Dozens of opiates and related drugs (sometimes called opioids) have been extracted from the seeds of the opium poppy or synthesized in laboratories. The poppy seed contains morphine and codeine, among other drugs. Synthetic derivatives include hydrocodone (Vicodin), oxycodone (Percodan, OxyContin), hydromorphone (Dilaudid), and heroin (diacetylmorphine). Some synthetic opiates or opioids with a different chemical structure but similar effects on the body and brain are propoxyphene (Darvon), meperidine (Demerol), and methadone. Physicians use many of these drugs to treat pain.
Opiates suppress pain, reduce anxiety, and at sufficiently high doses produce euphoria. Most can be taken by mouth, smoked, or snorted, although addicts often prefer intravenous injection, which gives the strongest, quickest pleasure. The use of intravenous needles can lead to infectious disease, and an overdose, especially taken intravenously, often causes respiratory arrest and death.
Addicts take more than they intend, repeatedly try to cut down or stop, spend much time obtaining the drug and recovering from its effects, give up other pursuits for the sake of the drug, and continue to use it despite serious physical or psychological harm. Some cannot hold jobs and turn to crime to pay for illegal drugs. Heroin has long been the favorite of street addicts because it is several times more potent than morphine and reaches the brain especially fast, producing a euphoric rush when injected intravenously. But prescription opiate analgesics, especially oxycodone and hydrocodone, have also become a problem.
In anyone who takes opiates regularly for a long time, nerve receptors are likely to adapt and begin to resist the drug, causing the need for higher doses. The other side of this tolerance is a physical withdrawal reaction that occurs when the drug leaves the body and receptors must readapt to its absence. This physical dependence is not equivalent to addiction. Many patients who take an opiate for pain are physically dependent but not addicted: The drug is not harming them, and they do not crave it or go out of their way to obtain it.
For some addicts, the beginning of treatment is detoxification — controlled and medically supervised withdrawal from the drug. (By itself, this is not a solution, because most addicts will eventually resume taking the drug unless they get further help.) The withdrawal symptoms — agitation; anxiety; tremors; muscle aches; hot and cold flashes; sometimes nausea, vomiting, and diarrhea — are not life-threatening, but are extremely uncomfortable. The intensity of the reaction depends on the dose and speed of withdrawal. Short-acting opiates, like heroin, tend to produce more intense but briefer symptoms.
No single approach to detoxification is guaranteed to be best for all addicts. Many heroin addicts are switched to the synthetic opiate methadone, a longer-acting drug that can be taken orally or injected. Then the dose is gradually reduced over a period of about a week. The anti-hypertensive (blood pressure lowering) drug clonidine is sometimes added to shorten the withdrawal time and relieve physical symptoms.
Since the 1970s, professionals who care for opiate addicts have reluctantly recognized that many of them will not or cannot stop taking the drug. The solution is maintenance — dispensing opiates under medical supervision. More than 100,000 American addicts are now using methadone as a maintenance treatment. Although it is still politically controversial, this practice has better scientific support than any other treatment for any kind of drug or alcohol addiction.
Because there is a risk of diversion to the illicit market, addicts must come to specialized clinics for methadone, which they take daily in liquid form. A single dose lasts 24–36 hours, and there are few side effects. Some methadone clinics also provide other medical and social services.
Addicts who switch from illicit opiates to methadone avoid the highs and lows and the medical risks of intravenous injection and the criminal behavior that supports it. Studies show that they are less depressed, more likely to hold a job and maintain a family life, less likely to commit crimes, and less likely to contract HIV or hepatitis. Methadone can be continued indefinitely, or the dose can be gradually reduced in preparation for withdrawal. It has been estimated that about 25% of patients eventually become abstinent, 25% continue to take the drug, and 50% go on and off methadone repeatedly.
A promising approach to maintenance is the partial opioid agonist buprenorphine. This drug is taken three times a week as a tablet held under the tongue. It occupies opiate nerve receptors and produces a mild opiate-like effect. At higher doses, it continues to produce the same weak effect while displacing more potent drugs. In a person who is physically dependent on opiates, buprenorphine causes a withdrawal reaction. There is some risk of abuse if the tablet is dissolved and injected, so buprenorphine has been made available in combination with the short-acting opiate antagonist naloxone, which has little effect when absorbed under the tongue but neutralizes the effect of injected opiates.
The main advantage of this combination, sold under the name Suboxone, is that patients do not have to come to clinics to take it, because there is no illicit market and no danger of diversion. Since 2002, individual physicians with proper training and certification have been allowed to prescribe buprenorphine in their offices for patients to take home.
April 2005 Update