Ohio fentanyl overdose expert witnesses analyze overdose care, toxicology findings, and prescribing practices across emergency, inpatient, and addiction settings. They often come from emergency medicine, medical toxicology, pain management, pharmacy, and forensic pathology. In Ohio, they draw on experience from major systems like Cleveland Clinic and OSU Wexner Medical Center. They evaluate causation, naloxone response, drug interactions, and standard-of-care decisions.