Poison

A substance that, when introduced into the body in relatively small quantities, causes destruction or malfunction of some tissues and organs. Depending on the quantity in the body (the dose), a poison can kill. The word poison usually implies that a substance has no healthful use and is to be considered dangerous even in small quantities. Most common household substances are poisonous, including bleach, ammonia, drain cleaners, paint supplies, and so on.

SUBSTANCES CAUSING DEATHS FROM ACCIDENTAL POISONING

DRUGS

Analgesics and antipyretics
Sedatives and hypnotics
Tranquilizers
Antidepressants
Other psychotropic agents
Other drugs acting on nervous system
Antibiotics and other antimicrobial agents
Cardiovascular drugs
Hormones
Hematological agents
Other drugs

OTHER SUBSTANCES

Alcohols
Cleaning and polishing agents and paint
Petroleum products
Pesticides
Corrosives and caustics

GASES

Utility gas
Carbon monoxide
Nitrogen oxides
Freon
Other gases

In the practice of medicine, many useful DRUGS, such as antibiotics for treating infections or antihypertensive drugs for treating high blood pressure, can be poisonous or toxic in higher doses. Almost all drugs that are abused can be poisonous or toxic; some, even at relatively low doses.

A few drugs that are commonly used in medicine in small amounts to produce important therapeutic effects are also used in other contexts as poisons. For example, the drug warfarin is used medically as an anticoagulant (to increase the time it takes blood to clot), an important effect for people who have had strokes or heart-valve replacement—but warfarin is also used as rat poison, because when rats eat it in large amounts they die soon after from massive hemorrhages. The same "mustard gas" (nitrogen mustards) that, as poison gas, caused much death and suffering in World War I, actually has medical use in the treatment of certain leukemias. Similarly, a series of extremely potent chemicals were developed during World War II as "nerve gases" for warfare, which act by flooding the body with excess acetylcholine (a body substance necessary for synaptic transmission), causing muscle paralysis and death. Consequently, close chemical relatives of some of the most potent nerve gases ever developed are being used to treat medical disorders, such as myasthenia gravis, in which there is not enough acetylcholine in nerve endings.

Treatment of someone who has been poisoned may require removal of the poison from the body (e.g., with the use of a stomach pump for ingested poisons), administration of an antidote if one exists, or simply support in repairing the damage done to the body. Many cities have a telephone "hot line" or poison-control center number where information about poisons, antidotes, and actions to take in case of poisoning can be obtained; often, they will alert emergency medical service (EMS) units to arrive in mere minutes. In case of a poisoning, including a drug overdose, it is essential to call for expert medical help as quickly as possible to minimize damage to the victim.

(SEE ALSO: ; Drug Types; Inhalants; Methanol)

BIBLIOGRAPHY

KLAASSEN, C. D. (1996). Principles of toxicology and treatment of poisoning. In J. G. Hardman et al. (Eds.), The Pharmacological basis of therapeutics, 9th ed. (pp. 63-75). New York: McGraw-Hill.

MICHAEL J. KUHAR