Page 596 - TNFlipTest

H56 Hematology
Common Medications
Toronto Notes 2019
Common Medications
Antiplatelet Therapy
• seeFigure12a,PlateletActivationCascade,H26
ACTIVATED PLATELET
Adenosine
A2R AC
ATP
cAMP
Aggrenox
PDE
AMP
ACTIVATED PLATELET
Aspirin
Adhesive proteins Prothrombotic factors Proinflammatory factors Platelet agonists
Remarks
Indicated for stroke/MI prophylaxis Reduce incidence of recurrent MI Decrease mortality in post-MI patients Contraindicated in patients with GI ulcers
COX1
Table 40. Antiplatelet Therapy
Prasugrel (Effient®)
AC = adenylyl cyclase PDE = phosphodiesterase
GP IIb/IIIa inhibitors
Figure 17. Mechanisms of action of antiplatelet therapy
Clopidogrel Ticlopidine Prasugrel
ACTIVATION
DEGRANULATION
α δ
Aspirin® (ASA)
Aggrenox® (ASA + Dipyridamole)
Clopidogrel (Plavix®)
Mechanism of Action
Irreversibly acetylates COX, inhibiting TXA2 synthesis, thus inhibiting platelet aggregation
Dipyridamole increases intracellular cAMP levels, which inhibits TXA2 synthesis, leading to decreased platelet aggregation
Irreversibility inhibit ADP binding to platelets, thus decreased platelet aggregation
Same as clopidogrel
Dose/Route of Administration
Single loading 200-300 mg PO, followed by dose of 75-100 mg PO daily
1 capsule PO bid
75-300 mg PO daily
5-10 mg PO daily
Onset/Peak/ Duration
Onset: 5-30 min Peak: 0.25-3 h Duration: 3-6 h
Peak: 75 min
Onset: 2 h Peak: 1 h
Onset: 30 min
Specific Side Effects
GI ulcer/bleeding Tinnitus Bronchospam Angioedema Reye’s syndrome in pediatric patients
H/A
Dyspepsia
N/V
Abdominal pain Cardiac failure Hemorrhoids
URI
Chest pain
H/A
Flu-like syndrome Depression
UTI
GI hemorrhage Pancytopenia May cause TTP
Dizziness H/A Nervousness Blurry vision
More effective than ASA in secondary prevention of stroke Dipyridamole potentiates antiplatelet action of ASA
Prevention of cardiovascular events in high-risk patients
Clopidogrel is a prodrug requiring two-step activation to active metabolite CYP2C19 poor metabolizers have diminished response to clopidrogrel Caution with hepatic/renal impairment
Alternative to clopidogrel for prevention of cardiovascular events in high-risk patients
Higher potency compared to clopidogrel
No significant drug-drug interaction, although more data is required
ADP
Collagen Epinephrine Serotonin Thrombin
TXA2
P2YR GP IIb/IIIa R
TXA2R
© Madeline Spacher 2016 after Stephania Spano 2012