Cardiovascular- HIGH Flashcards
When is amiodarone initiated for patients?
ONLY under specialist supervision, usually in secondary care (HIGH RISK DRUG)
What is amiodarone indicated for?
How does it act on the heart?
Arrhythmias- where past treatment has failed
Acts on both supraventricular and ventricular arrhythmias
What is the initial dosing schedule for amiodarone?
What is the maintenance dose?
Initial: 200mg TDS for 1 week, then 200mg BD for 1 week, then maintenance dose
Maintenance: 200mg OD
What potential adverse effects may be brought on by amiodarone therapy?
- Corneal microdeposits- rarely interfere with vision but drivers may be dazzled by headlights at night
- Phototoxicity- skin sensitive to sun light. Advise patients to use wide spectrum sunscreen
- Hyper/hypothyroidism- contains iodine (S&S- weight loss, palpitations and insomnia)
- Slight grey skin discolouration (very common)
What are the monitoring requirements for amiodarone?
- Thyroid function test- every 6 months
- LFTs- before treatment and every 6 months thereafter (any signs of hepatotoxicity- STOP TREATMENT)
What might a new/progressive SoB or cough indicate in amiodarone-taking patients?
Pneumonitis (inflammation of lungs)
With which other drugs does amiodarone INCREASE the risk of arrhythmias
- Amitriptyline
- Lithium
- Quinines
- Erythromycin
- Haloperidol
Is amiodarone safe in pregnancy and BF?
Pregnancy- possible risk of neonatal goitre (doffuse of nodular enlargement of the thyroid gland). Only use if no alternative
BF- Avoid; present in milk in significant amounts; theoretical risk of neonatal hypothyroidism from release of iodine
What is the mode of action of beta blockers?
Reduce cardiac output by BLOCKING beta-receptors in the heart
Also act on beta-receptors in the liver, bronchi and pancreas
When are beta blockers contraindicated?
Uncontrolled heart failure
What kind of beta blocker should asthma and COPD patients recieve?
Examples?
Cardio-selective BBs
Atenolol, bisoprolol, Metoprolol, nebivolol and acebutolol
What are the side effects of beta blockers?
- GI upset
- Headache, dizziness, fatigue
- coldness of extremities
- Sleep disturbances (nightmares)
- Affect carbohydrate metabolism- causing hypoglyacemia
When should beta blockers be avoided where possible?
- Asthma and COPD- action on bronchi can cause bronchospas
- Diabetes- action on pancreas and liver can reduce cardbohydrate metabolism and induce hypo/hyperglycaemia (use with caution)
Where should beta blockers be used in caution?
Diabetic patients- can mask hypoglyceamia
Cardioselective BB may be preferred
Wht are beta blockers indicated for?
- Angina- reducing workload of heart and prevent recurrence of MI
- Anxiety symptoms
- Migraine prophylaxis
Examples of cardioselective beta blockers
- Acebutol
- Atenolol
- Betaxolol
- Bisoprolol
- Celiprolol
- Metoprolol
- Nebivolol
Examples of non-selective beta blockers
- Carvedilol
- Labetalol
- Nadolol
- Oxprenolol
- Pinolol
- Propranolol
- Stotalol
- Timolol
What is the mode of action of digoxin?
Increase the force of myocardial (heart muscle) contraction and reduced contractivity of the AV node
What is digoxin indicated for?
- Atrial fibrillation
- Heart failure
What is the dosing schedule for digoxin?
What is their dose determined by ?
Long half life so OD dosing
However, if patient not feeling effects then can be BD
Dose determined by renal function
If required, when should bloods be taken for digoxin monitoring?
At least 6 hours after a dose
What are the S&S of digoxin toxicity?
- N&V
- Blurred/yellow vision
- Weight loss
- Anorexia
- Palpitations
- Hallucinations
- Abdominal pain
How is digoxin toxicity treated?
Does the formulation affect the dose?
A digoxin specific antibody e.g. Digifab
YES- liquid and tablets have different bioavilabilities
What is tranexamic acid indicated for?
Dosing schedule?
- Prevent bleeding associated with excessive fibronylosis e.g. surgery, dental extraction
- Management of menorrhagia
- 2-3 500mg tablets BD/TDS
What is the mode of action of tranexamic acid?
Inhibits excessive fibrinolysis (prevents blood clots from being broken down)
What is venous thromboembolism (VTE)?
Which two conditions come under this?
Thrombus (clot) formation in a vein
Deep-vein thrombosis (DVT) + Pulmonary Embolism (PE)
Which patient groups are at greater risk of venous thromoelmbolism?
- > 60 years old
- Limited mobility (secondary care- long stay!)
- Obesity
- Malignant disease
- Thrombophilic disorder
- History of VTE
What is pulmonary embolism?
Blocking of a vein from the heart to the lungs
How is VTE managed?
Prophylaxis with Low Molecular Weight Heparin (LMWH) e.g. apixaban
How is VTE managed in patients with renal failure?
Unfractionated heparin
What is given to patients if suffering with a haemorrhage while taking unfractionated heparin?
Protamine- given to reverse effects of unfractionated heparin
Only partially effective for LMWH
Can heparin be given in pregnancy?
What else may be preferred?
Yes- it doesn’t cross the placenta
However, LMWH preferred due to reduced risk of osteoporosis and heparin-induced thrombocytopenia (low platelet count)
What are the side effects of heparin?
- Thrombocytopenia (reduced platelet count)
- Hypokalaemia (low potassium)
What is the dosing schedule for a LMWH?
Duration of action is longer so is OD
What is warfarin indicated for?
- Atrial fibrillation
- Deep vein thrombosis (DVT)
- Pulmonary embolism (PE)
What is the mode of action of warfarin?
How long before effects are felt?
Vitamin K antagonist (needed to produce clotting factors)
Usually takes at least 48-72 hours to feel full effect
If effect is needed sooner, use a heparin
How are doses calculated for warfarin?
What are the target ranges for AF, DVT, PE and mechanical aortic valves
Dose calculated based on patients INR
Targets:
* AF, DVT and PE = 2.5
* Mechanical aortic valve = 3.5
What are the counselling points for warfarin?
Ensure dose taken at same time each day
How often should INR be monitored?
Initially and then once stable?
Initially- daily or alternate days
Stable- longer durations up to 12 weeks apart
What patient changes may affect INR and require more frequent monitoring?
- Decreased liver function
- Medication changes
- Diet
- Smoking
- Alcohol intake
- Recent weight loss
- Acute illness
- Diarrhoea and vomiting
What is the main adverse effect of warfarin?
and how is it managed?
Haemorrhage (bleeding)
Warfarin stopped immediately and patient started on vitamin K
What is the management if no bleeding present but INR > 8
What if INR is 5-8
Give vitamin K orally, and withhold warfarin
Just withhold warfarin (no vitmain K)
How is warfarin therapy managed around elective surgery
and patients at particularly high risk of VTE
Stopped 5 days prior to surgery
Restarted almost immediately after the procedure
If high risk VTE, given ‘bridging’ therapy with LMWH- should be stopped 24h before surgery and restarted 48 hours after
How are warfarin patients managed during emergency surgery?
Given vitamin K with prothrombin complex depending on timescale
Which regimen has a greater bleeding risk?
Aspirin + Warfarin
or
Clopidogrel + Warfarin
Clopidogrel + Warfarin
Can warfarin be given in renal impairment?
Yes- increased frequency of INR monitoring needed in severe impairment
What is aspirin typically indicated for?
Secondary prevention of cardiovascualr disease (75mg OD)
can be given with prasugrel/ticagralor for prevention of thrombotic events in acute coronary syndrome (sudden reduced blood flow to heart)
What is the dosing regimen for rapid digitalisation in digoxin therapy?
0.75-1.5mg over 24h in divided doses
Common Se of digoxin
- Dizziness
- Blurred vision
- Skin rash
What can cause increased levels of serum digoxin?
- Renai imapirment (renally cleared)
- Low body weight
- P-glycoprotein transport inhibitors e.g. amiodarone, verapamil, macorlides (-mycin), azole antifungals (fluconazole), ciclosporin
Vigorous diuresis may result in…?
Increased risk of acute hypotension (low BP)
How is gravitational oedema managed?
Movement alone
How is cerebral oedema managed?
Osmotic diuretic i.e. IV mannitol
What can be used to manage altitude sickness prophylaxis
Carbonic anhydrous inhibitors e.g. acetazolamide
What complication can commonly arise from thiazide-like and loop diuretics?
Hypokalaemia- low potassium
Dangerous in severe CVD, esp in patients on cardiac glycosides e.g. digoxin
What can hypokalaemia in heart failure precipitate?
Encephalopathy- reduced blood flow/oxygen to the brain
How does hypokalaemia affect magnesium levels?
Increases risk of hypomagnesia (low magnesium)
This can lead to increased risk of arrhythmia in alcoholic cirrhosis
What is the mode of action of thiazide-like diuretics?
Inhibits the NaCl channel in proximal segment of the distal convoluted tubule
What are thiazide-like diuretics indicated for?
Treat oedema due to chronic heart failure
What condition can thiazide-like diuretics exacerbate
Diabetes
Do NOT use in gestational diabetes
What are the common side effects of thiazide-like diuretics?
- GI disturbances
- Postural hypotension
- Hypokalaemia (avoid in refractory hypokalaemia)
What should be monitored while using thiazide-like diuretics?
U&Es
When should thiazide-like diuretics be taken?
Ideally in the morning
Can cause urinary urgency during the night
What are the bendroflumethiazide doses for oedema and HTN?
- Oedema- 5-10mg daily
- Hypertension- 2.5mg daily
What are the indapamide doses for regualr and SR forms?
Regular- 2.5mg OM
SR- 1.5mg OM
What is the mode of action for loop diuretics?
Inhibits reabsorption of NaCl in the loop of Henle
Results in increased excretion of water and loss of calcium and magnsium ions
What are loop diuretics indicated for?
- Chronic heart failure
- Pulmonary oedema due to left ventricular failure
- often used with anti-hypertensives to increased BP control
What are the common side effects of loop diuretics?
- GI upset
- Pacreatitis
- Hepatic encephalopathy
- Postural hypotension
Common loop diuretics and thier dosing regimens
- Bumetanide- 1mg OM
- Furosemide- 20-40mg daily. MAX 120mg daily (resistant oedema dose)
Both act within 1 hr
Are potassium sparing diuretics given for hypertension?
Why?
No- when given with ACEi or ARBs, increased risk of hyperkalaemia
What must not be given with potassium sparing diuretics
Potassium supplementation
How should MR potassium supplements be taken?
Whole, with a full glass of water
Whilst sitting/standing
What is amiloride indicated for?
What else is typically given in this regimen?
- Oedema
- Hepatic cirrhosis with ascites
Given with furosemide (combination drug i.e. Frumil 40mg/5mg tabs)
What is the mode of action of aldosterone and subsequently aldosterone antagonists?
Example?
- Aldosterone sysnthesised by adrenal glands and binds to mineralcorticoid receptors in kidney, colon and sweat glands
- Increases reabsorption of sodium and water and excretion of potassium
- Antagonists reduce this action and decreases sodium reabsoprtion and potassium excretion
e.g. spironalactone