Methadone, a potent opiate once used almost exclusively to treat heroin addicts, is increasingly being prescribed by doctors as a pain medication and abused by drug users searching for a cheap, easy way to get high, physicians and federal drug officials say.
The drug, which comes in pill or liquid form, recently has come under scrutiny in the death of former Playboy model Anna Nicole Smith. A doctor in Studio City prescribed methadone to Smith for pain treatment before she was found dead Feb. 8 in her Hollywood, Fla., hotel suite.
A coroner has yet to determine her cause of death, and the doctor said his treatment was "medically sound and appropriate."
Months earlier, Smith's 20-year-old son died in the Bahamas after taking a lethal mixture of methadone and two antidepressants, Zoloft and Lexapro.
Well before these deaths, however, drug counselors and clinicians were concerned about increased abuse of the drug on the streets, in group homes and even in middle schools.
It is an ironic turn in the history of methadone, which for years has been used to treat heroin addiction.
A synthetic opiate, methadone is similar to heroin in chemistry, curbing a user's craving for the illegal opiate by blocking the sensors that heroin stimulates without producing a heroin high.
In recent years, methadone has proved lethal to a growing number of patients or addicts who use it in conjunction with prescription drugs including Valium, Xanax or, in the case of addicts, illegal narcotics such as cocaine.
Sometimes users swallow methadone before or after they "puff," when they seek to get high by slowly inhaling the chemicals from an aerosol can.
"Every year, we see hundreds of these deaths, and the numbers continue to increase," said Bruce Goldberger, director of toxicology at the University of Florida, who has been at the forefront of tracking methadone-related deaths. "It is absolutely the fastest-growing drug problem."
A federal government study found that nationwide methadone-related deaths climbed to more than 3,800 in 2004 from about 780 in 1999. Among all narcotic-related deaths in 2004, only cocaine killed more people in the United States than methadone.
Physicians and others point out that methadone's potential for abuse isn't as high as that of opiates like heroin because it does not induce a strong euphoria on its own.
But repeated use can still cause a physical dependence, doctors say, and when users stop taking it, withdrawal-like symptoms can occur.
Given its low cost compared with heroin and other drugs, its recent proliferation and its potentially lethal potency when mixed with other drugs, officials worry that methadone is largely evading the scrutiny applied to other abused prescription medications, such as OxyContin and Vicodin.
The drug can be lethal even when mixed with antidepressants, or grapefruit juice, experts and federal drug authorities say.
Methadone can linger in body tissue for an unusually long time -- 24 to 59 hours in some cases. Sometimes users assume it has worn off, then take other drugs or more methadone, leading to respiratory depression, coma and eventual death.
Methadone is available at clinics that prescribe it to treat heroin addiction, from doctors who can prescribe it for pain or to treat addictions and, increasingly, as a street drug.
The clinics face stringent federal and state regulations as to how much methadone they can administer to patients, but physicians don't go beyond a general rule that says they can't prescribe more than a 30-day supply, said Mark Parrino, president of the American Assn. for the Treatment of Opioid Dependence.
In Southern California, parts of downtown, East and South Los Angeles have emerged as places to buy and sell methadone, said Kalante Holmes, a counselor at a methadone clinic in West Los Angeles. "It's one of those easy-to-get things right now," he said.
It's the "easy-to-get" nature of the drug that has led to the recent spike in methadone deaths, experts and government officials say.
As the study of pain has grown over the last five to 10 years, more physicians are prescribing methadone to patients to treat pain, especially chronic and nerve pain.
The Food and Drug Administration issued a warning in November to all physicians saying that misuse of the drug could lead to breathing problems and possible death.
Patients might prefer methadone to other painkillers because not only is it powerful, but it's also less expensive.
For example, a pharmacy can buy a month's supply of methadone for one patient for as little as $8, whereas it would have to pay more than $170 for a similar amount of OxyContin, according to wholesale pharmaceutical price books.