The "Stopping Overdoses of Fentanyl Analogues Act" classifies fentanyl-related substances as Schedule I drugs under the Controlled Substances Act, making them subject to the strictest controls and penalties. This classification applies to any substance structurally related to fentanyl with specific chemical modifications, unless explicitly exempted or listed in another schedule. The goal of this act is to combat the proliferation of dangerous fentanyl analogues and reduce overdose deaths. It goes into effect one day after it is enacted.