Drugs Affecting Blood

1. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
Drugs affecting bloodDrugs affecting blood
• They are used to treat thrombosisThey are used to treat thrombosis
bleeding and anaemia.bleeding and anaemia.
• Vascular trauma :Vascular trauma :
-punctures or cuts lead to the formation-punctures or cuts lead to the formation
of a platelets-fibrin plug.of a platelets-fibrin plug.
-Clot formation = platelet activation-Clot formation = platelet activation
aggregation thrombin fibrinaggregation thrombin fibrin
clot .clot .
-Inactive platelets respond to vascular-Inactive platelets respond to vascular
trauma by adhesion to the site of injury.trauma by adhesion to the site of injury.

2. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
Con.Con.
-Stimulated coagulation cascade leads to the-Stimulated coagulation cascade leads to the
increase of thrombin level and hence, fibrinogenincrease of thrombin level and hence, fibrinogen
strands forming the hemostatic plug.strands forming the hemostatic plug.
- Both thrombi and emboli occlude the bloodBoth thrombi and emboli occlude the blood
vessels and decrease oxygen and nutrients invessels and decrease oxygen and nutrients in
tissues.tissues.
- Arterial thrombosis may lead to atheroscelorosis .Arterial thrombosis may lead to atheroscelorosis .
- Defects in normal defense hemostaticDefects in normal defense hemostatic
mechanisms may lead to blood stasis or impropermechanisms may lead to blood stasis or improper
coagulation cascade and hence ,venouscoagulation cascade and hence ,venous
thrombosis.thrombosis.

3. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
ChemicalChemical signalssignals that oppose-plateletthat oppose-platelet
activation:activation:
• Increased prostacyclin levels.Increased prostacyclin levels.
• Decreased plasma levels of thrombin andDecreased plasma levels of thrombin and
thromboxanes .thromboxanes .

4. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
ChemicalChemical signalssignals that promote-plateletthat promote-platelet
aggregation:aggregation:
• Decreased prosacyclin levels .Decreased prosacyclin levels .
• Exposed collagen may lead to plateletExposed collagen may lead to platelet
release reaction.release reaction.
• Increased synthesis of thromboxanes .Increased synthesis of thromboxanes .
• Both types of signals balance whetherBoth types of signals balance whether
platelet are stimulated or stayedplatelet are stimulated or stayed
quiescent.quiescent.

5. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
Platelet aggregation inhibitorsPlatelet aggregation inhibitors
• They act by decreasing the formation orThey act by decreasing the formation or
the action of signals that promote plateletthe action of signals that promote platelet
aggrgation.This is used in the treatment ofaggrgation.This is used in the treatment of
cardiovascular diseases , maintenance ofcardiovascular diseases , maintenance of
vascular grafts, arterial potency andvascular grafts, arterial potency and
adjustment to thrombolytic therapy inadjustment to thrombolytic therapy in
myocardial infarction e.g. aspirin.myocardial infarction e.g. aspirin.

6. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
AnticoagulantsAnticoagulants
• Heparin : It is an injectable,rapidly actingHeparin : It is an injectable,rapidly acting
macromolecule that is complexed withmacromolecule that is complexed with
histamines in mast cells. It is extractedhistamines in mast cells. It is extracted
from porcine intestine or bovine lung.from porcine intestine or bovine lung.
• Enoxaprin is a low molecular weightEnoxaprin is a low molecular weight
heparin .heparin .
• Heparin acts by enhancing inactiveHeparin acts by enhancing inactive
clotting factorsclotting factors

7. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
Con.Con.
• Therapeutic uses :Therapeutic uses :
-It acts on thrombi by preventing fibrin-It acts on thrombi by preventing fibrin
formation.formation.
- Enoxaprin prevent deep vein thrombosis- Enoxaprin prevent deep vein thrombosis
following hip replacement.following hip replacement.
• Phamacokinetics :It is given by deep S/C or I/MPhamacokinetics :It is given by deep S/C or I/M
or in a bolus I/V followed by continuousor in a bolus I/V followed by continuous
infusion.It binds to plasma proteins andinfusion.It binds to plasma proteins and
reticuloendothelial cells and by depolymerizationreticuloendothelial cells and by depolymerization
inactivated to be excreted in urine .inactivated to be excreted in urine .

8. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
WarfarinWarfarin
• Coumarin anticoagulnt = warfarin +Coumarin anticoagulnt = warfarin +
dicumarol work by their ability todicumarol work by their ability to
antagonize the co-factor functions ofantagonize the co-factor functions of
vitamin K.vitamin K.
• It is a former rodenticide that can not beIt is a former rodenticide that can not be
monitored to keep the prothrombin time atmonitored to keep the prothrombin time at
1.5 to 2.5 .1.5 to 2.5 .

9. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
Con.Con.
• Mechanism of action :These vitamin KMechanism of action :These vitamin K
cofactors including factors II,VII,IX and X,cofactors including factors II,VII,IX and X,
undergo vitamin K-dependant post-undergo vitamin K-dependant post-
translational modification. A number oftranslational modification. A number of
their glutamine acid residues aretheir glutamine acid residues are
carboxylated to formcarboxylated to form γγ--carboxyglutamiccarboxyglutamic
acid residues that bind calcium ions andacid residues that bind calcium ions and
are essential for interaction with cellare essential for interaction with cell
membranes. Warfarin or dicumarol lead tomembranes. Warfarin or dicumarol lead to
inactive clotting factors.inactive clotting factors.

10. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
Con.Con.
• Pharmacokinetics :Pharmacokinetics :
* Sodium salts of warfarin if given orally* Sodium salts of warfarin if given orally
are completely absorbed and bound toare completely absorbed and bound to
plasma proteins ,hence they can notplasma proteins ,hence they can not
diffuse to cerebrospinal fluid ,urine anddiffuse to cerebrospinal fluid ,urine and
breast milk ,but can rapidly cross placentalbreast milk ,but can rapidly cross placental
barreir and glucronidate to urine and stool.barreir and glucronidate to urine and stool.

11. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
Trombolytic drugsTrombolytic drugs
• Plasminogen is activated systemically byPlasminogen is activated systemically by
streptokinases and urokinases and via tissue-streptokinases and urokinases and via tissue-
uptake by alteplase to give plasmin and finallyuptake by alteplase to give plasmin and finally
fibrin and fibrin degradation products.fibrin and fibrin degradation products.
• They all act to convert plasminogen to plasmin ,They all act to convert plasminogen to plasmin ,
cleaves fibrin leading to lysed thrombin. This cancleaves fibrin leading to lysed thrombin. This can
be achieved if initiated early after the clotbe achieved if initiated early after the clot
formation.formation.
• To avoid platelet thrombosis and aggregability useTo avoid platelet thrombosis and aggregability use
antiplatelet drugs e.g. aspirin or antithromboticsantiplatelet drugs e.g. aspirin or antithrombotics
e.g. heparin.e.g. heparin.

12. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
Con.Con.
• They should be given intracoronary toThey should be given intracoronary to
treat myocardial infarction .treat myocardial infarction .
• They are used to treat deep veinThey are used to treat deep vein
thrombosis, serious pulmonary embolism ,thrombosis, serious pulmonary embolism ,
acute myocardial infarction , peripheralacute myocardial infarction , peripheral
arterial thrombosis & emboli and forarterial thrombosis & emboli and for
unclotted catherters and shunts.unclotted catherters and shunts.
• These agents do not distinguish betweenThese agents do not distinguish between
thrombi and fibrin.thrombi and fibrin.

13. 04/22/1504/22/15 Dr. Medani ,A.B.2006Dr. Medani ,A.B.2006
Drugs used to treat bleedingDrugs used to treat bleeding
• In fibrinolytic status use aminocaproic acidIn fibrinolytic status use aminocaproic acid
or transexamic acid.or transexamic acid.
• Antagonize heparin by protamine sulfate.Antagonize heparin by protamine sulfate.
• Stop bleeding problems by vitamin KStop bleeding problems by vitamin K11..
• Anaemia is treated with iron ,folic acidAnaemia is treated with iron ,folic acid
,cyalocobalamin and erythrobiotin.,cyalocobalamin and erythrobiotin.
• Sickle cell anaemia is treated withSickle cell anaemia is treated with
hydroxyurea .hydroxyurea .