PDE4A and alcohol abuse: Supporting the translational potential of PDE4 inhibitors for treating substance use disorders, the non-selective PDE4 inhibitor ibudilast has advanced to Phase II clinical trials for MA use disorder (ClinicalTrials.gov (accessed on 13 February 2021) identifier: NCT01860807) and for oxycodone misuse (NCT01740414) and is currently in Phase 1 clinical trials for alcohol use disorder (NCT02025998) [35] with recent reports indicating efficacy and safety [36,37,38,39,40,41,42].