LAS VEGAS – Methadone and heroin hold two key advantages for treating patients with opioid addiction: They are inexpensive and readily endorsed by addiction patients, according to Dr. Paul H. Earley.
However, the drugs, which are pure agonists, also hold disadvantages.
"Disadvantages include pontine suppression, the potential for overdose, and prolongation of the QT interval, which, in the course of taking methadone, can lead to torsades de pointes," Dr. Earley said at a psychopharmacology conference sponsored by the Nevada Psychiatric Association. "There’s also a lifelong commitment to pure agonists, like an insulin-dependent diabetic," he said. "They create limited mobility, and you have issues with drug diversion."
Dr. Earley, an addiction medicine physician in Atlanta, went on to discuss his approach to using mixed agonists/antagonists and pure antagonists in patients with opioid addiction. The primary mixed agonist/antagonist he uses is buprenorphine (Suboxone and Subutex), which requires a Drug Enforcement Agency waiver to use for addiction treatment.
"The interesting thing about buprenorphine is that it is an agonist at lower doses but develops more antagonist properties at higher doses," he said. "The drug is extremely safe. Overdosing on this is almost impossible, unlike with heroin and methadone. I use it a lot for detoxification but only rarely for maintenance treatment." In addition, buprenorphine can be used off label for patients with pain and addiction issues.
Establishing a clear contract with patients about this type of treatment is imperative, he said.
"My bias is that buprenorphine is not a state of abstinence," Dr. Earley said. "I think people who are on buprenorphine have a drug load, or an agonist on board, and it is classically different from an individual who does not have narcotics on board.
"It is really a more benign form of opioid maintenance therapy. If I’m going to start someone on buprenorphine, I’ll say, ‘Once you get on this drug, it’s easy to get on, but it is hard to get off of.’ It’s difficult to taper, especially the last few milligrams."
The advantages of mixed agonists/antagonists, he continued, include quick acceptance by patients, and fewer travel restrictions than exist with methadone. In addition, they’re safer than methadone, especially in regard to respiratory depression.
"The disadvantage is that a careful transition from abusable agonists is critical to prevent the inadvertent precipitation of withdrawal," he said. "Drug diversion is a problem, because these agents have a street value."
Pure antagonists used for the treatment of addiction include oral, subcutaneous pellets, or intramuscular naltrexone (Vivitrol). "The advantages are that there is no drug diversion and that you can discontinue at anytime without withdrawal," Dr. Earley said. "That’s a good thing to be able to tell your patients."
Perhaps the most impressive effect of naltrexone is its effectiveness in suppressing drug cravings, Dr. Earley said. The disadvantages include less ready endorsement by the addict, weak adherence to oral naltrexone on the part of patients, and the delicate balance of transitioning patients from detoxification or maintenance agents.
Drug screening is a central part of any addiction practice, he said. "Do not practice addiction psychiatry if you do not understand screening technology and have a high-quality screening lab behind you," he advised.
Before he switches a patient from an agonist to a partial agonist, Dr. Earley said he waits until the person enters withdrawal. "It is best to follow objective signs such as piloerection and pupillary dilation," he said. "The wait is from 6 hours (hydrocodone) to 5 days (methadone) from last dose, and is dependent on the previous agonist dose and other unknown factors, including patient temperament."
Before he switches a patient from a partial antagonist to an antagonist, Dr. Earley said he coaches the person about what to expect and encourages the presence of a "detoxification coach" in the form of a family member or a friend to sit with that person. "I say, ‘You are going to go through some withdrawal, but when we get you on this antagonist, this will be the last time you go through withdrawal, as long as you stay in recovery.’ That often will help people through the difficult times ahead."
Dr. Earley disclosed that he has been a member of the speakers bureau and has received honoraria from Alkermes.