Access to rogue online pharmacies may be driving a rapid increase in the abuse in the United States of prescription drugs like powerful painkillers Percocet and Oxycontin, a new study shows.

The pharmacies, typically located outside the United States, send out millions of email solicitations a year, and many do not adhere to U.S. regulations requiring a physician’s prescription for the drugs.

Investigators from Massachusetts General Hospital and the University of Southern California found that, over a seven-year period, states with the greatest expansion in high-speed Internet access also had the largest increase in admissions for treatment of prescription drug abuse.

The findings were released on Thursday by the journal Health Affairs, and will appear in its June edition.

“Our findings suggest that Internet growth may partly explain the increase in prescription drug abuse, since it is well known that these drugs are easily available online,” said Dana Goldman, director of the Schaeffer Center for Health Policy and Economics at the University of Southern California.

Prescription drugs are fast replacing illegal substances in venues like college campuses, Goldman said.

Goldman and Anupam Jena, of the MGH Department of Medicine, note that the recent marked rise in the abuse of prescription narcotic painkillers corresponds with an increase in the presence of online pharmacies.

Drugs that are frequently abused - painkillers, sedatives, stimulants, and tranquilizers - often can be purchased from rogue sites located outside the United States.

The researchers paired data available on Internet access from the Federal Communications Commission with figures on admissions to substance abuse treatment facilities.

Changes in both measures from 2000 to 2007 were analyzed on a per-state basis, and treatment admissions were categorized by the types of abused substances involved.

Each 10-percent increase in the availability of high-speed Internet service in a state was correlated with a roughly one-percent increase in admissions for prescription drug abuse, the researchers found.

During the same period admissions to treat abuse of heroin or cocaine, drugs not available over the Internet, and alcohol either rose minimally or actually fell.

“The lack of an increase in abuse of drugs not available on the Internet suggests that an overall growth in drug-seeking behavior cannot explain the rise in prescription drug abuse,” Jena said.

The U.S. Pharmacy Consumer Protection Act, which went into effect in 2009, prohibits delivery of controlled substances not prescribed by a physician. The U.S. Food and Drug Administration has issued warnings to more than 100 online pharmacies for violations. The impact of the FDA’s measures is currently unknown, said Jena.

SOURCE: Health Affairs, online May 12, 2011.