anthraxA serious bacterial infection of
livestock that occasionally spreads to
humans. In humans, the most common
form of the infection is cutaneous
anthrax, which affects the skin. Another
form, pulmonary anthrax, affects the
lungs. Anthrax is caused by BACILLUS
ANTHRACIS. This microorganism produ-
ces spores that can remain dormant for
years in soil and animal products and
are capable of reactivation. Animals
become infected by grazing on contamin-
ated land. People may become infected
via a scratch or sore if they handle
materials from infected animals. Pulm-
onary anthrax occurs as a result of
inhaling spores from animal fibres.
In cutaneous anthrax, a raised, itchy,
area develops at the site of entry of the
spores, progressing to a large blister
and finally a black scab, with swelling of
the surrounding tissues. This is treat-
able with penicillinin its early stages.
Without treatment, the infection may
spread to lymph nodes and the blood-
stream, and may be fatal. Pulmonary
anthrax causes severe breathing diffi-
culty and is fatal in most cases.
antiallergy drugsDrugs that are used
to treat or prevent allergic reactions
(see allergy). There are several groups,
including corticosteroids, antihistamines,
leukotriene receptor antagonists, and
sodium cromoglicate.
antianxiety drugsA group of drugs
used to relieve the symptoms of anxiety.
Benzodiazepine drugsand beta-blocker
drugsare the 2 main types, although
antidepressant drugsmay occasionally
be used. Benzodiazepine drugs promote
mental and physical relaxation; they
can also be used to treat insomnia, but
their use for this purpose is avoided be-
cause they are addictive. Beta-blockers
reduce only the physical symptoms of
anxiety, such as shaking and palpi-
tations, and are not addictive.
antiarrhythmic drugsA group of drugs
used to prevent or treat arrhythmia
(irregular heartbeat). This group includes
those given intravenously in hospital to
treat arrhythmias that are causing symp-
toms such as breathlessness or chest
pain. Adenosine and bretyllium are
examples of drugs used only in hospital.
A number of drugs are used to prevent
intermittent arrhythmias or to slow the
rate if an arrhythmia is persistent. These
include amiodarone, beta-blocker drugs,
calcium channel blockers, digitalis drugs,
disopyramide, flecainide, lidocaine(ligno-
caine), mexiletine, and procainamide.
Side effects are common and often
include nausea and rash. Some antiar-
rhythmics can result in tiredness or
breathlessness because they reduce the
heart’s pumping ability.
antibacterial drugsA group of drugs
used to treat infections caused by bac-
teria. The term antibacterial was once
used to describe antibiotics that had
been produced synthetically rather than
naturally. The terms are now used inter-
changeably. (See also antibiotic drugs.)
antibiotic drugsA group of drugs used
to treat infections caused by bacteria
and to prevent bacterial infection in
cases of immune systemimpairment.
Most of the commonly used antibiotic
drugs belong to one of the following
classes: penicillins, quinolones, amino-
glycosides, cephalosporins, macrolides,
and tetracyclines. Some antibiotics are
effective against only certain types of
bacteria; others, which are known as
broad-spectrum antibiotics, are effec-
tive against a wide range.
Some bacteria develop resistance to a
previously effective antibiotic drug. This
is most likely to occur during long-term
treatment. Some alternative antibiotics
are available to treat bacteria that have
become resistant to the more com-
monly prescribed drugs.
Most antibiotic drugs can cause nau-
sea, diarrhoea, or a rash. Antibiotics
may disturb the normal balance be-
tween certain types of bacteria and
fungi in the body, leading to prolifera-
tion of the fungi that cause candidiasis
(thrush). Some people experience a
severe allergic reaction to the drugs,
resulting in facial swelling, itching, or
breathing difficulty.
antibodyA protein that is made by cer-
tain lymphocytes (white blood cells) to
neutralize an antigen(foreign protein)
in the body. Bacteria, viruses, and other
microorganisms contain many antigens;
antibodies that are formed againstANTHRAX ANTIBODY
A