What are opioids and why are they dangerous?

Dr. Carrie Krieger, a clinical pharmacist in Medication Therapy Management at Mayo Clinic, says an opioid is a substance that binds to an opioid receptor. "When we talk about opioid medications, what we’re talking about is everything from natural substances, like morphine and codeine, to synthetic substances, like methadone or fentanyl. And, then, there are some that fall in between. We call those semisynthetic, and that includes oxycodone and hydrocodone, which are pretty commonly prescribed."

When used as directed by your health care provider, opioid medications safely help control acute pain, such as pain after surgery. There are risks, though, when the medications are used incorrectly.

How do opioid medications work?
When opioid medications travel through your blood and attach to opioid receptors in your brain cells, the cells release signals that muffle your perception of pain and boost your feelings of pleasure.

"There are different ways opioid medications can be administered," says Dr. Krieger. "Sometimes, it’s through a patch, or sometimes it’s through a pill that we take by mouth. But, ultimately, the opioid gets into the bloodstream and then travels to opioid receptors that are found in the brain. By binding to those receptors, they sort of dull our pain perception by binding to the receptor." Dr. Krieger says they also can produce an effect stimulating the reward center in the brain that causes that pleasure feeling.

Watch: Dr. Krieger discusses what makes opioid medications so dangerous.

Journalists: Broadcast-quality sound bites with Dr. Krieger are in the downloads.

How do opioids differ from over-the-counter pain medications?Acetaminophen (e.g., Tylenol) and some of the nonsteroidal anti-inflammatory drugs, also known as NSAIDs, including ibuprofen and naproxen, work by binding to a different receptor. "In the case of NSAIDs, they bind to a Cox-2 receptor, for example," says Dr. Krieger. "Those receptors have not – or those medications have not – been associated with developing dependence or a tolerance to the medication. Therefore, they’re not at risk for developing addiction associated with those medications."

What makes opioids so dangerous?
What makes opioid medications effective for treating pain also can make them dangerous. At lower doses, opioids may make you feel sleepy, but higher doses can slow your breathing and heart rate, which can lead to death. Also, the feelings of pleasure that result from taking an opioid can make you want to continue experiencing those feelings, which may lead to addiction.