Overdoses

Overdose refers to the ingestion or exposure to a toxic dose of a substance that overwhelms the body's ability to metabolize or cope, causing harm. Overdoses can be intentional or unintentional and may involve medicines, illegal drugs, alcohol, or a combination of substances. They are a major cause of preventable injury and death in many regions.

Types and substances

Drug overdoses commonly involve opioids (such as heroin and prescription painkillers), benzodiazepines, stimulants, and alcohol. Acetaminophen (paracetamol) overdose is a leading cause of severe liver injury. Poly-substance use—mixing substances—greatly increases risk. The specific symptoms and risks vary by substance but can include altered consciousness, slowed or abnormally rapid breathing, confusion, vomiting, seizures, and abnormal heart rhythms.

Causes and risk factors

Overdose risk increases with higher dose, potency, age, reduced organ function, use of multiple substances, recent cessation of tolerance (such as after a period of abstinence), mental health issues, and barriers to accessing treatment. Certain medications are particularly dangerous when taken in excess or with other depressants.

Signs, symptoms, and complications

Early symptoms may be subtle. Severe overdose can lead to breathing problems, low oxygen, brain injury, coma, or death. Complications include aspiration, hypoxia, cardiac arrest, and liver or kidney damage, depending on the substance.

Prevention and treatment

Prevention includes proper medicine use, secure storage, harm-reduction strategies, and access to treatment for substance use disorders. Naloxone can reverse opioid overdoses and should be used by trained people or emergency responders when indicated. In clinical settings, antidotes and supportive care are used, along with monitoring and treatment of complications.

First aid

If an overdose is suspected, call emergency services immediately. If trained, perform rescue breathing or CPR as needed, monitor responsiveness, and administer naloxone if an opioid overdose is suspected and naloxone is available. Stay with the person until help arrives.