Antifungal preparations are available in
various forms including tablets, injec-
tion, creams, and pessaries. Prolonged
treatment of serious fungal infections
can result in side effects that include
liver or kidney damage.
antigenA substance that can trigger an
immune response, resulting in produc-
tion of an antibodyas part of the body’s
defence against infection and disease.
Many antigens are foreign proteins (not
found naturally in the body) such as
parts of microorganisms and toxins or
tissues from another person that have
been used in organ transplants. Some-
times, harmless substances (pollen, for
example) are misidentified by the
immune system as potentially harmful
antigens, which results in an allergic
response (see allergy).
antihistamine drugsA group of drugs
that block the effects of histamine, a
chemical released in allergic reactions
(see allergy). Antihistamines are used
to treat rashes such as urticaria and to
relieve sneezing and a runny nose in
allergic rhinitis. They are also some-
times included in cough remediesand
cold remediesand are used as antiem-
etic drugs. Antihistamines are usually
taken by mouth but may be given by
injection for anaphylactic shock. Many
antihistamines cause drowsiness, but
newer drugs have little sedative effect.
Other possible side effects include loss
of appetite, nausea, dry mouth, blurred
vision, and difficulty in passing urine.
antihypertensive drugsA group of
drugs used in the treatment of hyper-
tensionto prevent complications such
as stroke, myocardial infarction, heart
failure, and kidney damage. There are
several types, including angiotensin II
antagonists, beta-blocker drugs, ACE
inhibitor drugs, calcium channel block-
ers, alpha-blocker drugs, vasodilator
drugs, and diuretic drugs. Side effects
depend on the type of antihypertensive
drugs used, but all can cause dizziness
if the blood pressure falls excessively.
anti-inflammatory drugsDrugs that
reduce inflammation. The main groups
of these drugs are nonsteroidal anti-
inflammatory drugs and corticosteroid
drugs. (See also analgesic drugs.)antimalarial drugsDrugs used to treat
malaria. One antimalarial drug, chloro-
quine, is also used to treat arthritis.
antioxidantA type of chemical that
neutralizes potentially damaging oxidiz-
ing molecules known as free radicals.
Some antioxidants occur naturally in
the body; others (vitamin C, vitamin E,
and beta-carotene, for example) are
obtained through food intake or from
dietary supplements.
antiperspirantA substance applied to
the skin in the form of a lotion, cream,
or spray to reduce sweating. High con-
centrations are sometimes used to treat
hyperhidrosis(abnormally heavy sweat-
ing). Antiperspirants may cause skin
irritation, particularly if they are used
on broken skin. (See also deodorants.)
antiplatelet drugsDrugs that reduce
the tendency of plateletsto stick to-
gether to form blood clots when blood
flow in the arteries is disrupted. This
action reduces the risk of thrombo-
embolism, which can cause potentially
fatal disorders such as a myocardial
infarctionor stroke. Aspirinand dipyri-
damole are commonly used antiplatelet
drugs. Others, such as ticlopidine, are
used specifically to protect against clots
forming in the coronary arteriesof peo-
ple with angina.
antipruritic drugsDrugs that are used
to relieve persistent itching (pruritus).
Antipruritics may be applied as creams
and emollientsand may contain corti-
costeroid drugs, antihistamine drugs,or
local anaesthetics. Oral antihistamines
may also be used to relieve itching.
antipsychotic drugsA group of drugs
used to treat psychoses(mental disor-
ders involving loss of contact with
reality), particularly schizophreniaand
maniain bipolar disorder (see manic–
depressive illness). Antipsychotic drugs
may also be used to sedate people who
have other mental disorders (such as
dementia) and who are very agitated or
aggressive. Antipsychotics include phe-
nothiazine drugs, butyrophenones, such
as haloperidol, and several new drugs
including risperidone, which is used to
treat the symptoms of mania.
Antipsychotics can cause drowsiness,
lethargy, dyskinesia, and parkinsonism.ANTIGEN ANTIPSYCHOTIC DRUGSA