How an Overdose Affects the Brain

The effects of a drug overdose vary widely depending on the drug in question. You can overdose on nearly any substance. It is not only illicit drugs such as heroin that involve the risk of overdose; prescription drugs and over-the-counter drugs also carry risks if taken in excess or combined with other drugs or alcohol. Just as any drug can cause an overdose, anyone can experience an overdose. It is not just drug abusers who overdose, as accidental overdose is possible and does happen. Children are at particular risk for accidental drug overdose and account for more than one million cases of overdose per year.

Drugs that Can Damage the Brain during Overdose

The following list includes drugs that can cause damage to the brain during an overdose. The effects of overdose are not limited to brain damage, as overdose has physical, psychological and social effects as well. Drugs that can affect the brain when taken in overdose and their effects on the brain include following:

  • Acetaminophen (found in Tylenol and opiate painkillers such as Lortab and Percocet). The primary risk of acetaminophen overdose is liver damage, but acetaminophen overdose may also cause encephalopathy (swelling of the brain).
  • Antihistamines. High doses of antihistamines may cause mental disturbance, seizures and coma.
  • Antidepressants. Large doses of antidepressants may cause confusion and seizures.
  • Benzodiazepines (found in antianxiety drugs such as Klonopin, valium or Xanax and in sleep aids such as Ambien). Benzodiazepine overdose may cause dizziness, confusion or coma.
  • Opiates/opioids. Regular use of opiates limits brain function, so overdose on opiate drugs such as heroin or morphine or on opioid drugs such as the prescription pain medications hydrocodone or oxycodone may lead to coma. While the cause of death from opiate overdose is usually depressed breathing, depressed breathing is a result of depression of the central nervous system which is regulated by the brain. Opiates suppress brain activity;, and overdose can cause suppression of automatic functions such as breathing.
  • Stimulants (such as amphetamines, methamphetamine, cocaine, crack cocaine and the prescription stimulants Ritalin or Adderall). Stimulant overdose effects include hallucinations, psychosis, seizures, stroke, brain hemorrhage, coma and death.

Effects of Overdose on the Brain

Many of the effects of drug overdose are physiological. However many drugs can also damage the brain when taken in high doses. Overdose can result in any or all of the following:

  • Confusion
  • Hallucinations
  • Blurred vision
  • Delusions
  • Psychosis
  • Impaired brain function
  • Impaired memory
  • Difficulty concentrating
  • Seizures
  • Swelling of the brain
  • Brain hemorrhage
  • Stroke
  • Coma

Some of these effects may be temporary, while others may be permanent. Many drugs, especially when used regularly over long periods of time, can negatively impact the brain even when not taken in overdose. The physiological effects of drug abuse such as suppressed heart and lung function can cause a lack of oxygen to the brain resulting in permanent brain damage. There is no safe dose of a dangerous drug.

Questions about Preventing Drug Overdose?

If you or a loved one is in danger of overdose or has overdosed and is still using drugs, call our toll-free helpline. We are here 24 hours a day to talk with you, listen to your concerns and provide resources and information. All calls are free and confidential, so there is no reason to hesitate to get the support you need. Call now.