What does an opioid overdose do to the body?

Each year in the United States, tens of thousands of people die of drug overdoses (ODs), often involving opioids. And while these deaths have dropped sharply from their 2022 peak of nearly 108,000, ODs continue to claim lives and devastate communities.

John Cunha, DO, FACOEP, an emergency medicine specialist in Fort Lauderdale, Florida, says the majority of opioid overdoses he and his colleagues see in the emergency department (ED) are accidental. Some are related to prescription opioid painkillers such as Percocet, Vicodin, and OxyContin, while many stem from illicit opioids, such as heroin and illegally manufactured fentanyl.

It’s important to understand that opioid ODs can happen to anyone. Dr. Cunha has treated older people who have become addicted to prescription painkillers and children who have overdosed after accidentally ingesting their parents’ medications.

With that in mind, here’s what to know about how opioids work on the body, how to identify an overdose, and steps to take if one occurs.

The effects of opioids on your body

When a person first takes an opioid, either via pill or injection, the drug spreads through the body, explains Cunha. When it hits the brain, it increases the amount of a neurotransmitter called dopamine. This offers a feeling of pleasure and blocks the sensation of pain.

While this is happening, the brain causes certain bodily functions such as heart rate and breathing to slow down. During an overdose—when your body can't handle the amount of opioids you've taken—these functions slow to the point it becomes life-threatening. This affects a person in many different, often observable ways, including:

Breathing problems

While opiates in general cause breathing to become shallow and slow, during an overdose, a person may cease breathing altogether. This can result in brain damage, a coma, or death by respiratory failure. When people die of an OD, it's because they become unable to breathe on their own.

Constricted pupils

“Those who are experiencing an opioid overdose also exhibit pinpoint pupils, where the pupils in their eyes appear to be unusually small under normal lighting,” Cunha says.

Unconsciousness

“Opiates slow the central nervous system and a person may become unresponsive or unconscious,” says Cunha. Along with breathing problems and pinpoint pupils, blacking out is part of the "opioid triad"—three telltale signs someone is overdosing.

Changes in skin tone

Due to lack of oxygen, someone having an overdose may exhibit bluish lips and fingernails, as well as pale or blue skin, which can also be cold to the touch. In people with dark skin tones, skin may seem gray or ashen.

Unfamiliar sounds while sleeping

It’s not unusual for opiate use to cause nausea, Cunha says, but if a person vomits while they are dozing, they may choke. If a sleeping person is making choking, snoring, or gurgling noises (sometimes called a "death rattle") and isn't responsive when you try to wake them, they could be overdosing.

Confusion and delirium

In some cases, an opioid overdose can lead to disorientation and cognitive impairment. Cunha says these symptoms can manifest as confusion, hallucinations, or agitation.

In the event of an overdose

Knowing the signs of an opioid OD can help save lives. If you suspect a loved one has overdosed, Cunha says it’s critical to call 911 immediately.

“An opioid overdose can be reversed if the medication naloxone is administered quickly,” he says. “Often given by first responders and emergency department staff as a nasal spray (Narcan) or injection, it can prevent brain damage in patients by restoring breathing function.”

Once an overdosing person is able to breathe normally, they usually recover, though they still need emergency help for side effects that mirror opioid withdrawal symptoms, such as nausea and vomiting, fever, sweating, and shivering.

Naloxone is increasingly available where people are likely to overdose, including schools, libraries, and homes. Pharmacies offer it with no prescription in every state. In many cities and communities, it is available for free from vending machines.

When your loved one needs help

Because opioids are highly addictive, they can lead to higher tolerances, Cunha says. This can result in people needing a bigger dosage to manage pain or lead them to inadvertently mix opioids with other medications, increasing the risk of overdose. Opioids can be especially dangerous when combined with benzodiazepine medications used for anxiety and insomnia, since both suppress breathing. These include diazepam (Valium) and alprazolam (Xanax), among others. Adding alcohol to the mix makes the danger of overdose even greater.

“The more narcotics a person needs to chase pain, the higher the risk of overdosing,” Cunha says. “I advise patients to avail themselves to good pain management programs and clinics to learn how to manage pain without narcotics, rather than to indefinitely continue relying on opioid medications.”

Speak with a healthcare provider about your options for pain management. If you suspect you or a loved one may have a problem with opioids, the Substance Abuse and Mental Health Services Administration (SAMHSA) offers a free 24-hour helpline, 1-800-662-4357, providing referrals to local treatment facilities.