Updated

Justin Knox bit down on the bitter-tasting patch, instantly releasing three days' worth of a drug more powerful than morphine. He was dead before he even got to the hospital.

The 22-year-old construction worker and addict was another victim in an apparent surge in U.S. overdoses blamed on abuse of the fentanyl patch, a prescription-only product that is intended for cancer patients and others with chronic pain and is designed to dispense the medicine slowly through the skin.

"I cannot tell you the amount of people I've seen and the creative ways they abuse this drug," said Dr. Scott Teitelbaum, director of the Florida Recovery Center in Gainesville, Fla. "Fentanyl has been abused for years. But recently there has been an increase. I've seen more chewing, squeezing of the drug off the patch and shooting it up."

Fentanyl, a synthetic narcotic, was introduced in the 1960s, but it was not until the early 1990s that it became available in patch form. Last year, the first generic versions of the patch hit the market.

At least seven deaths in Indiana and four in South Carolina since 2005 have been blamed on abuse of the fentanyl patch, along with more than 100 deaths in Florida in 2004. About a week after Knox's death in Farmington, Mo., in March, a second man in the same county was prescribed the patch legally and died after injecting himself with the gel that he had scraped from it.

Emergency-room visits by people misusing fentanyl shot up nearly 14-fold to 8,000 nationwide between 2000 and 2004, according to the U.S. Department of Health and Human Services. The figures do not indicate how many of those ER visits were because of the patch.

(In recent months, more than 100 deaths have been reported from Chicago and Detroit to Philadelphia among drug addicts who overdosed on heroin mixed with fentanyl. And federal drug agents believe fentanyl is being made in clandestine labs in Mexico and elsewhere.)

The first fentanyl patch was Duragesic, made by Johnson & Johnson. Sales more than tripled from 2000 to 2004, according to the Pacific Law Center in La Jolla, Calif. Worldwide sales were more than $2 billion in 2004, and half of that was in the U.S., according to the J&J's Web site.

More than 5.7 million prescriptions were written in 2003 for the Duragesic patch, according to IMS Health.

Mark Wolfe, spokesman for PriCari, the J&J unit that oversees Duragesic, said the product comes with strong "black box" warnings about the dangers of abusing Duragesic.

One theory is that addicts are turning to the fentanyl patch because of a government crackdown on abuse of another powerful prescription painkiller, OxyContin, or oxycodone.

"The abuse of oxycodone and the fear of litigation is enough to scare doctors from prescribing it. Duragesic is in vogue, as we've seen over the last year and a half and two years," said Dr. John Brandt, a chronic-pain specialist at the University of Florida.

In Missouri, the man accused of illegally selling the fentanyl patch to Knox has been charged with murder.

"The awareness is just not out there. I had never heard of this patch," said Knox's mother, Rose Marler. "There's a new generation of drugs and people just need to be aware."