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Glossary of Medical Terms


You will find here some definitions of toxicity-related conditions.

You will find here some definitions of toxicity-related conditions.



The process of transporting the drug from the site of administration to its target in the systemic circulation

A common skin condition of adolescence and early adulthood characterised by non-inflammatory Follicular Papules or comedones (blackheads) and by inflammatory Papules, Pustules and nodules in its more severe forms.

A skin condition characterised by Follicular, papulopustular eruptions confined to the seborrhoeic areas, frequently localised to the face, scalp, upper chest and back. Also referred to as papulopustular rash or folliculitis.

An acute form of leukaemia characterised by overproduction of lymphoblasts.

Absorption, distribution, metabolism, excretion - the four processes that describe a drug's passage through the body.

Pain caused by a stimulus which normally does not provoke pain.

Hair loss or baldness.

A substance taken to neutralise stomach acidity.

A collective term for drugs used to regulate abnormal heart rhythms (arrhythmias).

An illness that causes small ulcers to appear in the mouth, usually inside the lips, on the cheeks, or on the tongue (also known as canker sores or aphthous ulcers).

Equal to the drug dose divided by the area-under-the-curve. Used in pharmacokinetic trials where bioavailability is unknown.

The theoretical volume that the total amount of administered drug would have to occupy, to provide the same concentration as it currently is in blood plasma

A skin condition (also known as eczema cracquelée), which is characterised by pruritic, dry, cracked and polygonally fissured skin with irregular scaling. Often initially appears on the shins and has a ‘crazy paving’ appearance. Other areas that can be affected are the upper arms, thighs and lower back. Asteatotic eczema can cause soreness and itching and is mostly seen in people over the age of 60.

Phosphorylation of a kinase that the kinase mediates by itself.


Inflammation of the skin covering the head (glans) of the penis.

The basal layer is the innermost layer of the epidermis made up of a single layer of basal or germinative cells (mostly epidermal Keratinocytes) that proliferate and divide to give rise to new cells for other epidermal layers. As the cells move to the upper layers of the epidermis they mature and eventually form cornified cells. The suprabasal cell layer lies directly above the basal layer and is composed of five to ten layers of cells.

A measure of the amount of drug that is actually absorbed from a given dose. (The proportion of administered drug that reaches the systemic circulation and is therefore available for distribution to the intended target)

Inflammation of the eyelids.

Abnormally slow heart rate.


Continuous burning pain, allodynia and hyperpathia in succession or a traumatic nervous lesion; disturbed vasomotor functions are often intercurrent, as well as, later on, disturbances to trophism.

Pain associated with a lesion of the central nervous system.

A form of leukaemia characterised by accumulation of myeloid cells in the bone marrow and peripheral blood.

When serum, blood or pus dries on the skin surface, hardened deposits known as Crusts are formed.

Population-based variations in simple sequence repeats of the dinucleotides cysteine and adenosine, which modulate EGFR gene activity.

Drugs used to kill tumour cells directly. Cytotoxic drugs do not differentiate between normal and malignant cells.


A form of cancer that produces tumours in lower layers of the skin.

The movement of a drug to and from the blood and various parts of the body.

Membrane-associated transport proteins that are known to have a role in transporting drugs.

Unpleasant sensation of tingling, stabbing, or burning whether spontaneous or provoked.

Difficulty in swallowing.


The Epithelium lining a sweat gland.


A targeted drug therapy that inhibits the epidermal growth factor receptor (EGFR). Also known as EGFRI.

Removal of a drug from the body.

A protein molecule that accelerates chemical reactions of other substances without itself being destroyed or altered upon completion of the reaction.

A form of leukaemia characterised by overproduction of white blood cells.

Removal of hair using an epilator, an electrical device used to remove hair by mechanically grasping multiple hairs simultaneously.

Outside layer of cells covering all the free, open surfaces of the body including the skin and Mucous membranes.

Redness of the skin caused by dilatation and congestion of the capillaries, often a sign of inflammation or infection.

Abrasions of the skin, usually caused by scratching and often covered by a crust or scab.

A measurement for the amount of drug seen by the body.

The space that surrounds the cells of a given tissue, which is filled with interstitial fluid which bathes and surrounds cells.

The process of discharging moisture or other liquids, through pores or incisions in the skin.


An effect where orally-administered drugs are substantially reduced in bioavailability on the "first pass" of the liver and gut wall.

Cracks in the skin caused by Xerosis in areas where the epidermis is thick (eg tops of fingers or toes, knuckles and nail folds).

A small cavity in the epidermis of the skin from which a hair develops.

Affecting or growing out of a Follicle or Follicles.

Inflammation of the hair Follicles, which is often caused by Staphylococcal infections.


Natural variation in the genetic code between different individuals.

The nth root of the product of a group of numbers numbering n, contrasted with the more well-known arithmetic mean.

Drugs that have has glucuronic acid added to them.


A type of drug that blocks histamine receptors on parietal cells to decrease acid production in the stomach.

The period of time in which the amount of a drug in the body is reduced by one half.

A dose-dependent skin reaction characterised by sharply demarcated, erythematous, oedematous, painful and very tender blisters that evolve into inflamed and painful skin adjacent to the calluses. The lesions typically localize to areas of pressure or friction on the skin, such as on the heels, metatarsal heads, and areas of friction caused by shoes or manual labour.

Also know as Palmar-Plantar Erythrodysethesia (PPE), as a skin toxicity associated with oedema, and dysesthesia with pain, scaling, and vesiculation, often associated with chemotherapy.

A potassium channel protein essential for cardiac electrical function. Mutations in the gene cause long QT syndrome.

A structure formed when two molecules of the same type of protein (eg Receptor proteins) combine.

Increase in sensitivity to specific stimuli.

Increased response to a stimulus which is normally painful.

A disease that causes organ damage due to high numbers of blood leukocytes.

Hyperkeratosis is a thickening of the stratum corneum of the skin.

Painful syndrome characterised by increased reaction to a stimulus, especially a repetitive stimulus.

Excessive hair growth.

Low levels of potassium in the blood.

Low levels of magnesium in the blood.


Inward cell membrane transport of drugs, mediated by drug transporters.

Instrumental ADL (activities of daily living); refers to preparing meals, shopping for groceries or clothes, using the telephone, managing money, etc.

Transport of drugs through the intestinal lining.

The space contained within blood vessels. The main intravascular fluid is blood.


Specialised epidermal cells that synthesises keratin.

A low-grade skin cancer tumour.

A kinase enzyme modifies other proteins by chemically adding phosphate groups to them by phosphorylation.

A type of inhibitor that blocks the action of one, or more than one, protein kinase


Epidermal thickening characterised by visible and palpable thickening of the skin and accentuated skin markings. Usually occurs as a result of constant scratching and/or rubbing.

A small molecule that binds to a larger molecule called a receptor.


A flat, distinct, coloured area of skin that is less than 1 centimetre in diameter and does not include a change in skin texture or thickness.

A skin condition characterised by a flat, red area on the skin that is covered with small confluent bumps (papules), and also includes erythema.

Treatment to prevent relapse in cancer patients.

Chemical transformation of ingested molecules including drugs.

Linings of body cavities and various internal organs that are exposed to the external environment. Mucous membranes are covered in Epithelium and are involved in the processes of absorption and secretion.

A type of enzyme inhibitor that blocks the action of more than one protein kinase.


For grading purpose and use of common language in the CTCAE v4.03 Paronychia is addressed as Nail Infection, a disorder characterised by an infectious process involving the nail.


A condition marked by pain, swelling, numbness, tingling, or redness of the hands or feet. See also Hand-foot syndrome.

A benign outwardly-projecting epithelial tumour.

Circumscribed palpable elevations of the skin less than 0.5 cm in diameter.

A skin condition characterised by follicular, papulopustular eruptions confined to the seborrhoeic areas, frequently localised to the face, scalp, upper chest and back. Also referred to as acneiform rash or folliculitis.

Abnormal sensation, either spontaneous or evoked.

Inflammation of the nail fold.

The soft tissue surrounding the border of the fingernail or toenail.

An important consideration for drugs that treat hypertension. The ratio of blood pressure lowering by the drug, at the maximum and minimum blood pressures in a 24-hour period.

The negative log of the measure of hydrogen ions in a solution.

A novel mutant chromosome that usually appears associated with chronic myelogenous leukaemia.

Unit containing the hair shaft, hair follicle, Sebaceous gland and the erector pili muscle.

Pertaining to the branch of medicine that deals with the diagnosis, treatment and prevention of diseases of the human foot.

A type of ventricular tachycardia where the tachycardiac complexes have varying shapes.

A type of drug that inhibits viral proteases, used to treat certain viral infections like HIV.

A type of drug that reduced gastric acid production, used to treat a number of gastrointestinal conditions.


A small amount of visible pus in the top layer of skin (epidermis) or just beneath it in the dermis.

A common, benign growth that often appears as a rapidly growing, bleeding bump on the skin or inside the mouth. It is composed of blood vessels and may occur at the site of minor injury.


A measure of delayed ventricular repolarisation.


A large-molecular-weight protein that contains a region where small molecules or ligands can bind.

A skin disease characterised by redness (Erythema) of the face, flushing of the skin and the presence of hard pimples (Papules) or pus-filled pimples (Pustules), and small visible spider-like veins called Telangiectasias. In later stages of the disease, the face may swell and the nose may take on a bulb-like appearance called rhinophyma.


The Epithelium lining a Sebaceous gland.

A cutaneous gland that empties an oily secretion (sebum) into the hair Follicle to lubricate the hair and skin.

Self care ADL (activities of daily living); refers to bathing, dressing and undressing, feeding self, using the toilet, taking medications, and not confined to bed.

A cancer type that develops from epidermal keratinocytes.

A general term for any mucosal injury in the oral cavity.

The part of the cardiovascular system responsible for transporting blood around the body (as opposed to pulmonary circulation to the lungs).


Dilated superficial blood vessel in the skin.

The range of doses of a drug that can be used to treat a disease.

A form of polymorphic ventricular tachycardia that is characterised by a prolonged QT interval.

Excessive hair growth resulting in long, curly and rigid eyelashes.

An Enzyme that transfers a phosphate from ATP, activating the EGFR. Kinase activity is an important component of intracellular signalling.


Abnormal dryness of the eye and thickening of the conjunctiva.


Dry skin.

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