may occur but usually disappear as
treatment continues.
prolactinA hormoneproduced by the
pituitary gland. Prolactin helps to stimu-
late the development of the mammary
glands (see breast), and to initiate and
maintain milk production for breast-
feeding. (See also prolactinoma.)
prolactinomaA noncancerous tumour
of the pituitary glandthat causes over-
production of prolactin. In women, this
may result in galactorrhoea, amenor-
rhoea, or infertility. In men, it may cause
impotenceand gynaecomastia. In either
sex, it may cause headaches, diabetes
insipidus, and, if the tumour presses on
the optic nerves, loss of the outer visual
field. Diagnosis is made from blood tests
and CT scanningor MRIof the brain.
Treatment may involve removal of the
tumour, radiotherapy, or giving the drug
bromocriptine.
prolapseDisplacement of part or all of
an organ or tissue from its normal posi-
tion in the body (see uterus, prolapse of;
disc prolapse).
promazineA phenothiazine-type anti-
psychotic drugused as a sedative drug.
Possible adverse effects include abnor-
mal movements of the face and limbs,
drowsiness, lethargy, dry mouth, consti-
pation, and blurred vision. Long-term
treatment may cause parkinsonism.
promethazineAn antihistamine drug
used to relieve itching in a variety of
skin conditions, such as eczema. It is
also used as an antiemetic drug, and
sometimes as a premedication. Possible
adverse effects include dry mouth,
blurred vision, and drowsiness.
pronationThe act of turning the body
to a prone (facedown) position, or the
hand to a palm backwards position.
propanthelineAn antispasmodic drug
used to treat irritable bowel syndrome
and forms of urinary incontinence. Pos-
sible adverse effects include dry mouth,
blurred vision, and retention of urine.
prophylacticA drug, procedure, or piece
of equipment used to prevent disease;
also a condom.
propranololA beta-blocker drugused
to treat hypertension, angina pectoris,
and cardiac arrhythmias. It may also be
used to reduce the risk of further heartdamage after myocardial infarction. It
relieves symptoms of hyperthyroidism
and anxiety, and can prevent migraine
attacks. Possible adverse effects are
typical of other beta-blocker drugs.
proprietaryA term for a drug patented
for production by one company.
proprioceptionThe body’s internal sys-
tem for collecting information about its
position and the state of contraction of
its muscles. Information from proprio-
ceptors (sensory nerve endings in the
muscles, tendons, joints, and the inner
ear) passes to the spinal cord and the
brain. The information is used to make
adjustments so that posture and bal-
ance are maintained.
proptosisA term for protrusion.
propylthiouracilA drug used to treat
hyperthyroidismor to control its symp-
toms before a thyroidectomy. Possible
adverse effects include itching, head-
ache, rash, joint pain, and decreased
production of white blood cells.
prostaglandinOne of a group of fatty
acidsthat is made naturally in the body
and acts in a similar way tohormones.
Prostaglandins cause pain and inflam-
mation in damaged tissue, protect the
lining of the stomach and duodenum
against ulceration, lower blood pressure,
and stimulate contractions in labour.
(See also prostaglandin drugs.)
prostaglandin drugsSynthetically pro-
duced prostaglandins. Dinoprostone is
used with oxytocin for induction of
labour. Gemeprost softens and helps to
dilate the cervix prior to inducing an
abortion. Alprostadil is used to treat
newborn infants awaiting surgery for
some congenital heart diseases.
prostate, cancer ofA cancerous growth
in the prostate gland, of unknown cause.
One of the most common cancers in
men, it mainly occurs in elderly men.
An enlarged prostate (see prostate, en-
larged) may cause symptoms including
difficulty in starting to pass urine, poor
urine flow, and increased frequency of
urination. Urine flow may eventually
cease altogether. When there are no uri-
nary symptoms, the first sign may be
pain in the bones from secondary cancers.
Screening tests detect blood levels of a
protein called prostate specific antigen;PROLACTIN PROSTATE, CANCER OFP