Drug Overdose Effects – OD Signs, Symptoms, Death in Addiction

Certain drugs are more likely to be misused or abused due to a tendency to be addictive. This addiction may either be psychological or physiological. In the former, a person may display behavior that is characteristic of addiction and feel that they need the drug on a regular basis but do not usually show withdrawal symptoms upon discontinuing the drug. With a physiological addiction, also referred to as a physical addiction, the person will display withdrawal symptoms and an intense craving for the drug on a regular basis which is only eased upon another dose (“hit”).

What is a drug overdose?

A drug overdose (OD) is where a person consumes an excessive amount of a drug and the body is unable to cope with it leading to certain overdose signs, symptoms and complications (acute toxicity/poisoning). The drug or its byproducts (as a result of drug metabolism) is toxic to the body, especially in large quantities associated with overdose, and may lead to death. An overdose may be accidental and this is frequently seen in addicts who require higher doses of a drug to yield the same effects as a result of tolerance that develops over time. An intentional overdose may be associated with an attempt to commit suicide.

Types of Drugs

It is not uncommon for more than one type of drug to be used simultaneously and this may blur the clinical presentation of an overdose. The types of drugs that are most likely to be abused include :


These drugs increase the activity of the central nervous system (CNS) and peripheral nervous system and increase alertness, endurance and improve moods.


  • Amphetamines
  • Methamphetamines (meth)
  • Cannabis
  • Cocaine
  • Ecstasy (MDMA)
  • Ephedrine
  • Pseudoephedrine
  • Phencyclidine (PCP)

Sedative hypnotics

These drugs depress the central nervous system (CNS) and are intended to reduce irritability, anxiety and induce a sense of relaxation and tranquility.


  • Alcohol
  • Barbituates
  • Benzodiazepines
  • GHB (gammahydroxybutyrate)
  • Ketamines


These drugs block the perception of pain by binding with opioid receptors and also induces a sense of euphoria (“high”).


  • Codeine
  • Dipipanone
  • Heroin
  • Methadone
  • Morphine
  • Oxycodone
  • Pethidine
  • Tramadol

Signs and Symptoms of Drug Overdose (OD)

Central Nervous System (CNS)

  • Stimulants
    • Anxiety
    • Insomnia
    • Restless
  • Sedative Hypnotics and Opioids
    • Confusion
    • Hallucinations
    • Slurred speech
    • Drowsy
    • Unconscious


  • Stimulants
    • Rapid breathing
  • Sedative Hypnotics and Opioids
    • Slow breathing rate
    • Signs of reduced perfusion/ventilation


  • Stimulants
    • Dilated pupils
  • Sedative Hypnotics
    • Double vision
    • Squinting (cross-eyed)
    • Nystagmus – involuntary rapid eye movement from side to side
  • Opioids
    • Constricted pupils


  • Stimulants
    • Abdominal pain
    • Diarrhea
  • Opioids
    • Constipation
    • Abdominal pain, bloating


  • Stimulants
    • Tremors
  • Sedative Hypnotics and Opioids
    • Unable to coordinate voluntary movements
    • ‘Limp’ limbs
    • Flaccid muscles

Body Temperature

  • Stimulants
    • High (hyperthermia/fever) – refer to Drug Fever for a list of substances that increase body temperature.
  • Sedative Hypnotics and Opioids
    • Low (hypthermia)

Drug Overdose Death

Death may be a result of a heart attack (myocardial infarction) in drug overdose due to stimulants. With sedative hypnotics and opioid, death may be a result of respiratory failure. However, long terms use of drugs may also cause death due to a number of other reasons like renal failure, cardiac (heart) failure, liver failure and/or repeated strokes.

Related Articles

  1. Drug Fever
  2. Antifreeze Poisoning
  3. Arsenic Poisoning

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