Above is an UpSet plot (similar to a Venn Diagram but with numbers) showing all samples positive for xylazine over the course of this study. So far, xylazine always co-occurs with fentanyl and its associated compounds, tentatively suggesting xylazine is an adulterant of illicitly manufactured fentanyl in San Francisco. This fits with national trends, where xylazine has been added to the opioid supply but not to other classes of drugs.

Above is an UpSet plot similar to the ‘Co-occurring Substances with Xylazine in Xylazine-Positive Samples’ plot but with intersections of frequency greater than 1 occurrence. Listed compounds that are not matched to an intersection (e.g. Non-FDA Approved Benzodiazepines) were only observed to occur once with other compounds.

Above is an UpSet plot of co-occurring substances with xylazine in xylazine-positive samples collected in the past 6 months.

Above is an UpSet plot of co-occurring substances detected in the comprehensive drug screening from samples collected from March 2025 to today. Listed compounds that are not part of any displayed intersection (e.g. Doxylamine) were only observed to occur once with other compounds. This plot will be completed in August 2025.

Above is an UpSet plot of co-occurring substances detected in the comprehensive drug screening from samples collected from September 2024 to February 2025. Intersections with a frequency of 1 are not displayed to improve readability of the plot. Listed compounds that are not part of any displayed intersection (e.g. Methylphenidate) were only observed to occur once with other compounds.

Above is an UpSet plot of co-occurring substances detected in the comprehensive drug screening from samples collected from March to August 2024. Intersections with a frequency of 1 are not displayed to improve readability of the plot. Listed compounds that are not part of any displayed intersection (e.g. Glipizide) were only observed to occur once with other compounds.

Above is an Upset plot of co-occurring substances detected in the comprehensive drug screening from samples collected from September 2023 to February 2024. Intersections with a frequency of 1 are not displayed to improve readability of the plot. Listed compounds that are not part of any displayed intersection (e.g. Non-FDA Approved Benzodiazepines) were only observed to occur once with other compounds.

Above is an Upset plot of co-occurring substances detected in the comprehensive drug screening from samples collected from March to August 2023 (the first 6 months of the study). Intersections with a frequency of 1 are not displayed to improve readability of the plot. Listed compounds that are not part of any displayed intersection (e.g. 4-Hydroxy-Xylazine) were only observed to occur once with other compounds.

Above is an UpSet plot (similar to a Venn Diagram but with numbers) showing all samples positive for fentanyl analogs over the course of this study.

Above is an UpSet plot of co-occurring fentanyl analogs. Intersections with a frequency of 1 are not displayed to improve readability of the plot. Listed compounds that are not part of any displayed intersection (e.g. Norcarfentanil) were only observed to occur once with other compounds.

Above is an UpSet plot of co-occurring fentanyl analogs in samples collected in the past 6 months.