A narcotic is referred to as an opioid agonist when it acts directly on the brain’s opioid receptors.
This class of drugs begins with morphine, a painkiller derived from opium, and includes oxycodone, hydrocodone, heroin, and methadone. Some drugs related to morphine are partial opioid agonists, meaning they still act on the same brain receptors but much less intensely than full opioid agonists. One of the most important partial opioid agonists today is buprenorphine.
Types of Opioid Agonists
There are several types of opioid agonists, both full and partial, available for both medicinal and illicit uses. Here are a few examples of opioid agonists and how they are used:
- Prescription painkillers: Opioid agonists used as painkillers include morphine, oxycodone, hydrocodone, and fentanyl. These are important medications to treat chronic pain from illness or injury, as well as postsurgical pain. Because these drugs are widely prescribed in the treatment of moderate to serious pain from broken bones, back injuries, or dental surgery, they often become addictive, especially as they are abused for their euphoric properties. Many of these drugs are available on the black market, and people who struggle with addiction to prescription medications like Percocet or Vicodin may turn to illicit sources once they can no longer acquire prescription versions.
- Illicit drugs: The most famous illegal versions of opioid agonists include opium and heroin. However, there are other, illicit formulas of hydrocodone, oxycodone, morphine, and fentanyl that are sold on the black market. These drugs may also be mixed together; for example, an outbreak of overdoses related to fentanyl-laced heroin began in 2014. Fentanyl can enhance heroin’s potency and quickly lead to overdose.
- Maintenance therapy drugs: These drugs are used to help people overcome addictions to other narcotics. These include full and partial opioid agonists. In some cases, a doctor may attempt to taper the prescription dose for a person who struggles with addiction to oxycodone or hydrocodone. In other cases, drugs like methadone are used as replacement or maintenance therapies to help the person undergo other aspects of a rehabilitation program without suffering intense withdrawal symptoms. Oftentimes, doses of these maintenance drugs are lowered over time until the person is fully detoxed from all opioids.
Specific Opioid Agonists Used as Maintenance Therapies
When a person has struggled with addiction to opioids for a long period of time, maintenance therapy, also known as medication-assisted therapy, is one of the primary tools used to help the person overcome their addiction. These medications are used to slowly taper the person off physical dependence on opioid drugs, so they do not experience intense withdrawal symptoms and can focus on therapy to overcome their addiction. While use of these medications can be valuable in recovery, they do not constitute treatment on their own; they must be used in conjunction with therapy.
Drugs used in maintenance therapy include the following:
- Methadone: This drug is a long-acting, full opioid agonist that has been used in the United States since the 1960s to help people overcome addiction to narcotics like heroin. In order to ensure safe use of this potent medication, methadone clinics were opened to dispense specific doses at specific times and to keep track of individuals as they underwent this therapy. Because methadone is so powerful and fully bonds to the opioid receptors in the brain, it has become a target for abuse and fallen out of favor with some experts as a treatment for those attempting to overcome addiction to narcotics.
- LAAM: This is an acronym that stands for levo-alpha acetylmethadol. Also a full opioid agonist, LAAM is longer-acting than even methadone, which can suppress withdrawal symptoms and cravings for a full day. However, LAAM patients have reportedly dropped out of treatment programs due to side effects of the medication, and it is not often recommended as a treatment for people overcoming narcotic addiction.
- Buprenorphine: Currently the most popular form of maintenance medication, buprenorphine was approved for outpatient use by the Food and Drug Administration (FDA) in 2002. Physicians who prescribe other medications can take additional training in order to prescribe buprenorphine to patients who may struggle with opioid addiction. Buprenorphine is a partial opioid agonist, meaning that it does not bind fully to opioid receptors. For most people, buprenorphine relieves withdrawal symptoms and cravings for up to a full day, but does not induce the same euphoria as full opioid agonists, including methadone. However, there are still methods some individuals use to abuse buprenorphine, and the drug can induce a high in people who do not have a tolerance to opiate drugs.
How Maintenance Therapy Works
Although withdrawing or detoxing from opioid drugs is rarely physically dangerous, withdrawal symptoms can be extremely uncomfortable. Body aches, mood swings, and cravings can all lead a person to relapse, in order to stop feeling bad. Relapse is more dangerous than withdrawal because the person loses some of their physical tolerance during withdrawal but then goes back to the same dose, or a higher dose, of the narcotic. This can lead to overdose and death.
Maintenance therapy has several goals, including:
- Reduction or ending use of illegal narcotics
- Preventing injection of opioid drugs to stop the spread of communicable diseases
- Reduced overdose risk
- Reduced criminal activity related to drug abuse
- Improved overall health
In order to reduce the potential for relapse, maintenance drugs are given to those who have struggled with an addiction to narcotics for a long time, at high doses, or both. In part, replacement or maintenance therapy allows the person to break their routine involving drug consumption; if they do not crave the drug because of the replacement therapy, then they learn not to take it. Abusing heroin or prescription painkillers typically means abusing these drugs several times per day in order to maintain a high or to feel normal. When those drugs are replaced in the body with a different opioid agonist, the individual learns, over time, to stop the cycle of addiction by removing the routine of drug consumption from their life.
More importantly, these medications help to prevent relapse because they suppress or prevent the most intense withdrawal symptoms. If a person does not feel these aspects of withdrawal, then their body can slowly return to normal without much disruption to their work, school, and family obligations. It is important for the prescribing doctor to carefully monitor patients during this process, to make sure they are not becoming addicted to or abusing their maintenance drugs. The physician will generally outline a tapering schedule to slowly wean the person’s body off any dependence on opioid drugs, including the maintenance therapy. The average length of a tapering schedule is 2-8 weeks, depending on how high a dose of the replacement drug is needed to stabilize the individual. In some instances, people stay on their maintenance medications for months or years.
Risks of Opioid Agonists
The World Health Organization, along with other national organizations, has found that physician monitoring of patients’ maintenance therapy is the only way for the treatment to succeed. The patient must attend regular visits with the doctor, in the case of buprenorphine prescriptions, or go to a methadone clinic regularly if methadone is prescribed. This allows for patient monitoring. Without this intensive focus on the patient, the patient is much more likely to return to abusing heroin, painkillers, or other narcotics, or to begin abusing the maintenance therapy itself.
Because buprenorphine and methadone are becoming more prevalent on the illicit market, people who have no tolerance to opioids can abuse these drugs and experience a euphoric high, although the high is less intense than that of stronger opioid agonists like fentanyl or heroin. In some cases, a person may also attempt to bypass the slow release through the digestive system by breaking down buprenorphine pills to snort or inject the drug and experience the effects faster. Suboxone, a brand name combination of buprenorphine and the antagonist naloxone, was designed to prevent this kind of abuse, but some individuals have found ways to bypass the naloxone component and experience a high from buprenorphine.
Maintenance therapies are still opioid agonists, either partial or full, and can still cause some effects in the individuals taking them.
Benefits of Long-Acting Opioid Agonists in Maintenance Therapy
- When monitored appropriately by doctors, maintenance therapy can be very effective. The first step is to use the replacement drug to stabilize the individual so they can progress into therapy. Once the person has stabilized in recovery, they can begin to taper the maintenance medication until their body is no longer dependent on it.
- Although the process of withdrawing from opioids can take some time, it is important to undergo all the phases will supervision from medical professionals. Physicians, therapists, and social workers, along with friends and family, are integral to the process of detox and rehabilitation. With the right help, individuals can overcome opioid addiction and embrace balanced lives in recovery.