SAN FRANCISCO — Denise Williams, a frail and homeless heroin addict, fills her sandwich bag with a dozen clean needles and wanders to the back of the crowded Tenderloin health clinic for a five-minute lesson.
It's a crash course on how to save a life.
Leaning over a dummy on the floor, Williams, 50, practices breathing into the mouth of someone out cold. She then collects two free needles preloaded with naloxone, a medication that can revive an overdosing opiate addict within minutes, and is on her way.
"I'm glad they're showing us this stuff," said Williams, who was revived with a dose of naloxone herself last summer. "I don't want to just sit there if someone ends up in a bad situation."
Mostly because of drug abuse among baby boomers, Californians are dying of overdoses in such large numbers that they may soon surpass auto accidents as the state's leading cause of accidental death.
But here in San Francisco, the death rate from overdose is at its lowest level in nearly a decade.
In 2003, the latest year for which the state has figures, a record 3,691 drug users died, up 42% since 1998 and up nearly 75% since 1990. The total surpasses deaths from firearms, homicides and AIDS.
Meanwhile, overdose deaths in San Francisco, which has one of the highest rates of drug use in the state, have fallen from 178 in 1998 to 144 two years ago. Since then, officials believe, the number may have dropped to fewer than 100 deaths.
The training of addicts to save their brethren is one reason, public health officials say. Officials here have embraced a number of "harm reduction" practices in recent years. And the city has focused primarily on middle-aged users, whose rate of overdose statewide has doubled in the last dozen years.
The approach is controversial because it bypasses the "Say No" and "Get Treatment Now" messages. It assumes overdoses will occur and strives mostly to keep addicts from dying.
Critics, including some physicians, worry that public funding of such a program endorses addiction.
"Addiction is a disease, and overdoses are simply a symptom of the disease," said Dr. David Smith, medical director of the Haight Ashbury Free Clinics, one of San Francisco's largest drug treatment providers, which does not distribute naloxone. "We believe we should be focusing more on getting people into treatment."
Naloxone works by blocking opiates from attaching to the brain's pleasure-seeking receptors. It sends users into immediate -- and often agonizing -- withdrawal. Still, many doctors say the medication does not have proven long-term harmful effects.
In 2003, San Francisco became the first city in the state to publicly fund naloxone distribution, which now costs about $50,000 a year. Since then, officials say, addicts have reported saving 116 people with the medication, although this could not be independently verified.
Naloxone distribution is part of a larger campaign aimed at keeping addicts from getting high by themselves. Four years ago, the public health department began posting "Fix It With a Friend" billboards around the city, highlighting the risks of solo use.
Two of San Francisco's biggest overdose targets are single-room occupancy hotels and the Tenderloin district, because they typically attract older addicts.
Older addicts often use drugs alone, while younger people, research shows, tend to use them in groups. One of the major risk factors for a fatal overdose is not having anyone to call paramedics when the first signs of an overdose appear.
The city also has joined forces with a nonprofit group that sends volunteers to local jails and treatment centers to warn about the risks of starting up drug use again even after a short hiatus. They often pass out "Got Naloxone?" stickers, reminiscent of milk commercials.
Experts estimate that a quarter of overdoses occur soon after addicts leave treatment or jail.
Peter Morse, a pierced and tattooed overdose prevention counselor with the city-supported D.O.P.E. Project (Drug Overdose Prevention and Education), said one of the hardest tasks is convincing people that it's worthwhile to save addicts who are essentially killing themselves.
"This makes their situation not so hopeless," Morse said as he walked down a trash-strewn block in the Tenderloin, which he called one of the city's drug-abuse epicenters. "This doesn't have to be a death sentence for them."
Williams, who has been using heroin since she was 21, said a friend administered naloxone to her early this summer. Minutes later, she woke up on the street as the ambulance was arriving, in pain and nauseated.
"It made me feel cold, and it left a real bad taste in my mouth," she said. "I'm glad they did it, but I didn't like the feeling."
Among junkies, word is spreading about naloxone.
Jack Rocchetti, 40, recently came to a needle exchange seeking naloxone training. He learned about the medication a week before, when one friend used it on another.