Pharmacology for Dentistry

246 Section 6/ Drug Acting on Blood

Adverse effects include fever, allergic
reactions, bleeding from different sites, rarely
anaphylaxis, arrhythmias, bronchospasm.

It is indicated in acute myocardial infarction,
pulmonary embolism, deep vein thrombosis,
arterial thrombosis, acute thrombosis of central
retinal vessels, extensive coronary emboli and
severe iliofemoral thrombophlebitis.

UROKINASE

It is obtained from cultures of human renal
cells in tissue culture and it is a proteolytic
enzyme. It activates plasminogen directly.
Plasmin acts on fibrin and fibrinolysis occurs.
It is non antigenic.

Adverse effects include drug fever and
haemorrhage.

It is used for myocardial infarction, for
venous thrombosis and pulmonary embolism.

ALTEPLASE

Also known as recombinant tissue
Plasminogen Activator (rt-PA). It is produced
by recombinant DNA technology from
human tissue culture. It specifically activates
plasminogen bound to the fibrin clot. This
minimises the risk of systemic bleeding.

It is non antigenic and has a plasma t½
of 4-8 min.

Adverse effects are nausea, fever, mild
hypotension, rash, pruritus and localised
bleeding.

It is used in lysis of suspected occlusive
coronary artery thrombi associated with
evolving MI in adults.

PLATELET INHIBITING DRUGS

These drugs interfere with platelet function
and may be useful in prophylaxis of

thromboembolic disorders. Thromboxane

A 2 (TXA 2 ) from platelets promote and

prostacyclin (PGI 2 ) from vessel wall inhibit

platelet aggregation.

ABCIXIMAB

It binds to the intact glycoprotein

IIb/IIIa receptor of human platelets,

which is a member of the integrin family

of adhesion receptors and the major

platelet surface receptor involved in

platelet aggregation. The drug inhibits

platelet aggregation by preventing the

binding of fibrinogen, von Willebrand

factor and other adhesive molecules to

GP IIb/IIIa receptor sites on activated

platelets.

Adverse effects include bleeding, thrombo-

cytopenia, human antichimeric antibody deve-

lopment, atrial fibrillation/flutter, complete AV

block, palpitation, SVT, constipation, ileus,

abnormal thinking, dizziness.

It is indicated for platelet aggregation

inhibition as adjunct to percutaneous

transluminal coronary angioplasty or

atherectomy (PTCA).

ASPIRIN

In small doses aspirin inactivates irre-

versibly platelet enzyme cyclooxygenase,

hence thromboxane A 2 is not synthesised.

The effect of enzyme inactivation lasts till

the life of platelet.

It is indicated in prophylaxis in cases of

increased risk of blood clotting, myocardial

infarction, coronary bypass, transluminal

angioplasty, stroke, transient ischaemic

attack and unstable angina.