M103 T3 L11 Flashcards
What three drugs can be administered for the 1LoT for hypertension depending on age and race?
ARBs, ACE inhibitors & CCBs -- angiotensin receptor blocker ACE inhibitor calcium channel blocker
What are the different LoTs for hypertension?
2nd line = a combination of all 1st line drugs
3rd line = 2nd line + a diabetic
4th line = 3rd line + another diuretic (an a/b-blocker)
What are the different LoTs for hypertension?
2nd line = a combination of all 1st line drugs
3rd line = 2nd line + a diabetic
4th line = 3rd line + another diuretic (an a/b-blocker)
What are the side effects of ACE inhibitors?
dry cough (main - around 20 - 25 % of patients)
hypotension
renal impairment
hyperkalaemia
What drug blocks the action of kininase II?
ACE inhibitors
What is the function of kininase II?
breaks down substance P and badikinin into inactive peptides
How do ACE inhibitors cause a dry cough?
their aim is to block ACE
They accidentally also block kininase II - an enzyme related to ACE
Not enough kininase II leads to a build up of substance P and badikinin in the body
These are both irritants
can cause respiratory tract sensitivity
leads to a dry cough
What is the most common reason for the intolerance of ACE inhibitors by patients?
bc it can stop patients and their partners from sleeping
in these cases, the ACE inhibitors should be removed
How do ACE inhibitors cause hypotension?
angiotensin II can have effects on a whole range of systems which are all designed to keep bp high
so when the amount of angiotensin in the system is suddenly reduced, bp plummets quite dramatically
What are some consequences of hypotension caused by ACE inhibitors if taken during the day?
if the patient changes position or stands up very suddenly, they can feel very faint bc their bp is quite low
can cause collapse and a potential head injury
How are some of the side effects of hypotension caused by ACE inhibitors reduced?
prescribe the initial dose of the ACE inhibitor to be taken at night time
if the patient takes it just before they go to bed when they’re lying down, they won’t fall down
so if bp is low, it’s not going to cause them any injury
usually, as the dose wears off by the morning, the patients’ bp is at a high enough level
so when they get out of bed, they’re not at risk of fainting
Are the side effects of hypotension caused by ACE inhibitors long term problems and why?
no
usually the body gets used to the dose of the ACE inhibitors over time
eventually it is no longer a problem
Why is it important to measure the patients’ renal functioning before giving them ACE inhibitors?
How and why this done?
ACE inhibitors can cause renal impairment
how - by measuring creatinine levels in the blood
why - elevation in blood creatinine levels indicate faulty renal functioning
How is low blood flow in the kidneys brought to normal levels?
renin is synthesised, creates angiotensin II, a vasoconstrictor
glomerular pressure increases, so blood flow does as well
How do ACE inhibitors cause renal impairment?
reduce levels of angiotensin II
reduce the ability of this efferent vessel to constrict
What are the effects of hyperkalaemia?
increased cardiac & NS excitability
arrhythmias
epileptic attacks
What are the normal K+ levels in the blood compared to that for hyeprkalaemia?
3 - 5 mM
above 5 mM
When are the patients’ serum K+ levels monitored?
before the ACE inhibitor is administered
before increasing in the dose of ACE inhibitor
Why are ACE inhibitors useful for patients with diabetes and hypertension?
they protect the kidneys from diabetic nephropathy
they don’t have any effects on blood lipids
so the fact that these drugs don’t affect serum glucose or serum lipids in a negative way means that they are very good drugs for the treatment of diabetes and hypertension
What is the suffix for all ACE inhibitor drugs?
-pril
What are the effects of Angiotensin receptor antagonists?
hyperkalemia
renal impairment
side effects are minimal
What are aldosterone antagonists used for?
can also be front line hypertension treatment for patients with primary aldosteronism
What are the three main classes of calcium channel blockers?
dihydropyridines
phenylalkylamines
benzothiazepines
How do dihydropyridines work?
blocks a portion of L-type Ca2+ channels on smooth muscle of arterioles
calcium entry into the smooth muscle cells will be reduced
AAR the smooth muscle will relax, arterioles will dilate
peripheral resistance will dcs, bp will dcs
How do phenylalkylamines and benzothiazepines work?
they preferentially target L-type channels in the heart
they d thcse frequency and force of contraction
What is an example of each of the main classes of clacium channel blockers?
dihydropyridine - amlopidine
phenylalkylamines - verapamil
benzothiazepines - diltiazem
When are phenylalkylamines and benzothiazepines used?
less used to treat hypertension
only in those patients whose hypertension is due to a tachycardia faster than normal heartbeat
Whaet is the mechanism by which calcium leads to muscle contraction?
in smooth muscle cells there are L-type calcium channels
calcium entry in a smooth muscle cell
leads to an increase in intracellular calcium
binds to calmodulin protein which activates the Myosin light chain kinase enzyme
MLCK phosphorylates MLC
allows myosin and actin to interact and muscle contraction