Which of the following is a PG3 substance?

• A. Phenobarbital
• B. LSD
• C. Fentanyl
• D. NBOMe

Answer: (A)

PG3 substances are drugs that have legitimate medical use but carry a notable potential for abuse and dependence, so they are regulated to balance medical benefits with safety concerns. Phenobarbital fits this profile as a long-standing, medically approved barbiturate used to treat seizures and for sedation. It has accepted medical use but requires careful prescribing and monitoring because of its dependence potential and risks, which places it in the PG3 category in this framework.

LSD and NBOMe are generally regarded as having no accepted medical use and are tightly controlled or illegal in most systems, so they do not fall into PG3. Fentanyl, while medically useful, is regulated at a higher level due to its extreme potency and high abuse and overdose risk, and is typically placed in a higher-risk category than PG3.