200 Section 4/ Drugs Acting on Cardiovascular & Urinary SystemIt is used in burns, shock, in patients of
acute liver failure and on dialysis.
DEXTRAN
They are most commonly used plasma ex-
panders. It is polysaccharide isolated from beet
sugar which is formed by the action of
Leuconstec mesenteroides. It is available in mainly
two forms depending upon the molecular
weight. Dextran 70 (mol. wt. 70,000) available
in 6% solution and Dextran 40 (mol. wt. 40,000)
available in 10% solution. They are infused in-
travenously in the treatment of shock. Dextran
40 acts more rapidly than dextran 70. It de-
creases the blood viscosity and prevents the
sludging of RBC’s. Dextran 70 remains in cir-
culation for longer period (upto 24 hrs) and is
slowly excreted by glomerular filtration.
It is commonly used cheap plasma ex-
pander and can be stored for a longer period
of time but it may interfere with blood group-
ing and cross matching. It may trigger ana-
phylactic reaction characterized by urticaria,
bronchospasm and decrease in blood pres-
sure etc. It can also prolong bleeding time by
interfering in coagulation of blood.
DEGRADED GELATIN POLYMER –
POLYGELINE
It is a polypeptide and exerts oncotic
pressure similar to albumin. It remains in
circulation for 12 hours and is slowly ex-
creted by the kidney. It does not interfere
with blood grouping and cross matching.
It is a plasma substitute which corrects
circulatory insufficiency due to plasma/
blood volume deficiency, absolute (e.g., re-
sulting from bleeding) or relative (e.g., re-
sulting from a shift in the blood volume be-
tween the circulatory compartments).
Side effects include transient skin reac-
tions (urticaria, wheals), hypotension, tachy-
cardia, bradycardia, nausea/vomiting, dysp-
noea, a rise in temperature and/or chills may
occasionally occur. In rare cases of severe hy-
persensitivity reactions leading to shock.
If side effects occur, the infusion should
be discontinued at once. Anaphylactic reac-
tions associated with polygeline are due to
histamine release.
It is indicated in hypovolaemic shock,
loss of blood and plasma (e.g., trauma,
burns, preoperative autologous blood or
plasma donation), and for priming the heart-
lung machine. In addition, it can be used as
a vehicle for various drugs.HYDROXYETHYL STARCH
It is similar to glycogen, the starch mol-
ecule is substituted to a selected degree to
achieve a distinct plasma retention and vol-
ume effect. It improves haemodynamics,
macrocirculation, microcirculation, organ
function, oxygen supply.
After IV administration it is enzymatically
metabolised by endogenous amylase. The
smaller fragments undergo rapid glomerular
filtration. The 6% iso-oncotic infusion solution
allows precise blood volume control and leads
to an effective stabilisation of blood volume,
whereas 10% hyperoncotic infusion solution
has a greater expansive volume effect. It im-
proves plasma volume for 24 hours or more.
Adverse effects include anaphylactoid
reactions, manifesting as itching, chills, ur-
ticaria, shock and bronchospasm. In rising
doses it can influence coagulation mecha-
nism without triggering clinical haemor-
rhage.