Amid the growing awareness of the opioid epidemic in the US, there has been a lot of interest in an experimental “addiction vaccine” that would render opioid drugs useless in anyone who has been vaccinated. This sounds very similar to Vivitrol and other naltrexone drugs that block the effects of opioid drugs. What’s the difference between the experimental vaccine and drugs like Vivitrol that are already in use?
Vivitrol and the vaccine work in a completely different way. Naltrexone, the active ingredient in Vivitrol, is an opioid antagonist. It binds strongly to opioid receptors in the brain, preventing opioids from binding and causing the euphoria and pain-relieving effects typical of opioids. Because naltrexone binds to receptors more strongly than opioids, it also dislodges opioids currently in the brain. So if you haven’t detoxed completely from opioids, taking naltrexone will cause painful rapid detox.
Naltrexone, itself, is also a relatively short-acting drug. Until recently, it had to be taken daily to to ensure opioids wouldn’t affect the brain. Vivitrol is relatively new. It’s an injection that releases naltrexone steadily over the course of a month.
The vaccine, has a much different mechanism. While Vivitrol is sometimes metaphorically called a vaccine, the experimental addiction vaccine is actually functions the same way a vaccine for the measles or flu does. Typically, your immune system does not recognize drugs the way it recognizes a virus or bacteria. This allows the drug to circulate freely in your blood and cross the blood-brain barrier.
The opioid vaccine modifies an opioid molecule in such a way that your immune system can recognize it as a foreign invader. After the vaccine has been introduced, whenever an opioid drug enters your system, your antibodies attack it, just as they would a measles virus. When antibodies attach to the opioid molecules, those molecules can no longer pass through the blood-brain barrier. If opioid molecules can’t enter the brain, they can’t get you high.
An opioid vaccine might have several advantages over Vivitrol. First, it could be longer lasting. Whereas Vivitrol relies on a stockpile of the drug to be effective, the vaccine would make use of your body’s built-in defenses. You would only need occasional boosters to ensure your immune response was robust enough to capture all or at least most of the opioid molecules in your blood. Instead of getting a shot every month, you might be able to go months or years on one vaccine.
Another major advantage of the vaccine is that it could permit recovering addicts to use it along with current medication assisted treatments, or MATs, such as methadone and buprenorphine. Since Vivitrol and MATs fight for the same receptors, you can only use one or the other. This is a problem because Vivitrol does nothing to reduce cravings. Critics of Vivitrol have argued that enforcing abstinence without addressing cravings sets up recovering addicts for a higher risk of fatal overdose. The vaccine would not reduce cravings either, but it would allow for simultaneous MAT, which would help cravings, while the vaccine provides an extra safety net against relapse.
Of course, this is largely speculation. The opioid vaccine has been effective in animals, but human trials are likely several years away.
Located in downtown Midland, The Springboard Center’s mission is to offer programs and services to treat alcohol and drug addiction treatment using an evidence based curriculum, 12 step programs, diet, nutrition, exercise, emotional, mental and spiritual development for a long recovery. For more information, please call us at 432-620-0255 as we are open 24 hours a day, 7 days a week.
