Painkillers fuel growth in drug addiction

Published: January, 2011

Opioid overdoses now kill more people than cocaine or heroin.

Opioid drugs such as oxycodone (OxyContin), hydrocodone (Vicodin), and meperidine (Demerol) are among the most powerful painkillers available. Opioids are used both to treat severe acute pain (limited in duration, such as following surgery) as well as various types of chronic pain (lasting longer than three months).

Consensus exists that prescribing opioids for chronic pain caused by cancer or experienced at the end of life is appropriate and humane. Much more controversial is the practice of prescribing these medications for other types of chronic conditions, such as arthritis, migraine, or back pain. Opioids target the same brain receptors as heroin, causing euphoria. As such, a risk of long-term opioid therapy is addiction, usually defined as the development of abuse or dependence (see "Addiction terminology").

The issue of painkiller addiction is receiving more attention because prescriptions for opioids have increased tenfold since 1990. Paralleling this trend, the number of people addicted to painkillers has also increased over time.

Columbia University researchers found that opioid addiction had tripled over a 10-year period, with the proportion of Americans reporting abuse or dependence increasing from 0.1% of the population in 1991–92 to 0.3% in 2001–02. The 2009 National Survey on Drug Use and Health found that nearly two million Americans were dependent on or abusing prescription pain relievers — nearly twice as great as the number of people addicted to cocaine.

According to the latest statistics compiled by the Centers for Disease Control and Prevention, in 2007 painkillers killed twice as many people as cocaine and five times as many as heroin. Opioid painkiller addiction was also more common than abuse of or dependence on any other type of prescription drug.

Addiction terminology

The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) describes criteria for substance dependence and abuse, rather than addiction.

Dependence. This occurs when at least three of the following symptoms or behaviors appear over time: greater tolerance of the substance, withdrawal symptoms, ongoing desire to quit using, loss of control over quantity used, greater focus on obtaining or using the substance, less focus on responsibilities at work and home, and continuing to use in spite of problems.

Abuse. This describes people who don't have the same compulsion or physical need to use a substance as those with dependence, but who use it on a regular basis. As a result, they may fail to fulfill major responsibilities, continue using the substance even though it imperils relationships, or incur other types of problems.

Who is at risk

On television shows, drug addicts are often depicted as criminal characters making deals on dark street corners. In fact, people using opioids for nonmedical purposes are most likely initially to obtain them from friends or family members (see "Sources of painkillers," below).

Furthermore, although people with chronic pain are more likely than others to receive prescriptions for opioids, the risk of developing a painkiller addiction depends on more than just prolonged exposure to these drugs. For this reason, it's important that clinicians conduct a comprehensive medical and psychiatric evaluation of patients before prescribing an opioid medication.

In its clinical guidelines for prescribing opioids, the American Pain Society notes that the most significant risk factor for developing a painkiller addiction is a personal or family history of an alcohol or other substance use disorder. One review of 24 studies found that patients with chronic pain who also had a current or past substance use disorder were about 17 times as likely to develop a painkiller addiction as other chronic pain patients.

Another risk factor is age. Teenagers and young adults are more likely than older adults to abuse or become dependent on opioid painkillers. An analysis of national studies from 2002 to 2004 found that slightly more than 1% of people ages 12 to 25 were abusing or dependent on painkillers — roughly double the percentage in people ages 26 to 49, and six times the percentage in those 50 and older.

Sources of painkillers

The 2009 National Survey on Drug Use and Health revealed that when painkillers are used for nonmedical reasons, they are usually obtained from a friend or family member.

graph showing where abused painkilles are obtained

Source: Substance Abuse and Mental Health Services Administration

Treatment options

Because opioid addiction creates long-term changes in the brain, people undergoing treatment not only experience debilitating withdrawal symptoms but are also prone to relapse because of cravings. Treatment therefore is most successful when it consists of two phases: detoxification from the painkillers, followed by a longer (and sometimes indefinite) maintenance phase. Although counseling is an important part of treatment, most people addicted to painkillers require medication treatment during both detoxification and maintenance therapy.

Choice of which medications to use depends on how severe the painkiller addiction is, how motivated the patient is to change, and whether the patient wants to ensure that treatment remains private. The two most commonly used medications, methadone and buprenorphine, can be used during both detoxification and maintenance therapy.

Methadone. This longstanding treatment of opioid addiction binds to opioid brain receptors effectively and for a prolonged time. A single dose can ease or prevent opioid withdrawal symptoms and alleviate cravings for at least 24 hours. Once a patient has progressed through detoxification from painkillers, a daily dose of methadone is usually sufficient.

Because methadone can be abused at doses higher than those used for detoxification or maintenance, methadone is available only through specialized clinics. Research suggests that methadone maintenance therapy is especially effective at helping people remain in treatment, perhaps because of ongoing clinical monitoring.

The most common side effects of methadone treatment are slowed breathing and irregular heart rate, which are both most dangerous at the beginning of treatment. For this reason, physical monitoring is necessary and is especially important any time the dose is increased.

Buprenorphine. This medication (Subutex) is a partial agonist for opioid receptors, which means it is less efficient than a medication like methadone. One advantage is that buprenorphine can relieve withdrawal symptoms while delivering less of a "high." Another is that people are less likely to misuse this drug because increasing the dose typically will not provide more euphoria. It is also harder to take a dangerous overdose of buprenorphine. As a result, people using this medication do not need to make daily visits to a specialty clinic. Instead, clinicians in private practice can prescribe buprenorphine as long as they have the appropriate license and agree to provide drug counseling (or refer the patient elsewhere to obtain it).

Even so, buprenorphine treatment presents several challenges. Because some patients do use buprenorphine alone to get high, clinicians usually prescribe buprenorphine plus naloxone (the combination is marketed as Suboxone). Naloxone blocks the effects of narcotics. When the patient takes the pill sublingually (under the tongue) as directed, very little naloxone is digested and absorbed into the bloodstream. But if the patient crushes the pill for swallowing or injection, naloxone floods the bloodstream, neutralizing the slight "high" from buprenorphine while causing unpleasant side effects.

Although buprenorphine is quite effective, a practical challenge is finding a way to ensure that patients continue taking this medication as prescribed, especially since they do not have to undergo the type of daily monitoring necessary for methadone treatment. Researchers are responding to this concern by testing time-release versions of buprenorphine, such as an implant or a long-acting depot (injected) formulation.

Naltrexone. This medication (Depade, ReVia) is FDA-approved for treating dependency on either alcohol or opioids. Unfortunately, because naltrexone causes unpleasant side effects, most patients eventually stop taking it.

To address problems in patient adherence, the FDA approved a sustained-release injectable formulation of naltrexone (Vivitrol) for opioid addiction. Although the research suggests this formulation, injected once a month, is more effective than placebo, it remains unclear how it compares with methadone or buprenorphine.

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