The "smokeless cigarette" being test marketed by R.J. Reynolds could be modified by drug users to smoke crack, a form of cocaine, a study published Thursday said.

Addicts could smoke crack inconspicuously in public by replacing with cocaine the elements containing nicotine in Premier cigarettes, Edward Cone and Jack Henningfield of the National Institute on Drug Abuse wrote in the Journal of the American Medical Association.In the patent application for Premier "smokeless cigarettes," which work by drawing air heated by a burning charcoal tip through a chamber containing nicotine and tobacco flavoring, Reynolds said the device could be used to deliver other pharmaceutical drugs, the authors noted.

The study employed smoking machines that showed the cigarettes could be easily modified to deliver crack, a widely abused drug that law enforcement officials have tied to a rising murder rate in some cities.