What happens when you take an opioid?

Opioids are powerful medications that relieve pain by lessening pain signals to the brain. Commonly prescribed opioids are hydrocodone (Vicodin), oxycodone (OxyContin, Percocet), morphine (Kadian, Avinza), codeine, and other similar drugs.

What drug does what?

Hydrocodone is prescribed the most (treats a variety of pain such as pain from dental procedures or injuries).  Oxycodone is similar, but more potent, and is usually reserved for more severe pain, or pain not responding to hydrocodone.

Morphine is often used before and after procedures to treat severe pain.

Codeine is used to treat mild pain, and sometimes severe coughs (codeine also suppresses the cough center).

How is the brain affected?

Opioids attach to opioid receptors (special proteins found in the brain, spinal cord, GI tract and other organs). Pain is reduced when drugs attach to specific types of these receptors. Side effects vary and can include: drowsiness, nausea, mental confusion, constipation, and for some opioids, can decrease breathing.

Some people feel euphoria after taking an opioid medication, because the reward region of the brain is affected, but this is not true for everyone.

What is the difference between opioid dependence and addiction?

Dependence happens because of normal adaptions to chronic exposure to a drug. Someone who is dependent will experience withdrawal if he/she abruptly reduces or stops the drug. Symptoms can vary from mild to severe. Dependence can be managed medically by slowly tapering off the drug.

Often, a person who is dependent can develop tolerance and may need a higher dose of medication to get the same effect. This can be difficult for a physician to distinguish (it is sometimes hard to differentiate between the development of a drug problem or a real medical need). This is why physicians must be aware of their patients’ symptoms and function during treatment.

Source: DrugAbuse.gov