Phentermine Schedule Classification
Phentermine is classified as a Schedule IV controlled substance under the Controlled Substances Act. 1
Regulatory Classification Details
Schedule IV designation is based on concerns for potential abuse and dependence, though phentermine has lower abuse potential compared to Schedule II or III substances 2
This classification places phentermine in the same category as other medications with recognized medical use but some potential for abuse 1
Important Clinical Context Regarding Abuse Potential
Actual Abuse Risk vs. Regulatory Classification
Despite its Schedule IV classification, clinical evidence demonstrates minimal actual addiction potential when phentermine is used appropriately for obesity treatment 3, 4
Phentermine is chemically and pharmacologically related to amphetamines, which historically contributed to regulatory concerns about abuse 1
However, research specifically examining long-term phentermine users (up to 21 years of treatment) found no evidence of psychological dependence, drug craving, or amphetamine-like withdrawal symptoms upon abrupt cessation 3, 4
Key Distinction from Amphetamines
While the FDA label notes that amphetamines have been extensively abused and warns about this possibility with phentermine 1, controlled studies show phentermine does not induce the characteristic craving that defines substance dependence 3, 4
Symptoms observed after stopping phentermine represent loss of therapeutic effect (increased hunger) rather than true withdrawal 3
Prescribing Implications of Schedule IV Status
Prescribers must follow DEA regulations for Schedule IV controlled substances, including proper documentation and prescription requirements 2
State-specific regulations may vary regarding prescribing controlled substances, and clinicians should confirm requirements with their respective state licensure authorities 2
The Schedule IV classification may create barriers to access despite the medication's favorable safety profile when used appropriately 2