(HAP) of many formulations. These concerns, along with regulatory–authority directives, have led to the development of opioid formulations expected to have abuse-deterrent properties. The attractiveness of opioids for abuse have been quantified using validated measures of subjective pharmacodynamic (PD) effects (e.g., drug liking, drug high), as well as select pharmacokinetic (PK) characteristics of opioids, such aspeakplasmaconcentration (Cmax) and time to achieveCmax expressed as tmax. For example, tampering with opioid formulations (e.g., altering themode of administration) may increase PD effects by increasing Cmax and/or shortening tmax. Given this PK relationship, whichmay foster a drug’s attractiveness for abuse, the Cmax/tmax ratio has been called the abuse quotient (AQ). This investigation examined the putative validity of using AQ as a surrogate clinical measure to characterize the HAP of opioid analgesic formulations. Methods: PK and PD data were retrospectively gathered from a series of randomized, double-blind, controlled clinical trials (RCTs) exploring the HAP of proposed abuse-deterrent extended-release opioid formulations in comparison with control opioid formulations with high abuse potential and, in some cases, placebo. Correlations of AQ, Cmax, and tmax with subjective PD effects influencing drug abuse were assessed within and between RCTs. Results: In all instances, there were statistically significant and high correlations of AQ and PD effects, with higher AQ denoting greater abuse potential. Overall, these associations were stronger for AQ than for Cmax or tmax individually. Conclusions: The AQ appears to be an essential parameter of HAP when developing abuse-deterrent opioid formulations. Further analyses using real-world surveillance data for comparison are recommended. Financial support: Funded internally by PRA Health Sciences, Salt Lake City, UT, USA.