Agonist:
A drug or medication that attaches to and activates specific receptors to stimulate drug actions or effects.

Full opioid agonist:
A drug or medication that stimulates activity at opioid receptors in the central nervous system that are normally stimulated by naturally occurring opioids. Examples of full opioid agonists include morphine, methadone, oxycodone, hydrocodone, heroin, codeine, meperidine, propoxyphene, and fentanyl.

Partial opioid agonist:
A drug or medication that stimulates activity at opioid receptors that does not produce the same maximal effects as a full opioid agonist. Like full opioid agonists this activity occurs at receptors that are normally stimulated by naturally occurring opioids. Under appropriate conditions, partial agonists can produce effects similar to either agonists or antagonists. Buprenorphine is a partial opioid agonist.

Antagonist:
A drug or medication that attaches to but does not activate specific receptors to stimulate drug actions or effects and can block other like-drugs/medications from binding to a receptor (e.g. an opioid receptor). Antagonists can also displace other drugs or medications. When an antagonist displaces an opioid, precipitate withdrawal can occur. Examples of opioid antagonists include naltrexone and naloxone.

Compulsive:
Behavior that is overpowering, repeated, and often irrational.

Craving:
The intense desire for a substance, also known as "psychological dependence."

Dependence:
As a general term, the state of needing or depending on something or someone for support or to function or survive.

As applied to alcohol and other drugs, the term implies a need for repeated doses of the drug to feel good or to avoid feeling bad. In the DSM-IV, dependence is defined as "a cluster of cognitive, behavioral and physiologic symptoms that indicate a person has impaired control of psychoactive substance use and continues use of the substance despite adverse consequences."

Feeling compelled to keep using a drug—even when you realize that you have a physical or psychological problem that is probably caused or made worse by the drug. Dopamine: A naturally occurring chemical that helps to cause feelings of pleasure in the brain. Opioid agonists stimulate dopamine activity.

Dopamine:
A naturally occurring chemical that helps to cause feelings of pleasure in the brain. Opioid agonists stimulate dopamine activity.

Euphoria:
A feeling of pleasure, well-being or of being "high."

Induction:
The first phase of medication-assisted treatment (i.e. buprenorphine), when medication is given to ease a person's withdrawal symptoms. Induction usually lasts one to two days.

Maintenance:
The phase of treatment when the person is taking a stable dose and working with a physician or counselor to address other issues affecting his or her dependence and ability to rebuild his or her life.

Opioid dependence:
A chronic brain disease that involves a physical, psychological, and behavioral need for an opioid drug.

Opiate:
A drug created directly from opium or a naturally-occurring substance, such as a hormone, that has sedative or narcotic effects similar to those of opium. Morphine and codeine are examples of opiates.

Opioid:
A drug with opium-like qualities, which means it reduces pain, causes relaxation or sleepiness, and carries an addictive potential. Opioids can be derived from opiates or can be chemically related to opiates or opium, and include some prescription painkillers, such as oxycodone and hydrocodone. Buprenorphine, methadone, and heroin are opioids. Opioids include some prescription painkillers, such as oxycodone and hydrocodone. Buprenorphine, methadone, and heroin are also opioids.

Opioid receptors:
Specific places in the brain (Central Nervous System) or peripheral nervous system where molecules of opioid drugs or medications attach and start to exert their effect.

Overdose:
When a chemical substance is taken in quantities or concentrations that are large enough to overwhelm the body, causing life-threatening illness or death.

Physical dependence:
A state resulting from a habitual use of a drug where negative physical withdrawal symptoms result from abrupt discontinuation.

Precipitated withdrawal:
Withdrawal symptoms that result when one drug displaces another drug from the receptor, and the drug has no or less effect than the drug it displaced. When SUBOXONE is given before the patient is in mild-to-moderate withdrawal from the opioid he or she has already taken, it can cause withdrawal to occur more rapidly an intensely.

Psychological dependence:
A compulsion to use a substance or engage in a behavior that is psychologically, rather than physiologically, based.

Respiratory failure:
A person stops breathing.

Stigma:
Something that detracts from the character or reputation of a person or group; a symbol of disgrace.

Tolerance:
A decrease in response to a drug dose that occurs with continued use. Individuals who have become tolerant require more drugs or alcohol to achieve the same effects originally produced by lower doses.

Triggers:
Activities, sounds, places, people, images, events, or other things that may cause a dependent person to want to use drugs or alcohol again. Triggers can bring on cravings.

Withdrawal:
The uncomfortable symptoms (such as pain, cramps, vomiting, diarrhea, anxiety, sleep problems, cravings) that develop when a person stops taking a drug or medication on which he or she has become dependent.