As Florida gains success with shutting down “pill mills,” demand for prescription painkillers is shifting to retail pharmacies, The Wall Street Journal reports.

In February, the Drug Enforcement Administration announced sales of oxycodone fell 20 percent last year in Florida. Officials said the drop was mainly due to the closure of some of the state’s biggest pill mills and the arrest of some of the clinics’ operators and doctors. Florida pharmacies and doctors sold about 498 million doses of oxycodone in 2011, compared with a record 622 million doses the previous year.

With the decrease in pill mills, retail pharmacies say they have an influx of customers who used to rely on pain clinics to obtain oxycodone and other prescription opioids, according to the newspaper. Pharmacists must determine whether prescriptions are fake or unnecessary, without any uniform guidelines on how to evaluate them. CVS has revised guidelines for dispensing pain medications, providing tips to pharmacists about when they should be suspicious, the article notes.

In June 2011, Florida Governor Rick Scott signed into law a bill designed to cut down on prescription drug abuse by controlling pill mills in the state. The law authorized the creation of a prescription-drug monitoring database to reduce doctor-shopping by people looking to collect multiple painkiller prescriptions. The legislation also imposed new penalties for physicians who overprescribe medication and imposed stricter rules for operating pharmacies.

Mark Perez of the Florida Department of Law Enforcement, said officials are looking into whether dishonest operators are responsible for the surge in applications for new pharmacies. He adds that a growing number of businesses billed as weight-loss centers or wellness clinics are prescribing painkillers. “The drug trade is a for-profit industry, so they’ll look at other areas they can take advantage of,” he said.