First-pass metabolism Health Dictionary

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First-pass Metabolism: From 1 Different Sources

a process in which a drug administered by mouth is absorbed from the gastrointestinal tract and transported via the portal vein to the liver, where it is metabolized. As a result, in some cases only a small proportion of the active drug reaches the systemic circulation and its intended target tissue. First-pass metabolism can be bypassed by giving the drug via sublingual or buccal routes.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Metabolism

The sum total of changes in an organism in order to achieve a balance (homeostasis). Catabolic burns up, anabolic stores and builds up; the sum of their work is metabolism.... metabolism

Basal Metabolism

The basic rate of combustion by a person, usually measured after sleep and while resting.... basal metabolism

Drug Metabolism

A process by which the body destroys and excretes drugs, so limiting their duration of action. Phase 1 metabolism consists of transformation by oxidation, reduction, or hydrolysis. In phase 2 this transformed product is conjugated (joined up) with another molecule to produce a water-soluble product which is easier to excrete.... drug metabolism

Endotracheal Catheters Are Used To Pass

down the TRACHEA into the lungs, usually in the course of administering anaesthetics (see under ANAESTHESIA).

Eustachian catheters are small catheters that are passed along the ?oor of the nose into the Eustachian tube in order to in?ate the ear.

Nasal catheters are tubes passed through the nose into the stomach to feed a patient who cannot swallow – so-called nasal feeding.

Rectal catheters are passed into the RECTUM in order to introduce ?uid into the rectum.

Suprapubic catheters are passed into the bladder through an incision in the lower abdominal wall just above the pubis, either to allow urine to drain away from the bladder, or to wash out an infected bladder.

Ureteric catheters are small catheters that are passed up the ureter into the pelvis of the kidney, usually to determine the state of the kidney, either by obtaining a sample of urine direct from the kidney or to inject a radio-opaque substance preliminary to X-raying the kidney. (See PYELOGRAPHY.)

Urethral catheters are catheters that are passed along the urethra into the bladder, either to draw o? urine or to wash out the bladder.

It is these last three types of catheters that are most extensively used.... endotracheal catheters are used to pass

Metabolism, Inborn Errors Of

Inherited defects of body chemistry. Inborn errors of metabolism are caused by single gene defects, which lead to abnormal functioning of an enzyme.

Some of these gene defects are harmless, but others are severe enough to result in death or physical or mental handicap. Examples include Tay–Sachs disease, phenylketonuria, Hurler’s syndrome, and Lesch–Nyhan syndrome. Collectively, inborn errors of metabolism affect around 1 child in 5,000.

Symptoms are usually present at or soon after birth. They may include unexplained illness or failure to thrive, developmental delay, floppiness, persistent vomiting, or seizures.

Routine tests are performed on newborn babies for some genetic disorders, such as phenylketonuria.

Treatment is not needed for some inborn errors of metabolism. For others, avoidance of a specific environmental factor may be sufficient. In some cases, the missing enzyme or the protein that it produces can be manufactured using genetic engineering techniques, or a vitamin supplement can help compensate for the defective enzyme. If the enzyme is made in blood cells, a bone marrow transplant may provide a cure.

People with a child or a close relative who is affected may benefit from genetic counselling before planning a pregnancy.... metabolism, inborn errors of

Inborn Error Of Metabolism

any one of a group of inherited conditions in which there is a disturbance in either the structure, synthesis, function, or transport of protein molecules. There are over 1500 inborn errors of metabolism; examples are *phenylketonuria, *homocystinuria, and *hypogammaglobulinaemia.... inborn error of metabolism

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