Pharmacology: cardiac rate, force and BP Flashcards
sympathetic NS innervation in the heart
NA and adrenaline activate B1-adrenoceptors (Gs)
parasympathetic NS innervation in the heart
ACh activates M2 muscarinic receptors (Gi)
examples of beta agonists
dobutamine
adrenaline
NA
effect of beta agonists
increase rate and force of cardiac output
what is adrenaline (alpha/beta agonist) used in?
cardiac arrest
anaphylactic shock
what is dobutamine used in?
heart failure (less tachycardia than other agonists)
examples of beta antagonists
propranolol
atenolol
bisoprolol
effect of beta antagonists
during exercise rate and force is significantly reduced
when are beta antagonists used?
excessive sympathetic during emotion AF and SVT angina heart failure (start low, go slow) hypertension (?)
adverse of beta antagonists
bronchospasm bradycardia hypoglycaemia fatigue cold extremities
example of a non-selective muscarinic ACh receptor antagonists
atropine
mechanism of action of non-selective muscarinic ACh receptor antagonists
increase HR (more pronounced in athletes)
when are non-selective muscarinic ACh receptor antagonists used?
bradycardia
anti cholinesterase poisioning
example of a cardiac glycoside
digoxin
mechanism of action of digoxin
blocks Na+/K+ ATPase (causes membrane to depolarise slightly)
when is digoxin used?
heart failure
adverse of digoxin
yellow vision
calcium sensitizers
levosimendan
increases Ca2+
decompensated heart failure
inodilators
amrinone and milrinone
increases contractiltiy
acute heart failure
two classes of drugs used in relax vascular smooth muscle
organic nitrates
CCBs
two example of organic nitrates
GTN
ISMN
mechanism of action of organic nitrates
dilation of collaterals increasing coronary blood flow (improved perfusion of the ischeamic zone)
when are organic nitrates used?
angina
pulmonary oedema
adverse of organic nitrates
headaches reflex tachycardia (beta blocker) formation of methaemoglobin hypotension tolerance
examples of CCBs
verapamil
amlodipine
diltiazem
mechanism of action of CCBs
reduce rate, force and SVR
when are CCB’s used?
hypertension
angina
SVT, AF
adverse of CCB’s
flushing
ankle oedema
hypotension
what drug to avoid in heart failure?
verapamil
two classes of drug that block the RAAS
- ACEI
2. ARB
mechanism of action of aliskiren
renin inhibitor, decreasing BP
example of an ACEI
lisinopril
mechanism of action of ACEI
blocks angiotensin I to angiotensin II blocking aldosterone production and inactivates bradykinin
when are ACEI used?
hypertension
heart failure
MI
adverse of ACEI
dry cough
hypotension
hyperkalaemia
angioedema
example of an ARB
losartan
mechanism of action of ARBs
block angiotensin II on AT1 receptors, but doesn’t inhibit bradykinin
when is ARBs used?
hypertension
heart failure
MI
what are both ACEI and ARB contradicted in?
bilateral renal artery stenosis
pregnancy
potassium channel opens
minoxidil and nicorandil
hyperpolarisation
used as last resort in hypertension and angina
adverse: reflex tachycardia and salt and water retention
alpha1-adrenoceptors
prazosin and doxazosin
vasodilation
prostatic hyperplasia and hypertension
adverse: postural hypertension
