in chronic pain. While 38 states have legalized it, bypassing FDA oversight, research on its effectiveness remains mixed. Harvard’s Kevin Hill, M.D., urges prioritizing FDA-approved treatments like Journavx (suzetrigine) over cannabis, which lacks standardized dosing. The FDA requires more research before approval, though Yale’s cannabigerol (CBG) study shows promise for non-addictive pain relief. As laws shift, balancing access with safety remains key. 

Read more here.

📅 Date: February 26, 2025

⏰ Time: 2:30 pm to 3:30 pm ET

📍 Location: Virtual

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📅 Dates: May 29 - May 30, 2025

🗓️ Submission deadline: February 19, 2025

📍Location: UF Academic and Research Center at Lake Nona, Orlando, FL

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📅 Dates: June 2 - 4, 2025

🗓️ Submission deadline: March 1, 2025

📍 Location: University of Puget Sound, Tacoma, WA

Learn more here.

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If you miss or want to learn more about NDEWS Original Content, you can find our archived content on the NDEWS website:

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     • NDEWS Rapid Street Reporting (RSR) survey data reports
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The Weekly Briefing is a newsletter published each week by the National Drug Early Warning System (NDEWS) Coordinating Center, which is funded by the National Institute on Drug Abuse (U01DA051126) to the University of Florida (PI: Cottler, Co-Is: Goldberger, Nixon, Striley), New York University (Deputy Director: Palamar), and Florida Atlantic University (Co-I: Barenholtz). Any item may be reproduced provided the source is acknowledged.