Poison
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In the context of biology, poisons are substances that can cause damage, illness, or death to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism. Legally and in hazardous chemical labelling, poisons are especially toxic substances; less toxic substances are labelled "harmful", "irritant", or not labelled at all.
In medicine (particularly veterinary) and in zoology, a poison is often distinguished from a toxin and a venom. Toxins are poisons produced via some biological function in nature, and venoms are usually defined as biologic toxins that are injected by a bite or sting to cause their effect, while other poisons are generally defined as substances which are absorbed through epithelial linings such as the skin or gut.
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Types of poisons
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The majority of this section is sorted by ICD-10 code, which classifies poisons based upon the nature of the poison itself. However, it is also possible to classify poisons based upon the effect the poison has (for example, "Metabolic poisons" such as Antimycin, Malonate, and 2,4-Dinitrophenol act by adversely disrupting the normal metabolism of an organism.)
(T36-T50) Poisoning by drugs, medicaments and biological substances
(T36) Poisoning by systemic antibiotics
(T37) Poisoning by other systemic anti-infectives and antiparasitics
(T38) Poisoning by hormones and their synthetic substitutes and antagonists, not elsewhere classified
(T39) Poisoning by nonopiod analgesics, antipyretics and antirheumatics
(T40) Poisoning by narcotics and psychodysleptics (hallucinogens)
(T41) Poisoning by anaesthetics and therapeutic gases
(T42) Poisoning by antiepileptic, sedative-hypnotic and antiparkinsonism drugs
(T43) Poisoning by psychotropic drugs, not elsewhere classified
(T44) Poisoning by drugs primarily affecting the autonomic nervous system Neurotoxins interfere with nervous system functions and often lead to near-instant paralysis followed by rapid death. They include most spider and snake venoms, as well as many modern chemical weapons. One class of toxins of interest to neurochemical researchers are the various cone snail toxins known as conotoxins.
Anticholinesterases (T44.0)
Acetylcholine antagonists
Cell membrane disrupters Others
- Nicotine - not strictly a neurotoxin, but capable in large doses of causing heart attack
(T45) Poisoning by primarily systemic and haematological agents, not elsewhere classified
- Phytohaemagglutinin (Red kidney bean poisoning)
(T46) Poisoning by agents primarily affecting the cardiovascular system
(T47) Poisoning by agents primarily affecting the gastrointestinal system
(T48) Poisoning by agents primarily acting on smooth and skeletal muscles and the respiratory system
(T49) Poisoning by topical agents primarily affecting skin and mucous membrane and by ophthalmological, otorhinolaryngological and dental drugs
(T50) Poisoning by diuretics and other unspecified drugs, medicaments and biological substances
(T51-T65) Toxic effects of substances chiefly nonmedicinal as to source
(T52) Toxic effect of organic solvents
(T53) Toxic effect of halogen derivatives of aliphatic and aromatic hydrocarbons
(T54) Toxic effect of corrosive substances Corrosives mechanically damage biological systems on contact. Both the sensation and injury caused by contact with a corrosive resembles a burn injury.
- Acids and bases, corrosives
- Various light metal oxides, hydroxides, superoxides
- Bleach, some pool chemicals, other hypochlorates (acidic and oxydizing effect)
- Hydrofluoric acid
Acids (T54.2) Strong inorganic acids, such as concentrated sulfuric acid, nitric acid or hydrochloric acid, destroy any biological tissue with which they come in contact within seconds.
Bases (T54.3) Strong inorganic bases, such as lye, gradually dissolve skin on contact but can cause serious damage to eyes or mucous membranes much more rapidly. Ammonia is a far weaker base than lye, but has the distinction of being a gas and thus may more easily come into contact with the sensitive mucous membranes of the respiratory system. Quicklime, which has household uses, is a particularly common cause of poisoning. Some of the light metals, if handled carelessly, can not only cause thermal burns, but also produce very strongly basic solutions in sweat.
(T55) Toxic effect of soaps and detergents
(T56) Toxic effect of metals A common trait shared by toxic metals is the chronic nature of their toxicity (a notable exception would be bismuth, which is considered entirely non-toxic). Low levels of toxic metal salts ingested over time accumulate in the body until toxic levels are reached. Toxic metals are often inaccurately referred to as "heavy metals", although not all heavy metals are necessarily harmful and not all toxic metals are heavy metals.
Toxic metals are generally far more toxic when ingested in the form of soluble salts than in elemental form. For example, metallic mercury passes through the human digestive tract without interaction and is commonly used in dental fillings—even though mercury salts and inhaled mercury vapor are highly toxic.
Examples:
- (T56.0) Lead poisoning
- (T56.1) Mercury
- (T56.2) Chromium
- (T56.3) Cadmium
- (T56.7) Beryllium (a highly but subtly toxic light metal)
- Antimony
- Barium
- Thallium
- Uranium
- Cobalt Poisoning
(T57) Toxic effect of other inorganic substances
- (T57.0) Arsenic (see arsenic poisoning)
- Arsenic compounds
Reducing agents
- (T57.1) The most notable substance in this class is phosphorus.
(T58) Toxic effect of carbon monoxide
- (T58) By far the most notable metabolic poison is carbon monoxide, which blocks the ability of red blood cells to transport oxygen.
(T59) Toxic effect of other gases, fumes and vapours
Oxidizers Poisons of this class are generally not very harmful to higher life forms such as humans (for whom the outer layer of cells are more or less disposable), but lethal to microorganisms such as bacteria. Typical examples are ozone and chlorine (T59.4), either of which is added to nearly every municipal water supply in order to kill any harmful microorganisms present.
All halogens are strong oxidizing agents, fluorine (T59.5) being the strongest of all.
- See also: Free radical
(T60) Toxic effect of pesticides
- Pesticide poisoning
- Fluoroacetate is a metabolic poison that blocks a vital step in the citric acid cycle.
- Rotenone is a metabolic poison that disrupts electron transport in cellular respiration.
(T61) Toxic effect of noxious substances eaten as seafood
- Ciguatera poisoning
- Scombroid poisoning
- Shellfish toxins (PSP, DSP, NSP, ASP )
- Domoic acid (or Amnesic shellfish poisoning, ASP)
- Tetrodotoxin
(T62) Toxic effect of other noxious substances eaten as food
- Food poisoning
- Botulin toxin
- Hemlock water dropwort
- Grayanotoxin (Honey intoxication)
- Tetanospasmin (Tetanos Toxin)
(T63) Toxic effect of venomous animals
(T64) Toxic effect of aflatoxin and other mycotoxin food contaminants
- Fungal toxins
- Amanita toxin, see Amanita phalloides
- Muscarine
- Aflatoxins
(T65) Toxic effect of other and unspecified substances
References
See also
- List of poisonous plants
- History of poison
- Antidote
- Venom
- Biosecurity
- Food taster
- LD50
- Lethal injection
- List of poisonings
- List of fictional toxins
- Toxicity
- List of extremely hazardous substances
- Mr. Yuk