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standard toxic symbol, as defined by Directive 67/548/EEC. skull and crossbones became a standard symbol for poison.]]

In the context of biology, poisons are substances that can cause disturbances to organisms,[1] 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.

Contents

Terminology

Some poisons are also toxins, usually referring to naturally produced substances, such as the bacterial proteins that cause tetanus and botulism. A distinction between the two terms is not always observed, even among scientists.

Animal toxins that are delivered subcutaneously (e.g. by sting or bite) are also called venom. In normal usage, a poisonous organism is one that is harmful to consume, but a venomous organism uses poison to defend itself while still alive. A single organism can be both venomous and poisonous.

The derivative forms "toxic" and "poisonous" are synonymous.

Within chemistry and physics, a poison is a substance that obstructs or inhibits a reaction, for example by binding to a catalyst. For an example, see nuclear poison.

Paracelsus, the father of toxicology, once wrote: "Everything is poison, there is poison in everything. Only the dose makes a thing not a poison." The phrase "poison" is often used colloquially to describe any harmful substance, particularly corrosive substances, carcinogens, mutagens, teratogens and harmful pollutants, and to exaggerate the dangers of chemicals. The legal definition of "poison" is stricter. A medical condition of poisoning can also be caused by substances that are not legally required to carry the label "poison".

Uses of poison

" by Jan Matejko.]]

Throughout human history, intentional application of poison has been used as a method of assassination, murder, suicide and execution.[2][3] As a method of execution, poison has been ingested, as the ancient Athenians did (see Socrates), inhaled, as with carbon monoxide or hydrogen cyanide (see gas chamber), or injected (see lethal injection). Many languages describe lethal injection with their corresponding words for "poison shot". Poison's lethal effect can be combined with its allegedly magical powers; an example is the Chinese gu poison. Poison was also employed in gunpowder warfare. For example, the 14th century Chinese text of the Huo Long Jing written by Jiao Yu outlined the use of a poisonous gunpowder mixture to fill cast iron grenade bombs.[4]

On the whole, however, poisons are usually not used for their toxicity, but may be used for their other properties. The property of toxicity itself has limited non-lethal applications: mainly for controlling pests and weeds, cleaning and maintenance, and for preserving building materials and food stuffs. Where possible, specific agents which are less poisonous to humans have come to be preferred, but exceptions such as phosphine continue in use.

Most poisonous materials still in use are used for their chemical or physical properties other than being poisonous. Many over-the-counter medications, such as aspirin and Tylenol, are quite toxic if ingested in sufficiently large quantities. Alcohol is also toxic if too much is ingested in a short enough time. In laboratory environments, where specific chemical properties are often required, the most effective, easiest, safest, or cheapest option for use in a chemical synthesis may be a poisonous material. If a toxic substance possesses these properties more exactly than a non-toxic one, the toxic substance is superior. Chromic acid is an example of such a "simple to use" reagent, but reactivity, in particular, is important. Hydrogen fluoride (HF), for example, is both poisonous and extremely corrosive. However, it has a high affinity (free energy) for silicon, which is exploited by using HF to etch glass or to manufacture silicon semiconductor chips.

On the other hand, certain medical treatments actually make deliberate use of the toxicity of certain substances. Antibiotics (originally harvested from organisms but now artificially produced in laboratories) are highly disruptive to the biochemistry of micro-organisms while having almost no direct effect upon humans. Similarly, the drugs used in chemotherapy are quite toxic; the reason chemotheraputic drugs have far more severe side effects than antibiotics is that their toxicity is not as narrowly tailored. Their benefit arises from the fact that they are—hopefully—more toxic to cancerous cells than normal ones. Such substances could be classified as poisons under the categories defined above, as they are generally artificial in nature, but are not generally discussed as such.

Biological poisoning

Acute poisoning is exposure to a poison on one occasion or during a short period of time. Symptoms develop in close relation to the exposure. Absorption of a poison is necessary for systemic poisoning. In contrast, substances that destroy tissue but do not absorb, such as lye, are classified as corrosives rather than poisons.

Chronic poisoning is long-term repeated or continuous exposure to a poison where symptoms do not occur immediately or after each exposure. The patient gradually becomes ill, or becomes ill after a long latent period. Chronic poisoning most commonly occurs following exposure to poisons that bioaccumulate such as mercury and lead.

Contact or absorption of poisons can cause rapid death or impairment. Agents that act on the nervous system can paralyze in seconds or less, and include both biologically derived neurotoxins and so-called nerve gases, which may be synthesized for warfare or industry.

Inhaled or ingested cyanide, used as a method of execution in gas chambers, almost instantly starves the body of energy by inhibiting the enzymes in mitochondria that make ATP. Intravenous injection of an unnaturally high concentration of potassium chloride, such as in the execution of prisoners in parts of the United States, quickly stops the heart by eliminating the cell potential necessary for muscle contraction.

Most biocides, including pesticides, are created to act as poisons to target organisms, although acute or less observable chronic poisoning can also occur in non-target organism, including the humans who apply the biocides and other beneficial organisms. For example, the herbicide 2,4-D imitates the action of a plant hormone, to the effect that the lethal toxicity is specific to plants. Indeed, 2,4-D is not a poison, but classified as "harmful" (EU).

Many substances regarded as poisons are toxic only indirectly, by toxication. An example is "wood alcohol" or methanol, which is not poisonous itself, but is chemically converted to toxic formaldehyde and formic acid in the liver. Many drug molecules are made toxic in the liver, and the genetic variability of certain liver enzymes makes the toxicity of many compounds differ between individuals.

The study of the symptoms, mechanisms, treatment and diagnosis of biological poisoning is known as toxicology.

Exposure to radioactive substances can produce radiation poisoning, an unrelated phenomenon.

Poisoning management

  • Poison Control Centers (reachable at 1-800-222-1222 in the US worldwide) provide immediate, free, and expert treatment advice and assistance over the telephone in case of suspected exposure to poisons or toxic substances.

Initial management

Decontamination

  • If the toxin was recently ingested, absorption of the substance may be able to be decreased through gastric decontamination. This may be achieved using activated charcoal, gastric lavage, whole bowel irrigation, or nasogastric aspiration. Routine use of emetics (syrup of Ipecac), cathartics or laxatives are no longer recommended.
    • Activated charcoal is the treatment of choice to prevent absorption of the poison. It is usually administered when the patient is in the emergency room or by a trained emergency healthcare provider such as a Paramedic or EMT. However, charcoal is ineffective against metals, Na, K, alcohols, glycols, acids, and alkalis.
    • Whole bowel irrigation cleanses the bowel, this is achieved by giving the patient large amounts of a polyethylene glycol solution. The osmotically balanced polyethylene glycol solution is not absorbed into the body, having the effect of flushing out the entire gastrointestinal tract. Its major uses are following ingestion of sustained release drugs, toxins that are not absorbed by activated charcoal (i.e. lithium, iron), and for the removal of ingested packets of drugs (body packing/smuggling).[5]
    • Gastric lavage, commonly known as a stomach pump, is the insertion of a tube into the stomach, followed by administration of water or saline down the tube. The liquid is then removed along with the contents of the stomach. Lavage has been used for many years as a common treatment for poisoned patients. However, a recent review of the procedure in poisonings suggests no benefit.[6] It is still sometimes used if it can be performed within 1 h of ingestion and the exposure is potentially life threatening.
    • Nasogastric aspiration involves the placement of a tube via the nose down into the stomach, the stomach contents are then removed via suction. This procedure is mainly used for liquid ingestions where activated charcoal is ineffective, e.g. ethylene glycol.
    • Emesis (i.e. induced by ipecac) is no longer recommended in poisoning situations.[7]
    • Cathartics were postulated to decrease absorption by increasing the expulsion of the poison from the gastrointestinal tract. There are two types of cathartics used in poisoned patients; saline cathartics (sodium sulfate, magnesium citrate, magnesium sulfate) and saccharide cathartics (sorbitol). They do not appear to improve patient outcome and are no longer recommended.[8]

Antidotes

Some poisons have specific antidotes:

Poison/Drug Antidote
paracetamol (acetaminophen) N-acetylcysteine
vitamin K anticoagulants, e.g. warfarin vitamin K
opioids naloxone
iron (and other heavy metals) desferrioxamine, Deferasirox or Deferiprone
benzodiazepines flumazenil
ethylene glycol ethanol, fomepizole or Thiamine
methanol ethanol or fomepizole
cyanide amyl nitrite, sodium nitrite & sodium thiosulfate
Organophosphates Atropine & Pralidoxime
Magnesium Calcium Gluconate
Calcium Channel Blockers (Verapamil, Diltiazem) Calcium Gluconate
Beta-Blockers (Propranolol, Sotalol) Calcium Gluconate and/or Glucagon
Isoniazid Pyridoxine
Atropine Physostigmine

Enhanced excretion

Further treatment

  • In the majority of poisonings the mainstay of management is providing supportive care for the patient, i.e. treating the symptoms rather than the poison.

See also

References

  1. ^ poison at Dorland's Medical Dictionary
  2. ^ Kautilya suggests employing means such as seduction, secret use of weapons, poison etc. S.D. Chamola, Kautilya Arthshastra and the Science of Management: Relevance for the Contemporary Society, p. 40. ISBN 8178711265.
  3. ^ Kautilya urged detailed precautions against assassination—tasters for food, elaborate ways to detect poison. "Moderate Machiavelli? Contrasting The Prince with the Arthashastra of Kautilya". Critical Horizons, vol. 3, no. 2 (September 2002). Brill Academic Publishers. ISSN 1440-9917 (Print) 1568-5160 (Online). DOI: 10.1163/156851602760586671.
  4. ^ Needham, Joseph (1986). Science and Civilization in China: Volume 5, Part 7. Taipei: Caves Books, Ltd. Page 180.
  5. ^ "Position paper: whole bowel irrigation". J Toxicol Clin Toxicol 42 (6): 843–54. 2004. doi:10.1081/CLT-200035932. PMID 15533024. 
  6. ^ Vale JA, Kulig K; American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists. (2004). "Position paper: gastric lavage". J Toxicol Clin Toxicol 42 (7): 933–43. doi:10.1081/CLT-200045006. PMID 15641639. 
  7. ^ "Position paper: Ipecac syrup". J Toxicol Clin Toxicol 42 (2): 133–43. 2004. PMID 15214617. 
  8. ^ Toxicology, American Academy of Clinical (2004). "Position paper: cathartics". J Toxicol Clin Toxicol 42 (3): 243–53. doi:10.1081/CLT-120039801. PMID 15362590. 

External links


Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

See also poisson, and Poisson

Contents

English

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Wikipedia

Pronunciation

Etymology

From Old French puison < Latin potio (drink, a draught, a poisonous draught, a potion) < potare (to drink). See also potion and potable.

Noun

Singular
poison

Plural
poisons

poison (plural poisons)

  1. A substance that is harmful or lethal to a living organism.
    We used a poison to kill the weeds.
  2. Something that harms a person or thing.
    Gossip is a malicious poison.
  3. (idiomatic) A drink; liquor.

Synonyms

Derived terms

Translations

Verb

Infinitive
to poison

Third person singular
poisons

Simple past
poisoned

Past participle
poisoned

Present participle
poisoning

to poison (third-person singular simple present poisons, present participle poisoning, simple past and past participle poisoned)

  1. (transitive) To use poison to kill or paralyse somebody
    The assassin poisoned the king.
  2. (transitive) To pollute; to cause some part of the environment to become poisonous
    That factory is poisoning the river.
  3. (transitive) To cause something to become much worse
    Suspicion will poison their relationship.
    He poisoned the mood in the room with his non-stop criticism.
  4. (transitive) To cause someone to hate or to have unfair negative opinions
    She's poisoned him against all his old friends.

Synonyms

Derived terms

Translations

References

  • poison” in the Online Etymology Dictionary, Douglas Harper, 2001
  • poison in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913

French

Pronunciation

Etymology

Latin potio.

Noun

poison m. (plural poisons)

  1. poison

Derived terms


Simple English

[[File:|right|thumb|150px|The skull and crossbones symbol is traditionally used to label something with poison in it.]]

In biology, poisons are substances that can cause problems to organisms.[1] This is usually done by a chemical reaction. The effect of the poison varies with the quantity that is absorbed by the organism. A dose of poison can cause harmful effects or injuries and sometimes even death. Stuff or substance which has the properties of a poison is poisonous or toxic. If poisoning causes death, it is lethal poison.

Legally and in hazardous chemical labeling, poisons are especially toxic substances. Less toxic substances are labeled "harmful", "irritant", or not labeled at all.

In medicine and zoology, toxins and venoms are different from poisons. Toxins are the result of a biological process. Certain organisms use venoms for hunting, or as a defense. If an organism is poisonous, it is harmful to eat. If it is venomous, it has a harmful bite or sting.

Very often, it is only the quantity of a substance that makes the difference. Drinking alcoholic drinks may lead lead to aggressive behaviour, problems with speech, and different forms of amnesia. This effect is called intoxication. People who drink even more often are in shock. At the same time, alcohol can be used as a disinfectant.

Another example: Drinking water may be deadly: Drinking about ten litres of waters can lead to death for an adult. Water is not poisonous, it is the effect it has, that is, in this case. People will die from a lack of sodium. Drinking the water in smaller doses will give the body time to replace the sodium it loses.

Sometimes, poisons have an antidote. The antidote of a poison will slow or reverse its effects. Note that the antidote may itself be a poison. As an example, Atropine can be used as an antidote against certain nerve gases, like tabun or sarine, or against certain insecticides. It is also used as a drug, In high doses, Atropine is a poison. Atropine is a core medicine in the World Health Organization's "Essential Drugs List".[2]

There are other types of dangerous materials. These are:

Pollution also sometimes is poisonous. For example, large amounts of potato peeling scraps or milk can kill organisms in waterways, because they contain so much nutrients for microbes that the microbes consume all oxygen from the waterway.

Poison gas

In wars, some countries use poison gases against their enemies. Poison gases such as chlorine gas and mustard gas were used in World War I. Corrosive poison gases cause serious burns to the skin, eyes, and lungs. Nerve agents can kill by poisoning.

References

  1. poison at Dorland's Medical Dictionary
  2. "WHO Model List of Essential Medicines" (PDF). World Health Organization. March 2005. http://whqlibdoc.who.int/hq/2005/a87017_eng.pdf. Retrieved 2006-03-12. 


Citable sentences

Up to date as of December 28, 2010

Here are sentences from other pages on Bret Michaels, which are similar to those in the above article.








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