The five major signs of a drug overdose are slow or stopped breathing, unresponsiveness or loss of consciousness, unusual pupil size, changes in skin color, and abnormal body temperature. These signs vary depending on the type of drug involved, but recognizing even one or two of them can be the difference between life and death. In 2024, 79,384 people died from drug overdoses in the United States.
1. Slow, Shallow, or Stopped Breathing
Breathing changes are the single most dangerous sign of an overdose and the leading cause of overdose death. Opioids like fentanyl, heroin, and prescription painkillers suppress the brain’s breathing centers, slowing the rate and depth of each breath. In severe cases, breathing stops entirely. A person overdosing on opioids may take fewer than 10 breaths per minute, make gurgling or choking sounds, or show long pauses between breaths. Their lips or fingertips may turn blue or grayish as oxygen drops.
Sedatives like alcohol and anti-anxiety medications can also slow breathing, especially when combined with opioids or with each other. This is why mixing substances is so dangerous. When taken alone, sedative overdoses often leave vital signs relatively normal, but adding even one other depressant to the mix can push breathing into a critical range.
2. Unresponsiveness or Loss of Consciousness
A person overdosing on a depressant drug (opioids, alcohol, sedatives) will become progressively harder to wake. Early on, this looks like extreme drowsiness or confusion. As the overdose deepens, the person stops responding to their name, to shaking, and eventually to pain. Slurred speech and a limp body are common along the way.
The key distinction between “sleeping it off” and an overdose is responsiveness. If someone won’t wake up when you shout their name and rub your knuckles firmly on their breastbone, that is a medical emergency. Stimulant overdoses can also cause altered consciousness, though it more often looks like agitation, confusion, or seizures rather than sedation.
3. Unusual Pupil Size
Pupil changes are one of the most reliable physical clues to the type of overdose. Opioids cause the pupils to constrict to tiny pinpoints, even in dim lighting. This is so consistent that “pinpoint pupils” are part of what clinicians call the opioid overdose triad, alongside slowed breathing and reduced consciousness.
Stimulants like cocaine and methamphetamine do the opposite. They cause the pupils to dilate widely. If you can see someone’s pupils, this sign alone can help you communicate useful information to emergency responders about what drug may be involved.
4. Changes in Skin Color or Moisture
Skin changes reflect what’s happening inside the body. During an opioid overdose, falling oxygen levels turn the skin pale, bluish, or grayish, particularly around the lips, fingernails, and face. The skin may feel cold and clammy to the touch.
During a stimulant overdose, the picture flips. The heart is racing and blood pressure is spiking, so the skin often appears flushed and feels hot. Excessive sweating is common. A person overdosing on methamphetamine or cocaine may be drenched in sweat while their face looks red or flushed.
5. Abnormal Body Temperature
Stimulant overdoses frequently cause dangerously high body temperature. Methamphetamine and MDMA are particularly known for this. When body temperature climbs past 104°F it becomes a medical crisis on its own, capable of causing organ damage. Cases exceeding 107°F require aggressive emergency cooling. A person who feels burning hot to the touch after using stimulants needs immediate help.
Opioid overdoses tend to lower body temperature, leaving the person feeling cool or cold. While this is less immediately dangerous than extreme heat, it adds to the overall picture of a body that is shutting down.
Opioid vs. Stimulant Overdose at a Glance
- Opioid overdose: pinpoint pupils, slow or stopped breathing, unresponsiveness, pale or blue skin, cold body, limp muscles
- Stimulant overdose: dilated pupils, rapid heartbeat, agitation or seizures, flushed and sweaty skin, dangerously high body temperature
Many overdoses involve more than one substance. Fentanyl is now found mixed into stimulant supplies, so a person may show signs of both types simultaneously. When in doubt, treat any combination of these signs as an emergency.
What to Do if You See These Signs
Call 911 immediately. While waiting for help, check whether the person is breathing. If they are breathing but unconscious, place them on their side in the recovery position: kneel beside them, fold the far arm so the back of their hand rests against the cheek closest to you, bend their far knee to a right angle, then roll them toward you by pulling that bent knee. This keeps the airway open and prevents choking on vomit.
If you suspect an opioid overdose and have naloxone available, use it. Naloxone is available as a nasal spray and as an injectable autoinjector. It reverses opioid effects temporarily, but the overdose can return as naloxone wears off, so staying with the person until paramedics arrive is critical. If breathing has stopped or is very weak, rescue breaths (one breath every 5 to 6 seconds, tilting the head back to open the airway) can keep oxygen flowing to the brain until naloxone takes effect or help arrives.
Naloxone only works on opioids. There is no equivalent reversal drug widely available for stimulant overdoses. For someone showing signs of stimulant toxicity, keeping them cool, preventing injury during seizures, and getting emergency medical help quickly are the most important steps you can take.