Drugs Effecting Blood Flow Flashcards
Drugs used in thrombotic dis
- Anti-Platelet drugs (Art Thrombosis)
- Anti-fibrin drugs (Venus Throm)
- Thrombolytic drugs
Anti Platelet Drugs
Acting on TXA2
Acting on ADP
Acting on Thrombin
Acting on Gp IIb/IIIa
Drugs inhibiting TXA2
Low dose Aspirin (40-325 mg) is used as anti-platelet agent
Drugs acting on ADP receptors
-ADP receptors on platelets - P2,Y12
#P2,Y12 = #Platelet aggregation
-Irreversible antagonist
•Clopidogrel - prodrug (activated by
CYP2C19 Enz)
•Ticlopidine-X prodrug (activated by
CYP2C19 Enz)
-X -Thromobocytopenia(S/E)
•Prasugrel
- Omeprazole(C/I) #CYP2C19
(Panto,Rabo least chance)
-faster acting than Clopidogrel
S/E- Cerebral haemorrhage
-Irreversible drugs need to be stopped
at least 7 days before surgery
-Reversible antagonist
•Cangrelor- ×
•Ticagrelor -orally
Drugs acting on thrombin receptors
-Thrombin receptor on platelet is -PAR-1
(Protease Activated Receptor-1)
-#PSR-1 = #platelet aggregation
•Atopaxar -×
•Vorapaxar-Orally
Drugs actin on GP Ilb/lIla receptor
• Abciximab
•Tirofiban
•Eptifibatide
-These are the strongest acting
anti-platelet drugs
-These are injectable drugs and not
effective orally.
ANTI-FIBRIN DRUGS/ANTI COAGULANT
DRUGS
ORAL
-Vit K antagonist
•Warfarin
-Fator X#
•Rivaraxaban
•Apixaban
•Edoxaban
•Betrixaban
-Factor IIa#
•Dabigatran
INJECTABLES
-Indirect IIa#
•Unfractionated heparin
•LMWH
•Fondaparinux
-Direct IIa#
•Hirudin
•Lepirudn
•Bivalirudin
•Argatroban
•Melagatran
Vit k Antagonist
Vit K = # protein C & protein S
•Warfarin (overdose - bleeding)
-Doesn’t inhibit already active factors.
they keep on working.
-Action of warfarin like drugs is
delayed. (4-5 days action to start)
-So warfarin like drugs cannot be used
for treatment of acute thrombosis.
-They can only be given as maintenance
drugs.
- Dec anti clotting factors
=Hypercoagulation
-S/E =Dermal vascular necrosis
Purple Toe Syndrome
(early side effect, in 1-2 d after
giving Warfarin).
-It is not seen in normal ppl. Usually in
ppl with genetic deficiency of protin C.)
Warfarin Imp Info
Warfarin like drugs
Given orally
MOA :Inhibit VKOR
Slow acting (4-5 days)
Early S/E Hypercoagulation
Used mainly for maintenance
Teratogenic so avoided in pregnancy
Monitoring is required
Fetal warfarin Syndrome
•warfarin in preg = # ✓-carboxylation =
#Osteocalcin=
-warfarin embryopathy
-Fetal Warfarin Syndrome
•Features of Fetal Warfarin Syndrome:
-Microcephaly
-Hypoplasia of nasal bone
-Microphthalmia
-Telecanthus
So warfarin is avoided in 1& 3 Trimester. (risk of Vit K deficiency in the new born)
Clotting pathway
-Intrinsic pathway is measured by aPTT
(activated partial thromboplastin time)
-Extrinsic pathway is measured by PT
(Prothrombin time)
•WEPT
•HINT
Normal values
aPTT: 26-32 sec (~30sec)
PT: 12-16 sec (~15sec)
INR value is calculated as:
INR=[PT test / PT control]× ISI
Treatment of Bleeding d/t Warfarin:
1) Four Factor Complex/ Prothrombin
Factor Complex (PFC).
(factor lla, Vlla, IXa, Xa) =( DOC.)
2) Fresh Frozen Plasma (FFP)
3) Give Whole blood
Treatment of Bleeding Tendency d/t warfarin:
-means that the bleeding has not
started yet.
• VitK
( VitK is also antidote for warfarin
overdose.)
To check for bleeding tendency and risk of bleeding.
we use INR:
i. INR<5→stop warfarin
ii. 5-20→ stop warfarin
+
Give Vit. K
III.>20→ stop warfarin
+
Give FFC
Warfarin drug interactions
ENZYME INDUCERS:
•Rifampicin, CBZ
-inc the metabolism of warfarin
-becomes ineffective.
-INR value is lower.
-risk of thrombosis.
-increase the dose of warfarin.
ENZYME INHIBITORS
•Ciprofloxacin, Erythromycin:
-They # metabolism of warfarin
-INR increases.
-inc risk of bleeding.
-dec the dose of warfarin.
