Anti-platelets (exam 2)

Question 1

Aspirin

Answer 1

-inhibits prostaglandin synthesis (COX 1/2)
-blocks thromboxane A2 synthesis
USES: TIAs, stroke, MI, unstable angina, post-op vascular surgeries
TOX: risk of hemorrhage, GI ulcer, allergic rxn

Question 2

Dipyridamole/Cilostazol

Answer 2

• inhibits phosphodiesterase, thus increasing cAMP, which block ADP release
• may inhibit TXA2; may block adenosine reuptake
• USES: may not work any better than aspirin, same indications though
• TOX: GIT problems, dizzy, headache

Question 3

Ticlopidine (Ticlid)

Answer 3

• ADP receptor blocker
• prevents ADP stimulated aggregation
• TOX: bleeding, GI upset/ulcer (less than ASA), agranulocytosis (RARE)

Question 4

Clopidogrel (Plavix)

Answer 4

• Blocks ADP receptors
• blocks ADP stimulated aggregation.
• Possible drug interaction with proton pump inhibitors; decreases the effectiveness of both because clopidogrel must be activated by P-450 metabolism.
• TOX: similar to Ticlid: bleeding, GI upset/ulcer (less than ASA), but much less likely to cause agranulocytosis

Question 5

Tirofiban (Aggrastat)

Answer 5

-Glycoprotein 2b/3a receptor antagonist
-Binds to platelet glycoprotein IIb/IIIa receptors thus inhibiting platelet aggregation.
TOX: In addition to bleeding; bradycardia, pelvic pain, edema, syncope

Question 6

Abciximab (ReoPro)

Answer 6

-Glycoprotein 2b/3a receptor antagonist
-monoclonal antibody to the GPIIb/IIIa binding proteins
-immunologic response only allows one administration
-blocks the binding of fibrinogen and additional platelet aggregation
TOX: in addition to bleeding; back pain, hypotension, nausea

Question 7

Epoprostenol (Flolan)

Answer 7

• Prostanoid receptor agonist
• prostacyclin analog (PGI2) that binds to normal prostacyclin binding site on platelet, prevents activation/aggregation cascade
• dilates blood vessels
• USES: pulmonary hypertension (via IV infusion, thus short half life)
• TOX: flushing, hypotension, headache