Drugs - pharm Flashcards
What are the anticoagulant drugs for haematology?
- Heparin
- Warfarin
- DOAC
What are the antiplatlets drugs for haematology?
- Aspirin
- Clopidogrel/prasugel
How does Aspirin work?
Inhibits cyclo-oxygenase, reducing thromboxane A2 production, which is a platelet agonist released on activation
What are the adverse effects of Aspirin?
(1) Bleeding: Affects platelet function for 7–10 days, stop 7 days before elective operations, reverse with platelet transfusion if needed
(2) Blocks prostaglandin production: Can cause GI ulceration and bronchospasm
How is Aspirin administered?
PO
How do Clopidogrel and Prasugrel work?
ADP receptor antagonists
What are the adverse effects of Clopidogrel and Prasugrel?
Bleeding: Same considerations as Aspirin
How are Clopidogrel and Prasugrel administered?
PO
How does Dipyridamole work?
Phosphodiesterase inhibitor: Increases cAMP, inhibiting platelet aggregation
What are the adverse effects of Dipyridamole?
Bleeding - same as aspirin
How is Dipyridamole administered?
PO
What are the main indications for GP IIb/IIIa inhibitors (e.g., abciximab)?
Anti-platelet agents
How do GP IIb/IIIa inhibitors work?
Inhibit platelet aggregation
What are the adverse effects of GP IIb/IIIa inhibitors?
bleeding - same as aspirin
How are GP IIb/IIIa inhibitors administered?
IV
How does Heparin work?
Potentiates antithrombin (immediate effect)
Two forms: Unfractionated or low molecular weight (LMWH)
What are the adverse effects of Heparin?
Bleeding
Heparin-induced thrombocytopenia with thrombosis (HITT) – monitor FBC
Osteoporosis with long-term use
How can Heparin be reversed?
Stop Heparin (short half-life)
Protamine sulfate reverses the antithrombin effect (complete for unfractionated, partial for LMWH)
How is Heparin administered?
IV or SC
How does Warfarin work?
Inhibits vitamin K-dependent clotting factors (II, VII, IX, X, protein C, and protein S)
Why is INR important for Warfarin therapy?
INR standardizes prothrombin time reporting, correcting for thromboplastin reagent sensitivity differences
What are the adverse effects of Warfarin?
Major risk: Haemorrhage
Mild bleeding: Skin bruising, epistaxis, haematuria
Severe bleeding: Gastrointestinal, intracerebral, significant Hb drop
How can Warfarin be reversed?
(1) No action for minor elevation
(2) Omit dose
(3) Administer oral vitamin K (6-hour effect) or clotting factors (immediate effect)
How is Warfarin administered?
PO, same time daily (6 pm recommended)
What are the main indications for DOACs?
(1) Prophylaxis in elective hip and knee replacement
(2) Treatment of DVT/PE
(3) Stroke prevention in atrial fibrillation
How do DOACs work?
(1) Direct thrombin inhibitors (e.g., dabigatran)
(2) Direct activated factor X inhibitors (e.g., edoxaban, rivaroxaban, apixaban)
What are the advantages of DOACs over Warfarin?
No monitoring required
Fewer drug interactions
How are DOACs administered?
PO
At what INR level is surgery considered safe?
INR < 1.5
