Any custodial interrogation of a suspect you have probable cause to believe committed a crime requires reading them their rights. If you don't, their lawyer can get whatever they tell you suppressed in court. The only exception are questions necessary to secure the officers own safety or the safety of the public. Asking questions about dope would not rise to that standard, unless you can reasonably say a small kid might some of their pills if they aren't found.
Any custodial interrogation of a suspect you have probable cause to believe committed a crime requires reading them their rights. If you don't, their lawyer can get whatever they tell you suppressed in court. The only exception are questions necessary to secure the officers own safety or the safety of the public. Asking questions about dope would not rise to that standard, unless you can reasonably say a small kid might some of their pills if they aren't found.