People are absolutely monitoring when a doctor prescribes tons of opiods. The State of California runs a PDMP (prescription drug monitoring program) known as CURES (Controlled Substance Utilization Review and Evaluation System) [0]. It's a database that records detailed information on all Schedule II, III, and IV prescriptions dispensed in California. Though they don't always check, it's accessible to all doctors and pharmacists. Patients can and do get flags on their accounts, (though as I mentioned, doctors and pharmacists will sometimes ignore them). The DEA is very much in the loop. Anecdotally, they seem to be more concerned with doctors (visiting offices to review records) than individual patients.