Drug acting on blood

2. (1) Drugs used to decrease clotting or
dissolve clots already present in patients
at risk for vascular occlusion.
(2) Drugs used to increase clotting in
patients with clotting deficiencies.

3. Drugs affecting blood clotting
I- Drugs decrease blood clotting (anti-thrombotic):
1. Anti-platelet drugs (prophylactic).
2. Anti-coagulants (Prevent coagulation).
3. Fibrinolytics (Dissolve clots).
II- Drugs for treatment of bleeding:
• Stop bleeding and hemorrhage (Homeostatic).
• Overcome clotting deficiencies (replacement
therapies).

4. Anti-Platelet drugs
Inhibit the aggregation of platelets.
• Clinical use : - prevents arterial thrombus.
• Side Effects: uncontrolled bleeding
• No effect on existing thrombi.
1- Aspirin
2- Abciximab
3- Clopidogrel

5. clinical uses of
Aspirin
• Preventing myocardial infarction for angina patient.
• Preventing re-infraction
• Preventing strokes
• Atherosclerosis.
• Coronary by-pass surgery.

6. Anticoagulants
• Interrupt clotting cascade at various points.
– No effect on platelets.
• Drugs:
1. Heparin & low molecular weight Heparin (LMW).
2. Warfarin.
3. Direct Thrombin Inhibitors: Lepirudin .

7. low molecular weight heparin [LMWH]
Advantage of LMWH (e.g. Enoxaparin, flaxiparin)
compared to tradional heparin:

8. • Because of its rapid effect, heparin is used when
anticoagulation is needed immediately .
• Uses: Treatment of deep vein thrombosis (DVT),
– Pulmonary embolism,
– Acute myocardial infarction MI
– During angioplasty and placement of coronary stents.
Uses of heparin

9. • Increased bleeding :
is the most common adverse effect of heparin and
related drugs.
– Prolonged use of un-fractionated heparin is
associated with osteoporosis.
• Protamine sulphate can be used as an
antidote.
Toxicity of heparin

10. Direct Thrombin Inhibitors (DTIs)
 Directly binds and inhibit thrombin.
 Unlike the heparins, these drugs inhibit both soluble
thrombin and the thrombin enmeshed within developing
clots.
 Bivalirudin and fondaparinux

11. Oral anticoagulants
• E.g. : Coumarins: - warfarin, dicoumarol.
• Structurally related to vitamin K.
• Inhibits production of active clotting factors.
• Delayed onset 8 - 12 hrs, due to existing clotting factors.
• Warfarin is used for chronic anticoagulation in all of the clinical
situations described previously for heparin, except in pregnant
women.
.

12. Side Effect of Warfarin
Severe Side effects:
Warfarin has a narrow therapeutic window.
Severe bleeding :
- Bleeding
- Chest pain or pressure.
- Skin conditions such as hives, rash or itching.
- Numbness & tingling in any part of your body.
- Painful erection lasting four hours or longer.

13. Warfarin Therapy
Bleeding
Clotting

14. Fibrinolytic drugs
Use: Enhance degradation of clots.
Exogenously administered drugs:
• Streptokinase: bacterial product, cause immune
response
• Alteplase: Genetically cloned , no immune
reaction, selective but EXPENSIVE

15. Drug preparations : to stop bleeding= hemostatic
• Systemic use :
- Aminocaproic acid
- Tranexamic acid
- Vitamin K.
• Local adsorbable drugs:
– Gelatin sponge (Gelfoam).
– Gelatin film.
– Oxidized cellulose (Oxycel).
– Micro-fibrillar collagen (Avitene).
– Thrombin.