Abuse liability assessment of hydrocodone under current draft regulatory guidelines

Area of Science:

• Pharmacology
• Neuroscience
• Drug Abuse Research

Background:

• Assessing the abuse potential of hydrocodone is crucial for regulatory and clinical practice.
• Guidelines from EMA, ICH, and FDA provide a framework for non-clinical dependence evaluations.
• Understanding hydrocodone's dependence liability informs its controlled substance scheduling.

Purpose of the Study:

• To evaluate the abuse liability and dependence potential of hydrocodone in preclinical models.
• To compare hydrocodone's abuse liability to established opiates, morphine and oxycodone.
• To inform regulatory decisions regarding hydrocodone's classification.

Main Methods:

• Conducted self-administration studies in male Sprague-Dawley rats.
• Utilized drug discrimination assays to assess subjective effects.
• Performed repeat-dose (two-week) dependence liability studies.

Main Results:

• Hydrocodone was readily self-administered by rats.
• It produced subjective discriminative effects similar to other opiates.
• Abrupt cessation led to a significant discontinuation syndrome comparable to morphine and oxycodone.

Conclusions:

• Hydrocodone demonstrates a significant abuse liability.
• Its dependence potential is more aligned with Schedule II opiates.
• Findings support a re-evaluation of hydrocodone's classification under the Controlled Substance Act.