Drugs Influencing the CVS Flashcards
Which class of drugs are called the “prils”?
Angiotensin Converting Enzyme Inhibitors
Why do you get a dry cough when on ACE inhibitors?
ACE metabolises bradykinin normally. Therefore bradykinin builds up on ACE inhibits and irritates the vagus nerve
What the therapeutic effects of ACE inhibitors?
Reduce vascular tone
Reduce aldosterone production
Reduce cardiac hypertrophy
What class of drugs are called the “sartans”?
Angiotensin Receptor Antagonists
What therapeutic effect do angiotensin receptor antagonists have?
Reduce peripheral vasoconstriction
Reduce aldosterone
Reduce cardiac hypertrophy
Reduce sympathetic activity
How do loop and thiazide diuretics cause hypokalaemia?
They block Na resorption in the loope and collecting duct so that its concentration is high in the collecting duct > This causes a relative increase in Na reabsorption there leading to K loss (due Na/K ATPase exchange)
How do you treat the hyperkalaemia caused by the angiotensin system inhibitors?
Couple the treatment with a thiazide diuretic to increase K loss in the collecting duct
Which class of drugs is called the “olols”
The beta-adrenoceptor antagonists
What are the therapeutic effects of the beta-adrenoceptor antagonists?
Reduce CO via reducing HR and contractility
Reduce renin release
What are the therapeutic effects of calcium channel blockers?
Reduce cardiac/vascular contractility
Or
Reduce vascular resistance - dilation
Depends on their selectivity
Why do ACE inhibitors sometimes cause acute renal failure?
Because angiotensin II exerts tonic vasoconstriction of efferent arterioles
What is the mechanism by which nitrates cause vasodilation?
The drug is transformed and releases NO > stimulates guanylate cyclase in vascular smooth muscle, converting GTP to cGMP > dephosphorylates the myosin light chain and leads to vascular relaxation > vasodilation
What are aquaretics?
Substances that promotes water loss without accompanying electrolyte loss
How do K sparring diuretics work? What is an example of one?
Aldosterone receptor antagonist
- stops aldosterone activating ENaC and synthesis of Na/K ATPase in the collecting duct
= Blocks Na reabsorption in exchange for K
Spironolactone
