toxic dose

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Related to toxic dose: lethal dose, effective dose

toxic dose (TD)

(in toxicology) the amount of a substance that may be expected to produce a toxic effect. See also median toxic dose.

toxic dose

TD50 Toxicology The calculated dose of a chemical introduced by a route other than inhalation, that would cause a specific toxic effect in 50% of a defined experimental animal population Cf Lethal concentration, Lethal dose.

tox·ic dose

(toksik dōs)
Minimal dose required to produce adverse effects.


(dos) [Gr. dosis, a giving]
1. The amount of medicine or radiation administered.
2. The measurable exposure to an agent, e.g., to a poison, a quantity of radiation, or an irritant in the environment.

absorbed dose

1. Radiation absorbed dose.
2. The amount of a substance ingested, inhaled, or taken up through any protective surface into the body

air dose

The intensity of radiation measured in air at the target.

birth dose

Any dose, e.g., of a vaccine, administered to a neonate. The term is commonly used to describe a neonatal injection of hepatitis B vaccine.

bolus dose

A quantity of fluid or medicine given intravenously at a controlled, rapid rate.

booster dose

See: booster

collective dose

See: cumulative dose

cumulative dose

1. The total medication or radiation dose to which an organism is exposed after repeated treatments.
2. The total ionizing radiation dose resulting from repeated exposures to an occupationally exposed individual over a period of time. This dose can be calculated for whole-body acute exposure or for specific organs or body parts, e.g., the hands.
3. The amount of a drug present in the body after repeated doses.

curative dose

Abbreviation: CD
The dose required to heal an illness or disease.

depth dose

The actual amount of radiation exposure at a specific point below the surface of the body.

dialysis dose

The percentage by which blood urea nitrogen (BUN) is reduced during renal dialysis. Inadequate BUN reductions have been linked to increases in patient care costs, hospitalizations, and increased risk of death in patients with chronic renal failure. See: blood urea nitrogen

divided dose

Fractional portions of a dose administered at specified intervals. For example, a patient may be given 2 g of cephalexin daily, divided as 500 mg orally every 6 hr.

equianalgesic dose

A dose of one form of analgesic drug equivalent in pain-relieving effect to another analgesic. In pain control, this equivalence permits substitution of one analgesic to avoid undesired side effects from another.

equivalent dose

Abbreviation: HT
The biologically active dose of radiation. The damage that a particular absorbed radiation dose will have on living cells and tissues.

erythema dose

Minimal erythema dose.

fatal dose

A dose that kills.
See: median lethal dose

infective dose

The number of infectious organisms, esp. bacteria or viruses, that will cause disease in a healthy organism.

lethal dose

The dose of a substance that results in the death of cells, tissues, or the organism.

lethal dose low

Abbreviation: LDlo
The lowest dose of a substance that will kill at least one exposed organism.

maintenance dose

The dose required to sustain a desired effect.

maximum dose

The largest dose that is safe to administer.

maximum permissible dose

Abbreviation: MPD
The highest dose of radiation to which a person may be exposed over 1 year.


Each U.S. state sets limits on exposure to ionizing radiation. For example, for an adult over 18, the MPD is typically 5 rem (50 mSv). For a pregnant female, the MPD is limited to 0.5 rem (5 mSv).

maximum tolerated dose

Abbreviation: MTD
The most extensive exposure to a treatment that a patient may receive before he or she experiences unbearable side effects.

mean marrow dose

Abbreviation: MMD
An estimated measure of average radiation exposure given to the blood-forming progenitor cells of the bone marrow, e.g., in whole body radiation treatment. The percentage of active bone marrow in the useful beam is multiplied by the average absorbed dose.

median curative dose

A dose that cures half of all treated patients.

median infective dose

Abbreviation: ID50
An infective dose that causes disease in half the subjects exposed to it.

median lethal dose

Abbreviation: LD50
The amount of a substance, bacterium, or toxin that will kill 50% of the animals exposed to it. Dose is usually calculated on amount of material given per gram or kilogram of body weight or amount per unit of body surface area.
See: minimum lethal dose

minimal erythema dose

, minimum erythema dose Abbreviation: MED
The shortest exposure to ultraviolet radiation that produces reddening of the skin within 1 to 6 hr and disappears in 24 hr. The minimal erythemal dose is used to calculate the duration of therapeutic exposure to ultraviolet light. For treatment using a “hot” ultraviolet lamp (UV-A or UV-B), the dose is calculated at a distance of 30 in. The minimal erythemal dose for “cold” ultraviolet (UV-C) is standardized at 30 to 38 sec at a distance of 1 in. Synonym: erythema dose; threshold dose See: table


Burning, edema, and peeling occur at doses at or above the second degree erythemal dose.
Suberythemal dose (SED)No erythema
Minimal erythemal dose (MED)Smallest dose that produces erythema within 1 to 6 hr and disappears within 24 hr
First degree erythemal dose (E1)Erythema lasts for 1 to 3 days. Some scaling of the skin is present. E1 is approximately 2.5 times the MED.
Second degree erythemal dose (E2)Erythema with associated edema, peeling, and pigmentation. E2 is approximately 5 times the MED.
Third degree erythemal dose (E3)Severe erythema and burning with associated blistering, peeling, and edema. E3 is approximately 10 times the MED.

minimum dose

The smallest effective dose.

minimum lethal dose

The smallest amount of a substance capable of producing death.
See: median lethal dose

nursing dose

1. The number of nurses in the work force divided by the population of the community at large.
2. The number of nurses available for clinical responsibilities, divided by the quantity of those duties.

percentage depth dose

In radiation therapy, the ratio of the absorbed dose at a given depth to the absorbed dose at a fixed reference depth. It is dependent on four factors: energy, depth, field size, and source-to-skin distance.

primary dose

An initial, large dose given to provide a high blood level as soon as possible.

radiation dose

1. Energy (joules) deposited by radiation in 1 kg of body tissue.
2. The exposure of a biological system to radiation, measured in rems or sieverts.
3. Radioactivity, measured in curies or becquerels.
See: radiation absorbed dose

radiation absorbed dose

Abbreviation: rad
The quantity of ionizing radiation, measured in rad or gray (Gy), absorbed by any material, e.g., a person, per unit mass of matter. One Gy equals 100 rad.
Synonym: absorbed dose

shock dose

In cardioversion and defibrillation, the energy in joules selected to terminate an abnormal heart rhythm.

skin dose

A radiation dose to the skin including secondary radiation from backscatter.

sublethal dose

A dose containing not quite enough of a toxin or noxious substance to cause death.

stress dose

Stress dosage.

test dose

1. A low dose of a medication given to assess its safety or tolerability.
2. A small dose given to determine its precise effect on living tissues.

therapeutic dose

The dose required to produce the desired effect.

threshold dose

See: minimal erythema dose

tissue culture infective dose

Abbreviation: TCID50
The dose that will produce a cytopathic effect in 50% of the cultures inoculated.

tissue tolerance dose

The largest dose, esp. of radiation, that will not cause obvious or immediate disfunction in tissues.

tolerance dose

The dose of a drug or physical agent, e.g., radiation, that will not cause perceptible or immediate injury. This dose will vary among individuals.

toxic dose

A poisonous dose.

unit dose

A dose of medicine prepared in an individual packet for convenience, safety, or monitoring.
Synonym: monodose
References in periodicals archive ?
This group was treated with toxic doses (60mg/kg/day) of simvastatin alone for 14 days.
However, split tablets are often unequal sizes, which could have serious clinical consequences with drugs that have a narrow margin between therapeutic and toxic doses.
And the results were the following: most of the metals were present in wounds in amounts very much over the normal threshold, and these were in lethal or highly toxic doses (this, for example, in the case of arsenic, aluminum and mercury).
To relieve chronic pain, toxic doses of all approved analgesics are often required.
Radiation exposure became a major concern in October after the FDA said it was investigating 206 cases of patients being exposed to toxic doses of radiation during CT scans of the brain at Cedars-Sinai Medical Center in Los Angeles.
Toxic doses vary according to the size of dog and cocoa solid content of the chocolate, but the charity reckons just one and a half average sized bars could be enough to kill a dog the size of a Yorkshire Terrier.
Supervised taking of the drug can be helpful, but it is important that the recovering addict is a willing participant in this arrangement as there are recorded deaths from overdose with Naltrexone users, who have been trying to overcome the blocking effects of Naltrexone by using toxic doses of heroin.
And as any palliative care doctor will tell you, toxic doses of morphine can result in a patient becoming even more agitated and depressed than they already are.
The Council has agreed to impose restrictions on the addition of iodine in salt, arbitrary use of which may prove dangerous to the extent that the gap between recommended intake and toxic doses is minimal, according to the report tabled by Austrian Socialist Karin Scheele (for the Committee on the Environment, Public Health and Food Safety).
Toxic doses vary according to the size of dog and cocoa solid content of the chocolate but as a rough guide, Dogs Trust estimates 50g of plain chocolate could be enough to kill a small dog such as a Yorkshire Terrier.
With respect to the toxicity data, these vary from reported minimum toxic doses to [LD.
The CHPA statement came on the heels of the Food and Drug Administration's September examination of reports that thousands of Americans unwittingly take toxic doses of acetaminophen and other analgesics, placing themselves at risk for liver damage.