How opioids work in the brain: Specialized receptors in the brain accept opioid molecules and, through a biochemical process, release dopamine – a chemical that makes people feel good. Dopamine is also released naturally through exercise, sex, or eating a good meal. To feel ‘normal’, a certain amount of opioid receptors always need to be occupied. In a normal healthy person, the body regulates this naturally by manufacturing the right amount of opioid-like chemicals. Endorphins are one example. The body strives for a state of balance to avoid feeling too good or too bad. High doses of opioid drugs, however, can flood the receptors causing a very high release of dopamine, much more than could ever be released naturally, causing feelings of extreme euphoria. The body responds with a decreased sensitivity to opioids.
Tolerance, physical dependence, addiction: As a person takes opioids for an extended period of time, the opioid receptors become less sensitive as the body tries to maintain normal dopamine levels. This is called tolerance. As a result, the person needs to continually increase the amount of opioids to get the same level of opioid effect. In early tolerance, if opioids are abruptly discontinued, the body can manufacture enough natural opioid-like chemicals to compensate, thus preventing the person from feeling bad. As tolerance increases, the body reaches a point where it can no longer manufacture enough natural opioids to compensate for the increased need of the less sensitive receptors. When this happens, the body has become dependent on the external source of opioids to feel normal. This stage is appropriately called physical dependence, also defined as a physiological state of adaptation to a substance, the absence of which produces symptoms and signs of withdrawal.
Both tolerance and physical dependence are normal physiology, and alone, not reasons for treatment. Both can be resolved with a slow taper off of the opioids. Addiction is something different and only develops in a fraction of the people who take opioids.
Addiction is a behavioral disorder caused by specific brain adaptations and characterized by the repeated, compulsive seeking and/or use of a substance despite adverse social, psychological, and/or physical consequences. It is the consequences of the addictive behavior that ruins lives and the reason people seek treatment. Addiction is often (but not always, as with an addiction to gambling) accompanied by tolerance, physical dependence, and withdrawal syndrome.
Opiate Addiction is a Brain disease
Opioid addiction develops from fundamental, long-term changes to the structure and functioning of the brain. Scientists classify addiction as a chronic disease because areas of the brain are altered from the normal healthy state in long-lasting ways. These are physical changes to the brain that influence behavior – not caused by poor morals, controlled by willpower, nor cured by good advice. It’s a disease as is diabetes or cancer, and it is treatable.
The Drug Addiction Treatment Act of 2000
DATA 2000 enables qualified physicians to prescribe and/or dispense opioid medications for the purpose of treating opioid addiction from an office-based practice. This presents a very desirable treatment option for those who are unwilling or unable to seek help from stigmatizing drug treatment clinics. One medication doctors may now prescribe is buprenorphine.
How it works
Opioid receptor is empty. As someone becomes tolerant to opioids, they become less sensitive and require more opioids to produce the same effect. Whenever there is an insufficient amount of opioid receptors activated, the patient feels discomfort. This happens in withdrawal.
Opioid receptor filled with a full-agonist. The strong opioid effect of heroin and painkillers can cause euphoria andstop the withdrawal for a period of time (4-24 hours). The brain begins to crave opioids, sometimes to the point of an uncontrollable compulsion (addiction), and the cycle repeats and escalates.
Opioids replaced and blocked by buprenorphine. Buprenorphine competes with the full agonist opioids for the receptor. Since buprenorphine has a higher affinity (stronger binding ability) it expels existing opioids and blocks others from attaching. As a partial agonist, the buprenorphine has a limited opioid effect, enough to stop withdrawal but not enough to cause intense euphoria.
Over time (24-72 hours) buprenorphine dissipates, but still creates a limited opioid effect (enough to prevent withdrawal) and continues to block other opioids from attaching to the opioid receptors.
(The above illustrations are for educational purposes and do not accurately represent the true appearance. )
What is Buprenorphine?
At the correct dose, buprenorphine may suppress cravings and withdrawal symptoms and block the effects of other opioids
Buprenorphine (´bu•pre•´nôr•fen) is not new. It was first patented in 1969 and has been used in the U.S. to treat pain and in Europe to treat pain and opioid addiction for over 20 years. Buprenorphine is a semi-synthetic opioid and is a partial agonist.
- Opioid Agonists are drugs that cause an opioid effect; i.e., heroin, oxycodone, hydrocodone, and methadone.
- Opioid Antagonists are drugs that block and reverse the effects of agonist drugs. Narcan® is an antagonist and is used to reverse heroin overdoses.
Buprenorphine can act as both an agonist and antagonist. It attaches to the opioid receptors but only activates them partially, enough to suppress withdrawal and cravings, but not enough to cause extreme euphoria in opioid-tolerant patients. When all available receptors are occupied with buprenorphine, no additional opioid effect is produced by taking more. This is called the ‘ceiling effect’. The antagonist property of the medication expels, replaces and blocks other opioids from the opioid receptor sites. Therefore, if the patient decides to misuse opioid drugs after taking buprenorphine, the effects can be blocked, depending on dosage. Alternately, if buprenorphine is taken too soon after other opioids, by an opioid-physically dependent patient, the buprenorphine can precipitate withdrawal. The ceiling effect, blocking ability, and possibility of precipitating withdrawal contribute to buprenorphine having a favorable safety profile and helps lower the risk of overdose and misuse.
Buprenorphine(Bup) and Buprenorphine/Naloxone(Bup/Nx) combination
In October 2002 the FDA approved the first two prescription Buprenorphine medications for the treatment of opioid addiction; Subutex®* (buprenorphine) and Suboxone®* (buprenorphine/naloxone). Since 2009 the FDA approved generic Bup and Bup/Nx sublingual tablets, the brand-name Bup/Nx sublingual tablet Zubsolv®* and the buccal film Bunavail™*. Both Suboxone and Subutex tablets were discontinued and replaced with Suboxone Film® which is a Bup/Nx sublingual film.
The purpose for the addition of naloxone is to reduce the risk of misuse by injection. If the Bup/Nx combination is injected, the naloxone will help cause immediate withdrawal symptoms in opioid-physically dependent people. However, naloxone is poorly absorbed sublingually. Therefore, when taken as directed, very little naloxone enters the blood. Normally, patients are unaffected by the presence of it, and it is considered clinically insignificant.
Above information credited to The National Alliance of Advocates for Buprenorphine Treatment