AF Flashcards
What is atrial fibrillation and complications
- An irregular, often rapid heart rate that commonly causes poor blood flow
- People with atrial fibrillation are at increased risk of having a stroke. In extreme cases, atrial fibrillation can also lead to heart failure.
Signs and symptoms of AF
- heart palpatations
- Increased and irregular HR
- SOB
- dizzy
- chest pain
Rationale for drug use
AF
reduce symptoms and minimise morbidity by slowing ventricular rate (rate control) and/or restoring and maintaining sinus rhythm (rhythm control)
prevent stroke.
Drugs for AF treatment
- Beta blockers (Metoprolol or atenolol) are suggested as first line therapy for rate control
* Warfarin
* Heparin
* Dabigatran
* Rivaroxaban
* Apixaban
Stroke risk assessment (CHA2DS2-VA) for non-valvular AF and anticoagulant treatment options
Suffix:
Beta-blocker
lol
Drug class
lol
Beta-blockers
Indication
Beta-blocker
Hypertension
Angina
Tachyarrhythmias
MI
Chronic heart failure with reduced ejection fraction as part of standard treatment
Prevention of migraine
MOA
Beta-blocker
Competitively block beta receptors in heart, peripheral vasculature, bronchi, pancreas, uterus, kidney, brain and liver.
Beta-blockers reduce heart rate, BP and cardiac contractility; also depress sinus node rate and slow conduction through the atrioventricular (AV) node, and prolong atrial refractory periods.
Precautions / adverse effects
Beta-blockers
Shock (cardiogenic and hypovolaemic)—contraindicated.
Hyperthyroidism—beta-blockers may mask clinical signs, eg tachycardia.
Phaeochromocytoma—beta-blockers may aggravate hypertension; an alpha-blocker should be given first.
History of anaphylactic reactions—beta-blockers may reduce the response to usual doses of adrenaline (epinephrine) for anaphylaxis.
Myasthenic symptoms—may worsen.
CARDIACContraindicated in bradycardia (45–50 beats/minute), second‑ or third-degree AV block, sick sinus syndrome (without pacemaker), severe hypotension or uncontrolled heart failure.
Respiratory contraindicated in asthma, alpha 1 selective drugs may be used in controlled asthma and COPD
Myasthenic symptoms (muscle weakness)
Adverse effects
Beta-blockers
- bradycardia,
- hypotension,
- orthostatic hypotension
- bronchospasm,
- dyspnoea,
- fatigue, dizziness
- Mask Hypoglycemia
Can mask signs of hypoglycemia in diabetics
Counselling / practice points
Beta-blockers
Counselling
This medicine may cause dizziness or tiredness
Do not stop taking this medicine suddenly
Practice points
beta-blockers are not usually recommended first line for uncomplicated essential hypertension; they are associated with reduced protection against stroke in the elderly
**when stopping treatment, reduce dosage gradually
Drug class and indication
Atenolol
Beta-blocker
Hypertension
Angina
Tachyarrhythmias
MI
Drug class and Indication
Metoprolol
Beta-blocker
Hypertension
Angina
Tachyarrhythmias
MI
Prevention of migraine
Chronic heart failure with reduced ejection fraction as part of standard treatment
Drug class
Warfarin
Anticoagulant
MOA
Warfarin
Vitamin K antagonist; inhibits synthesis of vitamin K-dependent clotting factors (II, VII, IX, X) and the antithrombotic factors protein C and protein S.
Indication
Warfarin
- Prevention and treatment of VTE
- Prevention of thromboembolism in patients with prosthetic heart valves
- Prevention of stroke in patients with previous MI and increased embolic risk
- AF and a high risk of stroke or systemic embolism
Precautions
Warfarin
- Alcoholism—contraindicated.
- Compliance likely to be poor—avoid unless administration is supervised.
- Protein C or protein S deficiency—increases risk of skin necrosis.
- Risk of bleeding
Adverse effects
Warfarin
bleeding
Counselling
Warfarin
- Always take the same brand of tablets.
- Take tablets at about the same time every day
- Regular INR blood tests
- Stable vitamin K intake - warfarin affected by vitamin K
Practice points
Warfarin
- the different brands have not been shown to be bioequivalent and should not be interchanged
- warfarin has a narrow therapeutic range; many drugs interact with warfarin and may decrease its efficacy or increase the risk of bleeding; it is prudent to monitor the INR when changing drug treatment
Advantages of NOACs over Warfarin
- Lower rates of intercranial bleeds and strokes
- No routine lab monitoring
- Fewer drug interactions
- Fewer food interactions
Disadvantages of NOACs over Warfarin
- Higher cost
- lack of availablity of reversal agent
- Increased risk of GI bleed
- Higher rate of VTE with poor compliance
- No clear efficacy in cancer patients
Drug interactions
Warfarin
EVERYTHING!!!
aspirin + warfarin
Combination increases risk of bleeding (as well as antiplatelet effect, aspirin causes GI bleeding and doses of 2–4 g daily have a direct hypoprothrombinaemic effect); avoid combination (except low-dose aspirin in selected patients at high risk for thromboembolism where close monitoring is required).
corticosteroids + warfarin
Corticosteroids may increase warfarin’s anticoagulant effect, increasing the risk of bleeding; monitor INR and decrease warfarin dose if necessary.
fibrates + warfarin
Fibrates may increase warfarin’s anticoagulant effect and risk of bleeding; monitor INR and decrease warfarin dose if necessary.
flucloxacillin + warfarin
Flucloxacillin may decrease warfarin’s anticoagulant effect; monitor INR within the first 3 days of flucloxacillin treatment and increase warfarin dose if necessary.
NSAIDs + warfarin
All NSAIDs (including selective COX‑2 inhibitors) increase the risk of serious GI bleeding. Nonselective agents (antiplatelet effect) and selective COX‑2 inhibitors (may increase INR) may further increase the risk of bleeding; avoid combination if possible or monitor regularly (INR and clinically). Combination with ketorolac is contraindicated.
SSRIs + warfarin
SSRIs may increase anticoagulant effect and risk of bleeding; monitor INR and decrease warfarin dose as needed.
St John’s wort + warfarin
St John’s wort increases metabolism of warfarin, decreasing its anticoagulant effect; avoid combination.
statins + warfarin
Fluvastatin, rosuvastatin and simvastatin may increase warfarin’s anticoagulant effect, increasing the risk of bleeding; consider using atorvastatin or pravastatin (do not appear to interact with warfarin) or decrease the warfarin dose according to INR.
tetracyclines + warfarin
Tetracyclines may increase warfarin’s anticoagulant effect, occasionally causing bleeding; monitor INR within the first 3 days of tetracycline treatment and decrease warfarin dose if necessary.
vitamin K + warfarin
Vitamin K decreases warfarin’s anticoagulant effect by increasing synthesis of blood clotting factors; patients should keep their dietary vitamin K intake constant. Vitamin K is used to reverse bleeding caused by excessive anticoagulation.
Generic drug names
Factor Xa inhibitors / NOAC
NOAC = Novel oral anticoagulants
Apixaban
Fondaparinux
Rivaroxaban
“aban” Suffix
Factor Xa inhibitors / NOAC
NOAC = Novel oral anticoagulants
Suffix
Factor Xa inhibitors / NOAC
NOAC = Novel oral anticoagulants
“aban”
MOA
Factor Xa inhibitors / NOAC
NOAC = Novel oral anticoagulants
Selectively inhibit factor Xa, blocking thrombin production, conversion of fibrinogen to fibrin, and thrombus development.
What does thrombin do?
thrombin is in blood and lumps together to form clumps
Precautions
Factor Xa inhibitors / NOAC
NOAC = Novel oral anticoagulants
Risk of bleeding
Precautions and adverse effect
Anticoagulants
Risk of bleeding
Adverse effects
Factor Xa inhibitors / NOAC
NOAC = Novel oral anticoagulants
bleeding, signs of bleeding (eg anaemia)
Counselling
Factor Xa inhibitors / NOAC
NOAC = Novel oral anticoagulants
Take oral meds at the same time everyday
Practice points
Factor Xa inhibitors / NOAC
NOAC = Novel oral anticoagulants
regular renal function monitoring
notify dr if bleeding
Drug class and indications
Apixaban
NOAC - Factor Xa inhibitor
* Non-valvular AF and a high risk of stroke or systemic embolism
* Prevention of VTE
* Treatment of acute VTE
NOAC = Novel oral anticoagulants
Drug class and indication
Fondaparinux
NOAC - Factor Xa inhibitor
* Prevention of VTE
* Treatment of VTE
* Treatment of unstable angina or non-STEMI
* Treatment of STEMI
NOAC = Novel oral anticoagulants
Drug class and indication
Rivaroxaban
NOAC - Factor Xa inhibitor
* Prevention of VTE
* Treatment of acute VTE
* Non-valvular AF and a high risk of stroke or systemic embolism
* Stable coronary artery disease (CAD) or peripheral artery disease (PAD); use with aspirin
NOAC = Novel oral anticoagulants
Drug interactions
Anticoagulants
Avoid drugs that increase risk of bleeding