What is an opioid overdose?

An overdose is a life-threatening situation that occurs when a person consumes a toxic amount of a drug or combination of drugs, overwhelming the body’s ability to cope. In the case of opioid overdose, this happens when there is such a high level of opioids - or a mixture of opioids and other substances - that the person becomes unresponsive and their breathing slows or stops.

Opioids bind to specific receptors in the brain that regulate pain and also affect the body’s ability to breathe. When breathing is inadequate, oxygen levels in the blood drop, leading to a lack of oxygen in vital organs like the heart and brain. This oxygen deprivation can cause unconsciousness, coma, and ultimately death. Brain damage can begin within 3-5 minutes without enough oxygen, and death follows shortly after. In opioid overdose situations, the person’s survival depends on maintaining breathing and oxygen levels, making ventilation a critical aspect of treatment.

Risk factors for opioid overdose
There are a number of risk factors for opioid overdose [^1]. These include:

• having an opioid use disorder;
• taking opioids by injection;
• resumption of opioid use after an extended period of abstinence (e.g. following detoxification, release from incarceration, cessation of treatment);
• using prescription opioids without medical supervision;
• high prescribed dosage of opioids (more than 100 mg of morphine or equivalent daily).
• using opioids in combination with alcohol and/or other substances or medicines that suppress respiratory function such as benzodiazepines, barbiturates, anesthetics or some pain medications;
• having concurrent medical conditions such as HIV, liver or lung diseases or mental health conditions.

Males, people of older age and people with low socio-economic status are at higher risk of opioid overdose than women, people of young age groups and people with higher socio-economic status.

People who are most likely to witness an opioid overdose are [^1]:

• people at risk of an opioid overdose themselves;
• friends and families of people who use opioids on a regular basis; and
• health-care workers, the emergency services, people providing accommodation to people who use opioids, and peer education and outreach workers as well as others whose work brings them into contact with people who are at risk of overdose.