Pharmacology of Hypertension Flashcards
what is the MOA for angiotensin converting enzyme inhibitors? (ACEi)
ramipril lisinopril
inhibits angiotensin converting enzyme
prevents conversion of angiotensin I to angiotensin II by ACE
what is the drug target for ACEi? (ramipril lisinopril)
angiotensin converting enzyme
what are the main side effects for ACE inhibitors? (ramipril. lisinopril)
cough
hypotension
hyperkalaemia
foetal injury
renal failure
urticaria/angioedema
what do most ACE inhibitors (excl lisinopril) require?
require hepatic activation as they are pro-drugs
what must be monitored in patients prescribed ACE inhibitors? (lisinopril ramipril etc)
eGFR and serum K+
what is the MOA for calcium channel blockers? (amlodipine)
block L type Ca2+ channels (mostly on vascular smooth muscle)
decrease calcium influx
so - downstream inhibition of myosin light chain kinase, prevention of crossbridge formation
therefore vasodilation - reduced peripheral resistance
what is the drug target for calcium channel blockers? (amlodipine)
L type calcium channels
what are the main side effects of calcium channel blockers? (amlodipine)
ankle oedema
constipation
palpitations
flushing/headaches
give examples of calcium channel blocker drugs
amlodipine
felodipine
what is the MOA of thiazide/thiazide like diuretics? (indapamide or bendroflumethiazide)
blocks Na+, Cl- co transporter in early distal convoluted tubule
reabsorption of Na+ inhibited
osmolarity of tubular fluid increases, decreased osmotic gradient for water reabsorption in collecting duct
what is the drug target for thiazide like diuretics? (indapamide or bendroflumethiazide)
sodium/chloride transporter in early distal convoluted tubule
what are the main side effects of thiazide like diuretics? (indapamide or bendroflumethiazide)
hypokalaemia & hyponatraemia
metabolic alkalosis
hypercalcaemia
hyperglycaemia
hyperuricaemia
how long does the diuretic effect of thiazide like diuretics last with treatment?
1-2 weeks
vasodilating properties continue
give an example of a thiazide like diuretic
indapamide
what is the MOA of angiotensin receptor blockers? (ARBs) (losartan)
non competitive antagonists at AT1 receptor on kidneys and vasculature
what is the drug target for ARBs? (candesartan, losartan)
angiotensin 1 receptor on kidneys and vasculature
what are the main side effects of ARBs? (losartan, candesartan)
hypotension
hyperkalaemia
foetal injury
renal failure
what is more effective - ARBs or ACEi? (ramipril lisinopril VS losartan, candesartan)
ACE inhibitors
what is stage 1 hypertension?
135/85 to 149/94mmHg
when is treatment to be started in stage 1 hypertension?
if target organ damage CVD renal disease diabetes 10yr CVD risk >10%
what is stage 2 hypertension?
150/95mmHg or over
immediate start drug treatment
why are ACEi associated with cough?
prevents bradykinin breakdown
bradykinin builds up, causes muscle spasms
results in dry cough
what is the MOA for ARBs?
competitive inhibitor for AT-1 therefore prevents angiotensin II binding
therefore reduce downstream aldosterone synthesis, vasodilate, downregulates sympathetic activity (by reduced effects of angiotensin II)
what population should ACEi be avoided in
pregnant women
those with renal artery stenosis
what population should ARBs be avoided in?
pregnant women - risk of foetal injury
when to take ambulatory or home blood pressure monitoring
if clinic BP reading is over 140/09mmHg
first line treatment for hypertension in diabetes
ACEi or ARB
(acei better)
then CCB or thiazidelike diuretic if needed
first line treatment for 55+ hypertension/ afro carribean
calcium channel blocker
then ACEi if required
first line treatment for hypertension in under 55s/ non-afro carribean
ACEi or ARB
then CCB or thiazidelike diuretic if needed
