Counterfeit Norco containing fentanyl and the synthetic opioid U-47700

July 28, 2016, 6:30 pm


Fentanyl and a Novel Synthetic Opioid U-47700 Masquerading as Street “Norco” in Central California: A Case Report. Armenian P et al. Ann Emerg Med 2016 [Epub ahead of print]

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In a recent “Toxicology Rounds” column for Emergency Medicine News, I pointed out that designer opioids such as U-47700 are being identified in street drug specimens and overdose cases with increasing frequency. Knowing this, I was not really surprised when it was announced last week that the autopsy on music superstar Prince confirmed the presence of U-47700, as well as fentanyl.

U-47700 is a synthetic opioid analgesic developed by Upjohn almost half a century ago but never marketed. It is reported to be approximately 7-8 times a potent as morphine. There is at least one case reported in the literature describing a fatality associated with exposure to U-47700 and fentanyl.

This case report, from UCSF-Fresno,  describes a laboratory-confirmed case of overdose following ingestion of illicitly purchased pills that looked like, and were believed by the victim to be, Norco tablets. The patient had ingested 3 of these pills 90 minutes before presentation.On arrival, the serum fentanyl level was 15.2 ng/ml (therapeutic, 1-2 ng/ml.) The patient was described as minimally responsive on presentation but responded to 0.4 mg naloxone and was discharged 4 hours later.

Several months ago, MMWR reported a series of 7 overdoses in the San Francisco Bay area from counterfeit Norco in the San Francisco-Fresno area. Fentanyl was detected in the serum of all these patients.

We should note that despite the attention paid to a “new” synthetic opioid, U-47700 is much less potent than fentanyl and thus most likely presents less of a threat at this time.



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