U-49900
Limited data
Limited data
Sparse data. Doses and effects may be unreliable or untested.
- 2 corroborating sources
- no dose data
- 29 combo interactions documented
- classified Tentative
- classified Research-chemical
- 2 corroborating sources
- no dose data
- 29 combo interactions documented
- classified Tentative
- classified Research-chemical
Summary
A synthetic opioid sold as an analogue of U-47700, though it shares little of its profile. TripSit staff have pointed readers to a user write-up of an unpleasant and unpredictable experience with it: https://www.reddit.com/r/researchchemicals/comments/5gbo3e/u49900_experiment_and_warning/. No dose data is established.
Tolerance
No tolerance chart. Our decay curves for opioids were estimates, and a curve can make tolerance look longer-lasting than it is, which is the dangerous direction.
Opioid tolerance drops fast when you stop, and even a few days off can be enough, so a dose that used to be normal can now stop your breathing. Overdose deaths rise sharply after prison, detox or leaving treatment, and tolerance also falls during a hospital stay. After any break, start with a much smaller amount, try a test dose first, don't use alone, and keep naloxone within reach. Alcohol, benzodiazepines, gabapentinoids and other sedatives make an opioid overdose much more likely.
Sources: FRANK: heroin · National Harm Reduction Coalition · WHO: opioid overdose · Merrall et al. 2010 · Binswanger et al. 2007 · Strang et al. 2003 · FDA 2019: gabapentinoids and breathing
Combinations
Cross-Check U-49900 with another substanceHelpful Links
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