pharmacology of hypertension Flashcards
what are some examples of angiotensin converting enzyme inhibitors
ramipril
lisinopril
perindopril
what is the primary mechanism of action of ACEi
inhibit ace
prevent conversion of angiotensin 1 to 2
what are the main side effects of ACEi
cough hypotension hyperkalaemia foetal injury - AVOID IN PREGNANT WOMEN can cause renal failure in patients with renal artery stenosis can cause urticaria/angioedema
extra info on acei
most (not linsinopril) - are pro drugs. require hepatic activation to generate active metabolites required for therapeutic effects.
eGFR and serum k+ must be regularly monitored.
what are some examples of ccbs
amlodipine
felodipine
what is the mechanism of action of ccb
block l type calcium channels predominantly on vascular smooth muscle. results in decrease in calcium influx - with downstream inhibition of myosin in light chain kinase and prevention of cross-bridge formation. resultant vasodilation reduces peripheral resistance
primary target of calcium channel blockers
l type calcium channel
what are some side effects of ccbs
ankle oedema
constipation
palpitations
flushing/headaches
extra info on ccbs
dihydropyridine type calcium channel blockers demonstrate higher degree of vascular selectivity
what are some examples of thiazide/ thiazide like diuretics
bendroflumethiazide (thiazide)
indapamide (thiazide like)
what is the mechanism of action of thiazide/thiazide like diuretics
block na+ cl- co transporter in distal collecting tube
therefore na+ and cl- reabsorption in inhibited. osmolarity of tubular fluid increases, decreasing osmotic gradient for water reabsorption in collecting duct
what is the target of thiazide or thiazide like diuretics
sodium chloride cotransporter
what are the side effects on thiazides/thiazide like diuretics
hypokalaemia
hyponatremia
metabolic alkalosis - increased hydrogen ion excretion
hypercalcaemia
hyperglycaemia - from hyperpolarised pancreatic beta cells
hyperuricemia
extra info on thiazide and thiazide diuretics
both lose their diuretic effects within 1-2 weeks of treatment. continuing anti - hypertensive action appears to be due to vasodilating properties
what are the examples of angiotensin receptor blocker
losartan
irbesartan
candesartan
what is mechanism of action of arbs
act us non competitive antagonists at at1 receptors - found on kidneys and vasculature
what is the target of arbs
angiotensin 1
what are the side effects of arbs
hypotension
hyperkalaemia -
foetal injury - AVOID IN PREGNANT WOMEN
renal failure in patients with renal artery stenosis
extra info on arbs
most trials indicate that they are not as effective as acei
losartan and candesartan - - require hepatic activation to generate active metabolites required for therapeutic effects
what is clearance
measure of ability of body to eliminate a drug, may occur liver, kidney and other organs
what is elimination half life
length of time required for concentration of particular drug to decrease to half its starting dose in body
what is the time to peak plasma levels
time to peak concentration is time required for drug to reach peak conc in plasma. the faster the absorption rate, lower time to peak plasma concentration
why does the diuretic effect of thiazides only last for 1-2 weeks
kidney becomes tolerant to diuretics because there is a rebound activation of renin angiotensin system which counteracts diuretic effect due to increasing na reabsorption
* continuing hypertensive effect is due to further vasodilating action
