Webster's New World Medical Dictionary

antidiuretic hormone
A peptide hormone
made in the hypothalamus and released at the base
of the brain by the nearby pituitary gland.
Abbreviated ADH. ADH prevents the production of
dilute urine and is therefore antidiuretic. It can also
stimulate contraction of arteries and capillaries, and
it may have effects on mental function. Also known
as vasopressin. See also 
ADH secretion, inappro-
priate; pituitary, posterior.
antiDNAse B
A blood test for antibodies to the
streptococcus B bacteria.
antidote
A drug that counteracts a poison.
antifungal
A medication that limits or prevents
the growth of yeasts and other fungal organisms.
antigen
A substance that the immune system per-
ceives as being foreign or dangerous. The body
combats an antigen with the production of an anti-
body.
antigen, prostate specific
See 
prostate spe-
cific antigen test.
antigen-antibody complex
The complex
formed by the binding of an antibody to an antigen.
Antigen-antibody complexes initiate immune
responses. Also known as an immune complex.
antihistamine
A drug that opposes the action of
histamine released during an allergic reaction by
blocking the action of the histamine on the tissue.
Antihistamines frequently cause dry mouth and
sleepiness. Some antihistamines are nonsedating.
Antihistamine side effects that may occur include
urine retention in males and increased heart rate.
antihypertensive
A medication or another sub-
stance that reduces high blood pressure (hyperten-
sion). See also 
high blood pressure.
anti-infective
An agent that is capable of acting
against infection, either by inhibiting the spread of
an infectious agent or by killing the infectious agent
outright.