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Dozens of Adulterants Found in San Diego's Fentanyl Supply

The opioid overdose crisis continues to cast a shadow over the United States, and new research suggests that the presence of drug adulterants may exacerbate its impact. A recent study conducted by BMC Public Health delves into the presence of impurities within the local fentanyl supply of San Diego County.

The findings, drawn from information provided by 22 local law enforcement agencies, shed light on the hidden dangers lurking within illicit drug samples seized in 2021.

Methods: Peering into the Shadows

The study, encompassing data from 4838 unknown illicit drug samples, relied on a collaborative effort involving various agencies across San Diego. Researchers used advanced analytical techniques to identify and analyze the composition of seized substances.

Fentanyl Adulterants Yielded Surprising Findings

The results of the analysis unveiled a troubling reality. Among the substances identified, methamphetamine emerged as the most prevalent (38.7%), followed by diacetylmorphine (heroin) (10.2%), codeine (5.8%), and alprazolam (4.3%).

Perhaps even more concerning was the fact that authorities found 52 unique adulterants within the fentanyl samples. These included substances like 4-methylaminoantipyrine (4-MAAP), mannitol, acetaminophen, tramadol, and xylazine, among others.

Implications and Concerns For Public Health

The implications of these findings for public health and harm reduction efforts are profound. The presence of potentially harmful adulterants underscores the urgent need for ongoing surveillance of the drug supply. The emergence of substances like xylazine, known for its association with overdose incidents, raises a public health alarm.

Which Adulterants Are In The Fentanyl Supply?

Here's the list of adulterants categorized by the type of drug they were found with:


  • Methamphetamine (38.7%) - highest percentage


  • Diacetylmorphine (Heroin) (10.2%)
  • Morphine
  • 6-Monoacetylmorphine
  • Oxycodone
  • Codeine
  • Methadone
  • Fluonitazene
  • Protonitazene
  • Isotonitazene

Benzodiazepines and Sedatives:

  • Alprazolam (4.3%)
  • Diazepam
  • Clonazepam
  • Phenobarbital
  • Etizolam
  • Carisoprodol

Other Pharmaceutical Compounds:

  • Acetaminophen
  • Dextromethorphan
  • Lidocaine
  • Cocaine
  • Procaine
  • Caffeine
  • Delta 9-tetrahydrocannabinol
  • Bupivacaine

Adulterants and Contaminants:

  • 4-methylamino antipyrine (4-MAAP)
  • Mannitol
  • Tramadol
  • Xylazine
  • Fluorofentanyl
  • Acetyl fentanyl
  • Benzylfentanyl
  • Methyl acetyl fentanyl
  • Levamisole
  • Etizolam
  • Sorbitol
  • 4-aniline-N-phenethylpiperidine (4-ANPP)
  • Phenethyl 4-ANPP
  • 1-hexadecanol
  • 1-hexadecene

This breakdown provides insight into the various types of drugs found in the illicit markets, along with the adulterants associated with each type. Many of these drugs can cause effects that are dangerous to drug users.

For example, Levamisole, an anti-parasitic drug, has been reported to have stimulant effects similar to cocaine, albeit to a lesser degree. It's also less expensive than cocaine and can be added to increase the overall weight of the product. However, it's also a dangerous drug. Levamisole can cause skin reactions such as rash or lesions, particularly when used chronically or in high doses. It can decrease the production of white blood cells, essential for fighting infections. This condition can lead to a weakened immune system and increase the risk of infections.

All drugs have side effects, and some of them can be life-changing.

Looking Forward: Fighting the Opioid Epidemic

People who use fentanyl are people who also live with fentanyl use disorder. They may know the risks of pollutants, but few people understand what contaminants are in the drugs or how they could hurt a user.

Xylazine, designed initially as a veterinary sedative, is an increasingly popular adulterant that is also highly addictive. Many users in California have lost limbs or been hospitalized from the lesions it causes.

While the study provides valuable insights into the composition of illicit drug supplies in the region, it also underscores the need for further research. Understanding the impact of these adulterants on drug use and associated risks remains a critical area for exploration.

The findings of this study serve as a somber reminder of the challenges posed by the opioid crisis. Communities can proactively address this ongoing public health challenge by remaining vigilant and informed.

Making treatment available, counseling, medication-assisted treatment, and other vital public health services can help minimize damages.

There is always hope that a person who uses fentanyl will be able to get sober and find recovery.

Getting Help for Opioid Use Disorder

At Present Moments Recovery, we don't just address opioid use disorder; we offer hope, compassion, and the opportunity for a brighter, drug-free future. Get in touch to learn more about our programs and how we can help you reclaim your life.



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