ABSTRACT: Background:Abuse of prescription opioids, particularly by intravenous (IV) administration, can cause respiratory depression and death. ALO-02, an abuse-deterrent opioid formulation, is designed to release sequestered naltrexone upon manipulation by crushing, thereby antagonizing the pharmacologic effects of oxycodone. This exploratory post-hoc analysis examined the effects of IV administration of simulated crushed ALO-02 on end-tidal carbon dioxide (EtCO2), a surrogate marker of respiratory depression. Methods:Data were obtained from a randomized, double-blind, placebo-controlled, three-way crossover study in nondependent recreational opioid users that evaluated the abuse potential of IV administered oxycodone 20?mg + naltrexone 2.4?mg (simulating crushed ALO-02) versus oxycodone 20?mg or placebo. EtCO2 was measured as a secondary endpoint using noninvasive capnography at baseline and postdose intervals, up to 24?h. Results:Baseline EtCO2 (mean ± standard error of the mean (SEM)) values (n?=?33) were similar across treatments: 33.5?±?0.9, 33.5?±?0.8, and 34.0?±?0.7?mmHg for oxycodone 20?mg + naltrexone 2.4?mg, oxycodone 20?mg, and placebo, respectively. After dosing, mean ± SEM of the maximum effect (Emax) on EtCO2 was 37.5?±?0.6, 40.5?±?0.8, and 36.9?±?0.6?mmHg for oxycodone 20?mg + naltrexone 2.4?mg, oxycodone 20?mg, and placebo, respectively. Emax values were significantly lower for oxycodone 20?mg + naltrexone 2.4?mg versus oxycodone 20?mg (p?=?0.0005), and not different from placebo (p?>?0.05). Conclusions:This abuse-potential study suggests that naltrexone released from ALO-02 tampering by crushing attenuates oxycodone-induced increase of EtCO2 in nondependent recreational opioid users.