What is a recognized resource for identifying controlled substances?

The Physician's Desk Reference (PDR) is a renowned resource for identifying controlled substances because it provides comprehensive information on prescription medications, including detailed descriptions, dosages, side effects, and schedules of controlled substances. It is widely used by healthcare professionals, including physicians and pharmacists, to make informed decisions about medication management.

This reference includes both prescription and over-the-counter medications, along with critical information regarding their classification under federal regulations, such as the Controlled Substances Act. In doing so, the PDR enables practitioners to identify controlled substances accurately and understand their potential for abuse or dependence.

The other options, while they may provide useful health information, do not specifically focus on the identification and classification of controlled substances in the manner that the PDR does. Thus, the PDR stands out as the most authoritative and specialized source in this context.