The Controlled Substances Act regulates:

While the CSA does impact the prescribing of Ativan, it does not directly regulate which patients can receive prescriptions for this medication. Instead, Ativan's classification under the CSA means that practitioners must adhere to certain guidelines and limitations when prescribing it, but the Act does not determine patient eligibility.

The CSA does not regulate pseudoephedrine in terms of requiring a prescription; instead, it is governed by the Combat Methamphetamine Epidemic Act, which imposes restrictions on its sale and purchase to prevent its use in the production of methamphetamine. Thus, this option is incorrect as it does not fall under the CSA's jurisdiction.

Isotretinoin is subject to regulation due to its teratogenic effects, but the CSA does not specifically govern its prescribing and dispensing. Instead, isotretinoin is regulated under the Risk Evaluation and Mitigation Strategy (REMS) program, which is separate from the provisions of the CSA. Therefore, while isotretinoin is controlled, it is not directly regulated by the CSA.