Blood affecting drugs

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HEMOSTASIS

HEMOSTASIS

It is the arrest of blood loss from
damaged vessels and is essential to
life

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HEMOSTASIS

HEMOSTASIS

Physical trauma to the vascular
system causes

vasoconstriction

and

initiates series of interactions
between

platelets

,

endothelial cells

and

the

coagulation cascade

.

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Formation of a hemostatic

Formation of a hemostatic

plug

plug

1.

Damage to vessel exposes

collagen of sub-endothelium

2.

Platelet adhesion and release of

granules

3.

Platelet aggregation and activation

factors in plasma

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THROMBOSIS

THROMBOSIS

It is a pathological condition resulting
from inappropriate activation of
haemostatic mechanisms.

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VENOUS THROMBOSIS

VENOUS THROMBOSIS

Usually associated with stasis of
blood;
Venous thrombus has a small platelet
component and a large component of
fibrin

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ARTERIAL THROMBOSIS

ARTERIAL THROMBOSIS

Usually associated with
atherosclerosis;
Arterial thrombus has a large platelet
component

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Drugs affect haemostasis

Drugs affect haemostasis

and thrombosis

and thrombosis

By affecting:

Blood coagulation (fibrin formation)

Platelet function

Fibrin removal (fibrynolysis)

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DRUG AFFECTING BLOOD

PLATELET INHIBITORS

ANTICOAGULANTS

THROMBOLYTIC AGENTS

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DRUG AFFECTING BLOOD

PLATELET INHIBITORS

Aspirin

Clopidogrel

Ticlopidine

Glycoprotein IIb/IIIa

Receptor Antagonists

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ANTIPLATELET DRUGS –

ANTIPLATELET DRUGS –

ASPIRIN

ASPIRIN

Inactivates constitutive form of

cyclooxygenase

(COX-1), the key enzyme

which takes part in synthesis among other

thromboxane

A

2

(TXA

2

) in platelet from

arachidonic acid

TXA

2

promotes aggregation

Suppression of platelet aggregation last to

the end of platelet’s life (7-10 days)

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ANTIPLATELET DRUGS –

ANTIPLATELET DRUGS –

ASPIRIN

ASPIRIN

Daily recommended dose is 75-100mg

Clinical uses:

prophylactic treatment of transient

ischemic atacks (TIA)

Reduction of the incidence of myocardial

infarction

decrease mortality in postmyocardial

infarction patients

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ANTIPLATELET DRUGS –

ANTIPLATELET DRUGS –

ASPIRIN

ASPIRIN

Unwanted effects:

Bleeding time is prolonged

Increased incidence of hemorrhagic

stroke

Increased incidence of gastrointestinal

bleeding (ulcer)

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ANTIPLATELET DRUGS –

ANTIPLATELET DRUGS –

TICLOPIDINE

TICLOPIDINE

It inhibits ADP-dependent aggregation of the

platelet

Decreases the incidence of thrombotic stroke

Clinical uses:

For patients who cannot tolerate Aspirin

Unwanted effects:

Prolonged bleedings

Neutropenia

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ANTIPLATELET DRUGS –

ANTIPLATELET DRUGS –

CLOPIDOGREL

CLOPIDOGREL

It is analog of ticlopidine

Also inhibits ADP-induced aggregation

It is more effective than Aspirin

It is recommended for patients before PTCA

The main unwanted effect is bleeding

It can inhibit cytochrom P-450 so it may interfere

with metabolism of other drugs (warfarin or
fluvastatin)

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ANTIPLATELET DRUGS –

ANTIPLATELET DRUGS –

antagonists of GP IIb/IIIa

antagonists of GP IIb/IIIa

receptors

receptors

ABCIXIMAB a monoconal antibody

TIROFIBAN oligopeptid

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ANTIPLATELET DRUGS –

ANTIPLATELET DRUGS –

antagonists of GP IIb/IIIa

antagonists of GP IIb/IIIa

receptors

receptors

They inhibit all pathways of platelet

activation

By binding to GP IIb/IIIa receptor they

block the binding of fibrynogen and other
factor and aggregation does not occur

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ANTIPLATELET DRUGS –

ANTIPLATELET DRUGS –

antagonists of GP IIb/IIIa

antagonists of GP IIb/IIIa

receptors

receptors

They are used intravenously for single

administration

CLINICAL USES:

in high-risk patients undergoing coronary angioplasty

to reduce the risk of restenosis

UNWANTED EFFECTS:

potencial of bleeding

immunogenicity

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DRUG AFFECTING BLOOD

ANTICOAGULANTS

HEPARIN

ENOXAPRIN

VITAMIN K

ANTAGONISTS

WARFARIN

ACENOCOUMAROL

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CLINICAL USE OF

CLINICAL USE OF

ANTICOAGULANTS

ANTICOAGULANTS

They are used for prevention of:

Deep vein thrombosis

Extension of established deep vein
thrombosis or recurrence of
pulmonary embolus

Thrombosis and embolisation in
patients with atrial fibrillation

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CLINICAL USE OF

CLINICAL USE OF

ANTICOAGULANTS

ANTICOAGULANTS

Thrombosis on prosthetic heart valves

Cardiac events in patients with
unstable coronary syndromes

Cotting in extracorporeal circulations
(haemodialysis or bypass surgery)

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HEPARIN

HEPARIN

It is not a single substance but a family of

mucopolysaccharides

It is present with histamine in the

granules of mast cells

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HEPARIN

HEPARIN

Inhibits coagulation by activating

antithrombin III, which inhibits thrombin
(IIa) , factor Xa and other serine proteases
by binding to the active site

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HEPARIN

HEPARIN

Is given intravenously or subcutaneously

The activated partial thromboplastin time

(APTT) must be measured
(targed range 1,5-2,5 times control)

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HEPARIN

HEPARIN

ADVERSE EFFECTS

Hemorrhage

Hypersensitivity reactions: chills, fever

and even anaphylactic shock

Thrombocytopenia (after 8-10 days of

treatment)

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ENOXAPRIN

ENOXAPRIN

It is one of low-molecular-weight heparins
(LMWHs);
It is fractionated heparin

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ENOXAPRIN

ENOXAPRIN

Increase the action of antithrombin III on

factor Xa

Does not act on thrombin

Has a longer elimination half-time than

heparin

Does not prolong the APTT

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ORAL ANTICOAGULANTS -

ORAL ANTICOAGULANTS -

WARFARIN

WARFARIN

Warfarin has structual similarity to

vitamin K

Inhibits activation of factors II, VII, IX, X,

which are depend on present of vitamin K

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ORAL ANTICOAGULANTS -

ORAL ANTICOAGULANTS -

WARFARIN

WARFARIN

Pharmacological effect is delayed, it can

occur about 48 hours after first
administration

The effect must be monitored by

measuring INR (target range 2-3)

Dose are given indyvidualised according

to INR

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ORAL ANTICOAGULANTS -

ORAL ANTICOAGULANTS -

WARFARIN

WARFARIN

ADVERSE EFFECTS

Hemorrhage and bleeding

Cause abortion

It is teratogenic agent

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WARFARIN - interactions

Increased effect

Amiodarone

Ciprofloxacin

Metronidazole

Some of NSAIDs

Sulfonamides

Decreased effect

Vitamin K

Barbiturates

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DRUG AFFECTING BLOOD

THROMBOLYTIC AGENTS

ALTEPLASE

STREPTOKINASE

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THROMBOLYTIC DRUGS

THROMBOLYTIC DRUGS

CLINICAL USES:

Acute myocardial infarction within 12
hours of onset
THE EARLIER THE BETTER!

Acute thrombotic stroke within 3
hours of onset (in selected patients)

Acute arterial thromboembolism

Clearing arterial shunts and cannulae

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THROMBOLYTIC DRUGS

THROMBOLYTIC DRUGS

STREPTOKINASE

Is a protein extracted from culture of
streptococci

Activates free plasminogen to convert
to plasmin, which in turn cleaves
fibrin, thus lysing thrombi

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THROMBOLYTIC DRUGS

THROMBOLYTIC DRUGS

STREPTOKINASE

ADVERSE EFFECTS

Bleeding disorders

Hypersensivity – rashes, fever,
anaphylactic shock

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THROMBOLYTIC DRUGS

THROMBOLYTIC DRUGS

STREPTOKINASE

Drug does not act in patients who
have circulating antibodies against
streptokinase (in case streptococcal
infection);
they may neutralize its fibrynolytic
effect

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THROMBOLYTIC DRUGS

THROMBOLYTIC DRUGS

Alteplase

Known as tissue-type plasminogen

Known as tissue-type plasminogen

activator (tPA)

activator (tPA)

Is a serine protease from cultured
human mellanoma cells

Activates only plasminogen bound to
fibrin in a thrombus or a hemostatic
plug („fibrin selective”)

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THROMBOLYTIC DRUGS

THROMBOLYTIC DRUGS

Alteplase (tPA)

ADVERSE EFFECTS

ADVERSE EFFECTS

BLEEDING complication
(gastrointestinal and cerebral
hemorrhages)


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