Opioids
What are some of the commonly abused other substances?
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Although many other substances can be abused or misused, there are three classes of other substances that are most commonly abused:
Opioids, which are most often prescribed to treat pain;
Opioids
What are opioids?
Opioids are commonly prescribed because of their effective analgesic, or pain-relieving, properties. Medications that fall within this class - sometimes referred to as narcotics - include morphine, codeine, and related drugs. Morphine, for example, is often used before or after surgery to alleviate severe pain. Codeine, because it is less efficacious than morphine, is used for milder pain. Other examples of opioids that can be prescribed to alleviate pain include oxycodone (OxyContin), propoxyphene (Darvon), hydrocodone (Vicodin), and hydromorphone (Dilaudid), as well as meperidine (Demerol), which is used less often because of its side effects. In addition to their pain-relieving properties, some of these drugs - for example, codeine and diphenoxylate (Lomotil) - can be used to relieve coughs and diarrhea.
Source: Office of Applied Studies, Substance Abuse and Mental Health Services Administration. |
How do opioids affect
the brain and body?
Opioids act by attaching to specific proteins called opioid receptors, which are found in the brain, spinal cord, and gastrointestinal tract. When these drugs attach to certain opioid receptors, they can block the transmission of pain messages to the brain. In addition, opioids can produce drowsiness, cause constipation, and, depending upon the amount of drug taken, depress respiration. Opioid drugs also can cause euphoria by affecting the brain regions that mediate what we perceive as pleasure.
Chronic use of opioids can result in tolerance for the drugs, which means that users must take higher doses to achieve the same initial effects. Long-term use also can lead to physical dependence and addiction - the body adapts to the presence of the drug, and withdrawal symptoms occur if use is reduced or stopped. Symptoms of withdrawal include restlessness, muscle and bone pain, insomnia, diarrhea, vomiting, cold flashes with goose bumps ("cold turkey"), and involuntary leg movements. Finally, taking a large single dose of an opioid could cause severe respiratory depression that can lead to death. Many studies have shown, however, that properly managed medical use of opioid analgesic drugs is safe and rarely causes clinical addiction, defined as compulsive, often uncontrollable use of drugs. Taken exactly as prescribed, opioids can be used to manage pain effectively.
Opioids are safe to use with other drugs only under a physician's supervision. Typically, they should not be used with other substances that depress the central nervous system, such as alcohol, antihistamines, barbiturates, benzodiazepines, or general anesthetics, as such a combination increases the risk of life-threatening respiratory depression.
CNS depressants
Stimulants
What are stimulants?
As the name suggests, stimulants are a class of drugs that enhance brain activity - they cause an increase in alertness, attention, and energy that is accompanied by elevated blood pressure and increased heart rate and respiration. Stimulants were used historically to treat asthma and other respiratory problems, obesity, neurological disorders, and a variety of other ailments. But as their potential for abuse and addiction became apparent, the medical use of stimulants began to wane. Now, stimulants are prescribed for the treatment of only a few health conditions, including narcolepsy, attention-deficit hyperactivity disorder, and depression that has not responded to other treatments. Stimulants may be used as appetite suppressants for short-term treatment of obesity, and they also may be used for patients with asthma.
How do stimulants affect
the brain and body?
Stimulants, such as dextroamphetamine (Dexedrine) and methylphenidate (Ritalin), have chemical structures that are similar to a family of key brain neurotransmitters called monoamines, which include norepinephrine and dopamine. Stimulants increase the amount of these chemicals in the brain. This, in turn, increases blood pressure and heart rate, constricts blood vessels, increases blood glucose, and opens up the pathways of the respiratory system. In addition, the increase in dopamine is associated with a sense of euphoria that can accompany the use of these drugs.
The consequences of stimulant abuse can be dangerous. Although their use may not lead to physical dependence and risk of withdrawal, stimulants can be addictive in that individuals begin to use them compulsively. Taking high doses of some stimulants repeatedly over a short time can lead to feelings of hostility or paranoia. Additionally, taking high doses of a stimulant may result in dangerously high body temperatures and an irregular heartbeat. There is also the potential for cardiovascular failure or lethal seizures.
Stimulants should be used with other medications only when the patient is under a physician's supervision. For example, a stimulant may be prescribed to a patient taking an antidepressant. However, health care providers and patients should be mindful that antidepressants enhance the effects of a stimulant. Patients also should be aware that stimulants should not be mixed with over-the-counter cold medicines that contain decongestants, as this combination may cause blood pressure to become dangerously high or lead to irregular heart rhythms.