DITHRANOL
D
dithranol
A drug that is used in the treatment of
the skin condition
psoriasis
.
Dithranol
is prescribed as an ointment, paste, or
cream and works by slowing the rate at
w hich skin cells multiply. This effect
can
be
boosted by ultraviolet
light
treatment (see
phototherapy
) .
Dithranol
can cause skin inflammation.
diuretic drugs
Drugs that help to remove excess water
from
the
body
by
increasing
the
amount that is lost as
urine
.
Diuretic
drugs are used in the treatment of a
variety of disorders, including
hyperten-
sion
(high blood pressure),
heart failure
,
the eye condition
glaucoma
,
nephrotic
syndrome
(a kidney disorder), and
cir-
rhosis
of the liver.
TYPES
There
are various types
of diuretic
drug, w hich differ markedly in their
speed and mode of action. Thiazide
diuretics cause a moderate increase in
urine production. Loop diuretic drugs
are fast-acting, powerful drugs that are
often used as an emergency treatment
for
heart
failure.
Potassium-sparing
diuretics are used along with thiazide
and loop diuretics, both of w hich may
cause the body to lose too much potas-
sium.
Carbonic
anhydrase
inhibitors
block the action of the enzyme carbon-
ic anhydrase, w hich affects the amount
of bicarbonate ions in the blood; these
drugs increase urine output moderately
but are effective only for short periods
of time. Osmotic diuretics are used to
maintain urine output following seri-
ous injury or major surgery.
POSSIBLE ADVERSE EFFECTS
Diuretics may cause chemical imbal-
ances in the blood. The most common
is hypokalaemia (low blood levels of
potassium). This is usually treated with
potassium supplements or potassium-
sparing diuretic drugs. A diet rich in
potassium may also be helpful. Some
diuretics raise the blood level of uric
acid, w hich increases the risk of
gout
.
Certain
diuretic
drugs
increase
the
blood glucose level, w hich may wors-
en
diabetes mellitus.
HOW DIURETICS WORK
The normal filtration process of the
kidneys (which takes place in the
tubules) removes water, salts (mainly
potassium and sodium), and waste
products from the bloodstream. Most
of the salts and water are returned to
the bloodstream, but certain amounts
are expelled from the body together
with the waste products in the urine.
Diuretics interfere with this normal
kidney action. Osmotic, loop, and
thiazide diuretics reduce the amount
of sodium and water taken backinto
the blood, thus increasing the volume
of urine. Modifying filtration in this way
reduces the blood’s water content. Less
water in the blood causes excess water
in the tissues to be expelled in urine.
the tubules to reduce the
reabsorption of water into
the bloodstream.
the middle part of the
tubules and blocksodium
and chloride reabsorption.
of the tubules to reduce the
reabsorption of sodium into
the bloodstream.
diurnal rhythms
A biological pattern that is based on a
daily cycle; also called
circadian rhythms
.
(See also
biorhythms
. )
diverticula
Small sacs or pouches that protrude
externally from the w all of a hollow
organ (such as the colon). They are
thought to be caused by pressure forc-
ing the lining of the organ though
areas of weakness in the wall. Their
presence in the walls of the intestines is
characteristic of
diverticular disease
.
diverticular disease
The presence of small protruding sacs
or pouches
called diverticula in the
intestinal wall, and the symptoms or
complications caused by them. The term
diverticulosis
signifies the presence of
diverticula in the intestine.
Diverticulitis
is
a complication produced by inflamma-
tion in one or more diverticula.
diverticulitis
Inflammation of
diverticula
(abnormal
pouches) in the wall of the intestine,
particularly in the
colon
.
Diverticulitis is
a form of
diverticular disease
and a com-
plication of
diverticulosis
.
SYMPTOMS AND COMPLICATIONS
The symptoms include fever, abdomi-
nal pain, vom iting, and rigidity of the
abdomen. Intestinal haemorrhage may
cause bleeding from the rectum.
Diverticula may perforate, or absces-
ses may form in the tissue around the
colon, leading to
peritonitis
(inflamma-
tion of the lining of the abdomen).
Other complications include intestinal
bleeding, narrowing in the intestine, or
a
fistula
(an abnormal channel between
one part of the intestine and another).
TREATMENT
Diverticulitis usually subsides with bed
rest and
antibiotics
.
In severe cases, a
liquid diet or
intravenous infusion
may
be required. Surgery may be needed,
in w hich the diseased section of the
intestine is removed and the remaining
sections are then joined back together.
Some patients are given a temporary
colostomy
(an operation in w hich part
of the colon is attached to the abdomi-
nal w all to form an opening for the
discharge of faeces).
diverticulosis
A form of
diverticular disease
in w hich
diverticula
(abnormal pouches) exist in
the w all of the intestine, particularly in
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