Cardiovascular / Blood Drugs Flashcards
How do Loop Diuretics work?
Inhibit Na+/K+/2Cl- Co-transporter in the loop of henle
So water doesn’t re enter bloodstream with these ions
It also directly improves contractile ability of “overstreched” heart muscle
When would a loop diuretic be prescribed?
Relieve breathlessness in acute pulmonary oedema (with oxygen and nitrates)
Fluid overload in chronic heart failure
Other oedematous states
What other heart failure medicine do you need to be careful with when it is prescribed with Furusemide?
Digoxin, increased risk of digoxin toxicity due to diuretic associated hypokalaemia.
When wouldn’t you use furosemide?
Severe hypovolaemia or dehydration
Caution in those at risk from hepatic encephalopathy
In hypokalaemia / hyponatraemia
What side effects would you look out for in someone taking furosemide?
dehydration
hypotension
hypomagnaesia, hypocalcaemia, hydrogen loss (alkalosis?)
Hearing loss and tinnitus
How is furosemide excreted?
In the urine
What would you tell a patient before they are started on furosemide?
They will go to the toilet more (so don’t take late at night)
Why they are taking it
Its side effects
Name a Thiazide diuretic and explain how they work
Inhibits Na+/Cl- co-transporter in the distal convoluted tubule. This prevents sodium (and associated water) reabsorbtion.
When would a thiazide diuretic be used?
Hypertension, first line in children or if in heart failure (i.e. when calcium channel blocker not appropriate). Also as an add on for poorly controlled hypertension
When would a thiazide diuretic be less effective?
when prescribed with an NSAID (low dose aspirin not a problem)
When are thiazide diuretics contraindicated?
Hypokalaemia
Hyponatraemia
Gout (increases uric acid concentration)
What does contraindicated mean?
A situation when the drug in question should not be prescribed
Name some side effects of Thiazide like diuretics
Potential impotence in men
Hyponatraemia (not usually a problem)
Hypokalaemia (can cause heart arrhythmias)
How are thiazide like diuretics eliminated?
Rapidly renally
Patient info for thiazide like diuretics?
Water tablet for high blood pressure
Will make you go to the toilet more
Impotence in men possible
Other side effects
What is spirinolactone, and how does it work?
Potassium sparing diuretic
Inhibits reabsorbtion of sodium (and therefore water) in distal convoluted tubule
Weak diuretic on its own
When would you prescribe spirinolactone?
When treating hypokalaemia brought on by loop or thiazide diuretic therapy
When wouldn’t you use spirinolactone?
When a patient has hyperkalaemia or is on potassium elevating drugs e.g. K+ supplements or aldersterone antagonists.
When someone is volume depleted
When someone has severe renal impairment
What are the possible side effects of spirinolactone (all are uncommon)
GI upset
Dizziness
Hypotension
Electrolyte disturbances
What would you tell a patient before starting them on spirinolactone?
To counteract the potassium loss caused by other water tablet.
Will still need the loo a lot!
Drink a lot of water.
How does Atenolol (Beta-blocker) work?
Reduce the force and speed of contraction of the heart
By binding to Beta-1 receptors on myocardium (Beta-2 mainly in smooth muscle)
What effects does the action of beta-blockers have on the cardiovascular system?
Relieves cardiac ischaemia by reducing O2 demand
Protect heart in from chronic sympathetic stimulation in HF
Prolongs refractory period, slowing heart rate
Lowers BP by reducing renin secretion by kidneys (medicated by Beta-1 receptors)
What drug is first line treatment of angina and acute coronary syndrome?
Atenolol
When would you use Atenolol?
Angina from ischaemic heart disease (first line)
Chronic heart failure (first line)
AF (first line) to reduce rate
Supraventricular tachycardia (SVT) to restore sinus rhythm
Hypertension when other medications insufficient.
With what kind of cardiac drug is atenolol contrainidicated due to its interactions?
Non-dihydropyridine calcium channel blockers
When are beta blockers contraindicated?
Asthma (bronchospasm) - beta-2 receptors in airway
COPD: use Beta-1 specific drugs eg Atenolol
Heart block
Haemodynamic instability
What are some side effects of beta blockers?
Fatigue, cold extremities, headache and GI disturbance common
Sleep disturbance, nightmares!
Rarely impotence in men
How is atenolol eliminated?
95% renally
What would you tell a patient before starting them on beta-blockers?
To help your heart and cardiovascular system
Side effects
May initially worsen symptoms, but will get better
What kind of drug is Ramipril?
ACE (Angiotensin converting enzyme) Inhibitor
How do angiotensin converting enzyme inhibitors work?
Block ACE. Stops angiotensin 1 converting to angiotensin 2. (Angiotensin 2 is a vasoconstrictor and promotes aldosterone secretion).
Reduces peripheral resistance, lowering BP
Works especially well in efferent glomerular arteriole, so lowered intraglomerular pressure, slowing CKD
What is the suffix of ACE inhibitors?
-pril, e.g. Ramipril
When would you use and ACE inhibitor?
Hypertension (first line)
Chronic heart failure (first line)
Ischaemic heart disease
Diabetic neuropathy
What drug interactions do ACE inhibitors have?
Avoid with potassium elevating eg spirinolactone due to hyperkalaemia risk Avoid NSAIDS (increases risk of renal failure)
When are ACE inhibitors / ARBs contraindicated?
Renal artery stenosis of AKI
Pregnancy, breastfeeding
Name some side effects of ACE inhibitors
Persistent dry cough Hypotension (particularly on first dose) Hyperkalaemia Can worsen renal failure Rare: angiodema and anaphylactic
How are ACE inhibitors / ARBs eliminated?
Renally
What would you tell someone starting on ACE inhibitor?
To lower BP
Dry cough, dizziness, rarely anaphylactic
Avoid OTC antiinflammatories (ibuprofen)
Yearly blood tests
Name an Angiotensin receptor blocker
Losartan
How does Losartan work?
Block angiotensin 2 at AT1 receptor, stopping its effects.
Why would losartan be used instead of an ACE inhibitor?
When ACE inhibitor not tolerated (usually due to dry cough)
What is losartan used for?
Hypertension
chronic heart failure
ischaemic heart disease
When are ARB’s contraindicated?
Renal artery stenosis
AKI
pregnantcy / breastfeeding
What would you tell someone before starting them on an angiotensin receptor blocker (ARB)?
Replacing ACE inhibitor with this (probably due to cough)
Dizziness possibility
Yearly blood tests
Avoid NSAIDS
Name some examples of nitrites
GTN (glyceryl trinitrate)
isosorbide nitrates
What is the mechanism of nitrates?
Converted to NO
NO increased cGMP in vascular smooth muscle cells, relaxing them (vasodilation)
Reduces cardiac preload and left ventricular filling.(reducing work and O2 demand)
Can releive coronary vasospasm and dilate coronary vessels, increasing perfusion
Indications of short acting nitrates eg GTN spray?
Acute angina (reperfuse heart)
Indications of long acting nitrites eg isosorbide mononitrate?
Angina where beta blocker / calcium channel blocker not effective
IV nitrates, along with oxygen and furosemide is used to treat what?
Pulmonary oedema