page_title: Caffeine
section_title: Overdose
hierarchical_section_title: Caffeine / Overdose
context_page_description: Caffeine is a central nervous system stimulant of the methylxanthine class. It is the world's most widely consumed psychoactive drug. Unlike many other psychoactive substances, it is legal and unregulated in nearly all parts of the world. There are several known mechanisms of action to explain the effects of caffeine. The most prominent is that it reversibly blocks the action of adenosine on its receptors and consequently prevents the onset of drowsiness induced by adenosine. Caffeine also stimulates certain portions of the autonomic nervous system.
  Caffeine is a bitter, white crystalline purine, a methylxanthine alkaloid, and is chemically related to the adenine and guanine bases of deoxyribonucleic acid and ribonucleic acid. It is found in the seeds, nuts, or leaves of a number of plants native to Africa, East Asia and South America, and helps to protect them against predator insects and to prevent germination of nearby seeds. The most well-known source of caffeine is the coffee bean, the seed of the Coffea plant. People may drink beverages containing caffeine to relieve or prevent drowsiness and to improve cognitive performance.
context_section_description: Consumption of 1–1.5 grams (1,000–1,500 mg) per day is associated with a condition known as caffeinism. Caffeinism usually combines caffeine dependency with a wide range of unpleasant symptoms including nervousness, irritability, restlessness, insomnia, headaches, and palpitations after caffeine use.
  Caffeine overdose can result in a state of central nervous system over-stimulation known as caffeine intoxication, a clinically significant temporary condition that develops during, or shortly after, the consumption of caffeine. This syndrome typically occurs only after ingestion of large amounts of caffeine, well over the amounts found in typical caffeinated beverages and caffeine tablets (e.g., more than 400–500 mg at a time). According to the DSM-5, caffeine intoxication may be diagnosed if five (or more) of the following symptoms develop after recent consumption of caffeine: restlessness, nervousness, excitement, insomnia, flushed face, diuresis (increased production of urine), gastrointestinal disturbance, muscle twitching, rambling flow of thought and speech, tachycardia (increased heart rate) or cardiac arrythmia, periods of inexhaustibility, and psychomotor agitation.
  According to the International Classification of Diseases (ICD-11), cases of very high caffeine intake (e.g. > 5 g) may result in caffeine intoxication with symptoms including mania, depression, lapses in judgement, disorientation, disinhibition, delusions, hallucinations or psychosis, and rhabdomyolysis (breakdown of skeletal muscle tissue).
  Death from caffeine ingestion appears to be rare, and most commonly caused by an intentional overdose of medications. In 2016, 3702 caffeine related exposure were reported to Poison Control Centers in the United States, of which 846 required an hospitalization and 16 with a major outcome, and several caffeine-related deaths are reported in case studies. The LD₅₀ of caffeine in humans is dependent on individual sensitivity, but is estimated to be 150–200 milligrams per kilogram (2.2 lb) of body mass (75–100 cups of coffee for a 70 kg (150 lb) adult). There are cases where doses as low as 57 milligrams per kilogram have been fatal. A number of fatalities have been caused by overdoses of readily available powdered caffeine supplements, for which the estimated lethal amount is less than a tablespoon. The lethal dose is lower in individuals whose ability to metabolize caffeine is impaired due to genetics or chronic liver disease. A death was reported in a man with liver cirrhosis who overdosed on caffeinated mints.
  High caffeine consumption in energy drinks (At least 1 liter or 320 mg of caffeine) was associated with short term cardiovascular side effects including hypertension, prolonged QT interval and heart palpitations. These cardiovascular side effects were not seen with smaller amounts of caffeine consumption in energy drinks (less than 200 mg).
  Since there is no antidote nor reversal agent for caffeine intoxication, treatment of mild caffeine intoxication is directed toward symptom relief; severe intoxication may require peritoneal dialysis, hemodialysis, or hemofiltration.
caption: Primary symptoms of caffeine intoxication[118]