How Long Does It Take for an Overdose to Kick In?

An overdose can occur when too much, or more than the recommend amount, of a substance is ingested. Overdoses[i] are serious, especially in the case of drugs or alcohol, if the substance consumed overwhelms the human body’s ability to maintain life-sustaining functions.

In 2016, the Centers for Disease Control and Prevention (CDC) estimated that more than 64,000 Americans[ii] lost their life due to a drug overdose. No one can accurately predict the exact onset of an overdose in any given person. Some people develop symptoms rapidly, while others may experience a significant delay in the start of problems.

How Do Overdoses Occur?

Understanding the unpredictable nature of overdoses requires an understanding of exactly how these dire situations happen in the first place. Alcohol, many prescription medications and a majority of illicit and illegal drugs produce some of their most profound effects by altering the rate of cell-to-cell communication inside the brain. Some substances act as central nervous system stimulants and speed up this communication rate, while other substances act as central nervous system depressants and slow it down.

As the body’s master control center, the brain is designed to work within a relatively narrow set of conditions. When activity levels rise too high, a chain reaction of events can lead to:

• An unusually rapid heartbeat
• Narrowing of the blood vessels accompanied by spikes in normal blood pressure
• Unusually rapid breathing

On the other hand, an abnormally slow rate of brain activity can lead to problems such as:

• An unusually slow heartbeat
• Widening of the blood vessel accompanied by drops in normal blood pressure
• Unusually slow breathing

Overdoses are essentially toxic reactions. They occur when a person consumes enough of a given substance to push the brain out of its safe zone of operation. In a person who overdoses on a central nervous system stimulant (e.g., cocaine or methamphetamine), this change in normal function can lead to outcomes that include an unsustainable strain on the heart and blood vessels. In a person who overdoses on a central nervous system depressant (e.g., alcohol, opioid medications or opioid drugs), it can lead to outcomes that include an unsustainable drop in the amount of oxygen drawn in through the lungs.

Factors That Impact Overdose Risks

Not everyone who engages in substance use or abuse has an equal chance of experiencing an overdose. For example, among people consuming opioid drugs[iii] or medications, risks are highest in people who:

• Have diagnosable symptoms of dependence or addiction
• Use opioids intravenously
• Take large doses of prescription opioids
• Combine opioids with another central nervous system depressant
• Have serious physical conditions that interfere with their normal body function
• Can easily access opioids in their own homes

A variety of other factors can also increase or cut overdose risks for opioid users and users of other substances. These factors include:

• A person’s prior history of involvement in drug or alcohol use
• The degree of tolerance a person has developed to the effects of a given substance[iv]
• A person’s general state of physical health and well-being

Why It’s Difficult to Make Predictions

Even disregarding the potential for an overdose, the physical effects of drugs and alcohol depend on a wide range of possible factors. A short list of these factors includes genetic inheritance, how often substance consumption takes place, how much of a substance is consumed at a time and how rapidly substance consumption occurs in a single session.

If anything, the situation grows even more complex when it comes to estimating the possibility of an overdose and the speed with which an overdose will occur. For example, due to differences in personal background, two people may have wildly different chances of overdosing when consuming exactly the same amount of alcohol, a drug or a medication. These same personal contrasts can have a direct impact on the time it takes for an overdose to kick in. In identical circumstances, one person may develop clear symptoms in a matter of seconds or minutes, while another may start to feel ill effects after a longer period.

A Rapid Response Is Key

When it comes to surviving an overdose, the key is the speed of effective treatment, not the speed of the onset of symptoms. The classic example is opioid overdose, which leads to far more fatalities in the U.S. than any other form of toxic substance reaction. People who take too much of a legal or illegal opioid can easily undergo changes in normal lung function that lead to a complete cessation of breathing. Without emergency treatment, this loss of breathing can quickly result in death.

The accepted emergency antidote for an opioid overdose is a medication called naloxone (brand name Narcan). When inhaled or injected, this medication rapidly counteracts the effects of opioids and helps restore normal breathing. Many emergency personnel across the country now carry Narcan as a standard part of their field kits.

Addiction Treatment Programs

Treatment programs are recognized as one of the most reliable ways to help someone with drug or alcohol problems reduce their overdose risks. At Transformations Treatment Center, our counselors and therapists are experts at creating effective, personalized programs for people struggling with a substance use disorder. We offer customized treatments plans to get our clients started on a personalized journey of recovery while helping you return to a sober, healthy lifestyle.

Medically Reviewed by: Dr. Jawad Daud, MD