Butonitazene is a benzimidazole derivative with opioid effects, which has been sold over the internet as a designer drug. It has relatively low potency compared to many related compounds, and has generally been encountered as a component of mixtures with other substances rather than in its pure form.
The compounds of every Wikipedia article carrying a Chembox or a Drugbox, refreshed daily, with the values their infoboxes give. The pages need JavaScript; the API does not.