ally if one is "detained" that person is "arrested." Someone is arrested if they are not free to leave. The law requires that a person be brought promptly before a judge if detained. However what "promptly" means varies from jurisdiction to jurisdiction.
If arrested, the person can be held until the court is satisfied that the person will return to court to answer the charges. The severity of the crime is only one factor the court will consider when setting conditions for release. Other factors include the person's ties to the community and any history of previous releases.
THESE COMMENTS ARE NOT LEGAL ADVICE. They are provided for informational purposes only. Actual legal advice can only be provided after consultation by an attorney licensed in your jurisdiction. Answering this question does not create an attorney-client relationship or otherwise require further consultation.
If I understand your question, someone was arrested for possession of a dangerous/prescription drug without a valid prescription. That could be charged as a class 4 felony and could result in being detained for the next 3.75 years. If your question is about the process, the arrested person would be brought before a judge within 24 hours of the arrest. The judge will decide release issues. Detention is up to a police officer making the arrest. Detention is usually just long enough to either arrest someone or issue a citation. Sometimes they allow the person to be released pending lab results and further investigation. You should consider retaining counsel to assist in the defense.
I don't practice in AZ. The difference between detained and arrested for constitutional purposes is someone is detained if they are not free to leave; someone is arrested if the police have determined there is probable cause that a crime was committed and they're the ones who done it. The difference is a formal declaration of arrest. In most circumstances, one can only be held for 72 hours before you must be arraigned or released. If arraigned and bail set, the person can be held until bail is paid, the case goes to trial or they plead out.