cardio Flashcards
What is the first line drug therapy for SVT?
Adenosine
What is the MOA for adenosine?
Activation of GPCR on cell surfaces -> reduces spontaneous depolarisation, increases resistance to depolarisation. Increases refractoriness of AV node.
Adverse effects of adenosine
Bradycardia
Asystole
Sinking feeling in chest
Breathlessness
Absolute contraindications to adenosine
Hypotension
Coronary ischaemia
Decompensated HF
Asthma
Relative contraindications to adenosine
COPD
Heart transplant - particularly sensitive to effects
Adenosine interactions
Dipyramidole - blocks cellular uptake of adenosine
Theophylline, aminophylline, caffeine - competitive antagonists of adenosine receptors, block effect
Administration of adenosine
Initial dose 6mg, then 12 if needed
LARGE BORE cannula - green or above
Administered as rapid IV injection then flushed immediately
Other info - adenosine
Continuous cardiac rhythm strip needed - constant monitoring
What drug is administered as a vital part of anaphylaxis and ALS management?
Adrenaline
What is the MOA of adrenaline?
Agonist of α1, α2, β1 and β2 adrenoceptors - vasoconstriction of vessels supplying abdominal organs, vasodilation of vessels supplying heart
Adverse effects of adrenaline
Adrenaline induced hypertension Anxiety Tremor Palpitations Angina MI Arrhythmias
Absolute contraindications to adrenaline
None in cardiac resus protocols
Injection into areas supplied by an end artery eg extremities
Relative contraindications to adrenaline
Heart disease - used with caution
Interactions with adrenaline
β-blockers - may induce widespread vasoconstriction
Administration of adrenaline
1mg IV given after 3rd shock then every 3-5 mins
ANAPHYLAXIS - 500mg IM from minijet
What drug is first line for ascites and oedema due to liver cirrhosis?
Spironolactone
What drug is first line (with a β-blocker and ACE inhibitor) for chronic HF?
Aldosterone antagonists - spironolactone, epleronone
What is the MOA of aldosterone antagonists?
Inhibit the effect of aldosterone by competitively binding to the aldosterone receptor. This increases sodium and water excretion and potassium retention.
Adverse effects of aldosterone antagonists
Hyperkalaemia!!!!
Gynaecomastia
Liver impairment - Stevens-Johnson syndrome
Absolute contraindications of aldosterone antagonists
Severe renal impairment
Hyperkalaemia
Addison’s
Relative contraindications of aldosterone antagonists
Pregnant lactating women - can cross placenta and appear in breast milk
Potassium supplementation - should only be done in specialist practice
Interactions of aldosterone antagonists
Any potassium sparing drug eg ACE inhibitor, ARB - increases risk of hyperkalaemia
Administration of aldosterone antagonists
Only available as oral tablet
100mg daily orally for ascites
25mg daily orally for HF
Any other info on aldosterone antagonists
Spironolactone is weak diuretic, takes several days to act, so initially prescribed with loop or thiazide diuretic until it takes effect - this counteracts K wasting and potentiates diuretic effect
Normally 5:1 eg spiro 200mg furosemide 40mg
What drug is first line for BHP?
Alpha blockers
What drug is used in combination with ACE inhibitors, CCBs, and thiazide diuretics for resistant hypertension?
Alpha blockers eg doxazosin, tamsulosin, alfuzosin
What is the MOA of alpha blockers?
Block α1-adrenoceptor found in smooth muscle - causes vasodilatation and a fall in blood pressure, and reduced resistance to bladder outflow
Adverse effects of alpha blockers
Postural hypertension
Dizziness
Syncope
all more prominent after first dose
Absolute contraindications of alpha blockers
Existing postural hypertensions
Interactions of alpha blockers
Due to BP lowering effects, may be worth omitting one dose of current regime as BP tends to drop severely - particularly applicable to β-blockers
Administration of alpha blockers
Only available as oral tablet
Doxazosin 1mg orally daily then increased by 1mg weekly as needed (BPH and HTN)
Tamsulosin 400mcg orally daily (BPH only)
Any other info on alpha blockers
Due to hypertension risk, may be best to take this at bedtime
What drug is given as rhythm control for tachyarrhythmias eg AF, flutter, SVT, VT, VF?
Amiodarone
What is the MOA of amiodarone?
Blockade of sodium, calcium and potassium channels, and antagonism of α- and β-adrenergic receptors -> reduction in spontaneous depolarisation, can break reentry circuit and restore sinus rhythm
Adverse effects of amiodarone
Hypotension - during IV infusion Pneumonitis Bradycardia AV block Hepatitis Photosensitivity Grey discolouration Thyroid abnormalities
Absolute contraindications to amiodarone
Severe hypotensions
Heart block
Active thyroid disease
Interactions of amiodarone
Diltiazem, digoxin, verapamil - increases plasma concentrations of these, doses should be HALVED when started on amio
Administration of amiodarone
VF/pulseless VT - 300mg IV after 3rd shock
Any other info on amiodarone
IV infusion should always be accompanied by continuous cardiac monitoring
What is the drug that is first line for HTN?
ACEi
What is the drug that is first line for heart failure?
ACEi
What is the drug that is first line for ICD?
ACEi
What is the drug that is first line for diabetic nephropathy?
ACEi
What is the MOA of ACEi?
Block the action of the ACE, to prevent the conversion of angiotensin I to angiotensin II -> reducing of aldosterone promotes sodium and water excretion
Adverse effects of ACEi?
Hypotension Persistent dry cough Hyperkalaemia Renal failure Angioedema Anaphylactoid reactions