Which drug is noted as not being listed in the Physician's Desk Reference (PDR)?

Heroin is not listed in the Physician's Desk Reference (PDR) because it is classified as a Schedule I controlled substance and is not approved for medical use in the United States. The PDR contains information about medications that are legally prescribed and used in therapeutic contexts. Heroin is primarily recognized for its illicit use and associated risks rather than any medical application, which is why healthcare providers do not reference it in standard medical guides like the PDR.

In contrast, cocaine, alcohol, and marijuana have recognized therapeutic uses or historical medical contexts in the literature, which leads to their inclusion in medical references like the PDR. Cocaine has medical applications as a local anesthetic in specific surgical procedures, alcohol is a common substance with both medicinal and recreational uses, and marijuana, which has gained legal status in many jurisdictions, can be prescribed for certain conditions. These factors distinguish them from heroin in terms of medical documentation and acceptance.