ANTICOAGULANTS Flashcards
Which drugs are LMWHs?
enoxaparin, dalteparin, tinzaparin fondaprinux
How do LMWH work?
Enhance antithrombin activity - block clotting factors 2a and 10a and disrupt the clotting cascade
ADRs of LMWH
- haemorrhage
- bruising
- hyperkalaemia (inhibits aldosterone secretion)
When are LMWH used?
- Primary prevention of VTE
- Rx alongside warfarin to treat VTE
- in ACS alongside an antiplt (clopidogrel) to maintain vascularisation
Interactions of LMWH
Synergistic effect with other antiplts and anticoagulants
Who should they be used with caution in?
- uncontrolled hypertension
- STOP before surgery
Renal impairment and LMWH
LMWH and fondaparinux accumulate in renal impairment - use unfractionated heparin instead
What information should be given to patients RE LMWH?
They have a greater risk of bleeding, so to avoid contact sports/activities that may increase their risk of bleeding
LMWH and warfarin
LMWH = used as a bridging anticoagulant at the tart of warfarin therapy until INR is within normal range
Warfarin initially has a procoagulatory effect
LMWH contraindications
Active bleeding
Recent surgery
Peptic ulcers
Thrombocytopenia
What type of drug is dabigatran?
Direct thrombin inhibitor
Indications for warfarin use
- VTE (use with heparin initially)
2. Prevention of embolism in AF and prosthetic heart valves
How does warfarin work?
Inhibits synthesis of Vit K dependent clotting factors (2, 7, 9, 10)
ADRs of warfarin
Bleeding (esp. following minor injury/from ulcers)
Spontaneous bleeding - epistaxis, retroperitoneal haemorrhage
Contraindications of warfarin
Hepatic impairment/liver disease
Pregnancy
Pts at immediate risk of haemorrhage - e.g. trauma/surgery
Drug interactions of warfarin (inducers/inhibitors)
Inducers - phenytoin, carbemazepine, rifampicin
Inhibitors - ciprofloxacin, macrolides (erythromycin), fluconazole
Administration instructions for warfarin and why
INR test in the morning and warfarin taken in evening (6pm) as it makes dosage changes easier
What should patients know about warfarin?
Regular blood tests for INR - record in Yellow Book
Risk of bleeding vs clots
Influence of alcohol/food/drugs on warfarin
Monitoring requirements of warfarin
INR monitored daily
STOPPED before surgery
