October 7, 2005

New clinic set to fight opioid dependency

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A red-eyed tree frog in Panama. Agalychnis callidryas is one of many species worldwide facing declines.
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New clinic set to fight opioid dependency

Vanderbilt University Medical Center has opened a clinic offering a new office-based treatment for helping opioid-dependent patients, the first of its kind in the region.

Opioids include heroin and other widely prescribed pain control medications that are highly addictive because they attach to opioid receptors in the brain and cause euphoria and the reduction of pain. They can also slow and can potentially stop breathing.

The clinic, which opened July 1, provides the drug buprenorphine to opioid-dependent patients by doctor's prescriptions. This is in contrast to methadone, a synthetic narcotic used for the treatment of opioid dependence, administered on-site, once a day, in a flavored liquid in highly regulated methadone clinics.

Buprenorphine, used for a decade in the United States to treat pain and in Europe to treat opioid dependence, is a synthetic opioid with properties of a partial agonist and a partial antagonist, meaning that it can produce typical opioid agonist effects and side effects such as euphoria and respiratory depression, but its maximal effects are less than those of full agonists like heroin and methadone. It is administered by placing a tablet under the tongue and is rapidly absorbed through thin membranes into the blood vessels.

At low doses buprenorphine produces sufficient agonist effect to enable opioid-addicted individuals to discontinue the misuse of opioids without experiencing withdrawal symptoms. The agonist effects of buprenorphine increase linearly with increasing doses of the drug until at moderate doses they reach a plateau and no longer continue to increase with further increases in dose, what's known as the "ceiling effect." Thus, buprenorphine carries a lower risk of abuse, addiction and side effects compared to full opioid agonists, and most importantly, it blocks the craving for other opioids, so it seems an ideal drug for the treatment of opioid dependent patients.

This new use of buprenorphine is a direct result of the Drug Addiction Treatment Act of 2000 (DATA 2000), which allows, for the first time in more than 30 years, qualified physicians to prescribe and dispense narcotics for the purpose of treating opioid dependence.

“The federal government changed the way of treating opioid-addicted patients because it's been demonstrated that the vast majority are not getting the appropriate treatment,” said Peter Martin, M.D., professor of Psychiatry and Pharmacology and director of the Division of Addiction Medicine in the Department of Psychiatry.

“The only appropriate treatment up until now has been methadone, a long acting opioid that allows the patient freedom from having to go out and regularly seek opioids in an illicit manner, and thus stabilizes their chaotic lives,” Martin said. “Methadone treatment has been demonstrated in randomized controlled studies to reduce morbidity and mortality associated with opioid dependence. Classic opioid addicts are spending most of their lives and energy trying to get opioids on the street, and if they don't have them, they'll go into very severe withdrawal. In addition there are now a significant number of middle-class people who are in quiet desperation dependent on pain killers, who are as severely addicted and also need treatment.”

In October 2002 the FDA approved two prescription buprenorphine medications — Suboxone and Subutex, which will be used at Vanderbilt's clinic. These are the only buprenorphine medications approved by the FDA for the treatment of opioid dependence. Subutex contains only buprenorphine and is intended for use at the beginning of treatment for drug abuse. The other, Suboxone, contains both buprenorphine and the opiate antagonist naloxone, and is used in maintenance treatment of opioid addiction. Suboxone, because it contains the drug naloxone, guards against intravenous abuse of buprenorphine by addicted individuals and diversion and sale on the street.

Martin said that there are five qualified faculty members in the Division of Addiction Medicine who will care for the opioid-addicted patients and each may follow up to 30 patients at one time in the clinic, or a maximum clinic load of 150 patients.

Patients are only accepted if they have failed several attempts to stop using opioids, and are at serious risk for destroying their lives because of their addiction. “These are people whose lives are falling apart without this,” Martin said. “With the medicine, they can stabilize and get their lives back. These are as sick as any patient with cancer or severe heart disease. They have a terrible prognosis without this medicine.”

The patients must come on a regular basis, weekly at first and then less frequently as they stabilize, and be monitored with urine testing for signs of other drugs of abuse. They must also participate in weekly psychotherapy, either in groups or individually. “We don't think buprenorphine works just by itself,” Martin said. “Patients also have to be active in a 12-step program. Buprenorphine is not a standalone medicine. It's a medicine that forms a vital component in an organized system of care.”

Vanderbilt is also participating in a $2 million multi-center study funded by the National Institute of Drug Abuse of the National Institutes of Health to find out the best way to treat pregnant women who are opioid dependent — with methadone or buprenorphine.

“If a woman is pregnant, at this point, the approved treatment of choice is methadone, but the belief is that buprenorphine will be a significant advance in caring for the woman during her pregnancy and ultimately, in the outcome of the child.”

Since the unborn child becomes opioid dependent in utero, it is believed that the severity of the withdrawal for the child after birth will be less with buprenorphine instead of methadone.

Vanderbilt, one of eight sites around the world participating in the study, enrolled its first patient this month. Martin, who is co-principal investigator in the Vanderbilt portion of the study with Karen D'Apolito, Ph.D., R.N., assistant professor of Nursing and director of the Neonatal Nurse Practitioner Program at the Vanderbilt University School of Nursing, said 60 patients will be enrolled at Vanderbilt over the next five years. Also collaborating in the study are Barbara Engelhardt, M.D., associate professor of Pediatrics, Christopher Greeley, M.D., assistant professor of Pediatrics, and Paul Bodea-Barothi, M.D., assistant professor of Psychiatry, Mavis Shorn, R.N., a certified nurse midwife, and Cornelia Graves, M.D., associate professor of Obstetrics and Gynecology and interim director of Maternal Fetal Medicine. The trial is a double blind, double dummy randomized control trial meaning participants will receive both a tablet under the tongue and a fruit-flavored drink, and neither the investigators nor the patients will know which they are receiving.

“It's a very exciting study. We're glad to be a part of it,” Martin said.

For more information about the study, contact Cayce Watson at 936-7075.