Antihypertensive drugs 3- ACEi, ARB's Flashcards
list the common indications for ACEi (4)
1) Hypertension- 1st or 2nd line to reduce risk of stroke, MI and death by CVD
2) Chronic heart failure- 1st line in all grades, to improve symptoms and prognosis
3) Ischaemic heart disease- reduce risk of subsequent events such as MI and stroke
4) Diabetic neuropathy and CKD with proteinuria
outline the MoA of ACEi
1) Block the action of ACE to prevent the conversion of angiotensin I to angiotensin II
2) Angiotensin II is a vasoconstrictor, blocking its action reduces peripheral vascular resistance lowering BP. It also dialates the efferent glomular arteriole, which reduces intraglomerular pressure slowing down progression of CKD
3) Angiotensin II also stimulates aldosterone secretion. reduced aldosterone levels promote Na+ and water excretion, which is beneficial in heart failure
list the common side effects of ACEi
1) Hypotension (esp after first dose)
2) persistent dry cough ( due to inc in bradykinin which is usually inactivated by ACE)
3) Hyperkalaemia (lower aldosterone promotes potassum retention)
4) rare but important side is angoedema and anaphylactoid reactions
how can ACEi cause or worsen renal failure particularly in patients with renal artery stenosis
They can cause AKI. people with renal artery stenosis rely on constriction of efferent glomerular arteriole to maintain filtration.
outline the use of ACEi and ARB’s in pregnancy
Avoid in pregnancy unless essential. They adversely affect fetal and neonatal blood BP control and renal function. skull defects and Oligohydramnios also reported
Discuss the risks associated with taking ACEi with other potassium elevating drugs and NSAIDS
1) Avoid taking with other potassium elevating drugs including K+ supplements and potassium sparing diuretics unless advised by specialist due to hyperkalaemia
2) NSAID + ACEi increases the risk of nephropathy
ACEi can cause profound first dose hypotension when taken for the first time especially if the patient is on a loop or thiazide diuretic, low sodium diet, dehydrated, or has heart failure. Explain how this can be reduced
1) For hypertension the first dose should be taken at bedtime
2) Start at low dose and titrate up gradually
3) Sometimes advisable to omit the diuretic dose that precedes the first dose of the ACEi
1) outline the monitoring requirements for ACEi and ARB’s
2) with reference to creatinine concentration, eGFR and potassium levels, when would ACEi/ARB’s be discontinued?
1) Check renal function and electrolytes before initiating treatment or increasing dose, monitor during treatment esp in elderly.
2) stop if sCr rises more than 30%
↳if eGFR falls more than 25%
↳if K+ rises >5mmol/L, stop other K-elevating drugs and nephrotoxic drugs. If still remains >5mmol/L reduce dose of ACEi/ARB. If it exceeds 6.0mmol/L stop ACEi/ARB and seek expert advice.
why should ACEi be used in caution in diabetics?
May lower blood glucose
why should ACEi be avoided or witheld during certain types of dialysis and before desensitisation with bee venom
to prevent anaphylactoid reactions
list the common indications for ARBs (4)
1) indications same as for ACEi: hypertension, chronic heart failure, Ischemic heart disease, diabetic nephropathy and CKD with proteinuria
2) ARB’s generally used when ACEi are not tolerated due to cough
Outline the MoA of ARBs, and explain how this differs from ACEi
ARBs block the action of angiotensin II on the angiotensin type 1 receptor. Whereas ACEi inhibit Angiotensin-converting enzyme therby preventing the conversion of angiotensin I to II. Both drugs have similar effects in the body
1) explain why ARBs are less likely to cause dry cough when compared to ACEi
2) why are ARBs preferred to ACEi in black people of African or Caribbean origin?
1) ARBs do not inhibit ACE, and therefore do not affect bradykinin metabolism.
2) they are less likely to cause angioedema for the same reason as above. incidence of angioedema related to ACEi is 5x higher in this group
outline the important adverse effects of ARBs
1) can cause hypotension (esp after first dose, can take first dose at night)
2) can also cause hyperkalaemia and renal failure esp in those with renal artery stenosis
what types of patients should ARB’s be avoided in?
1) Those with renal artery stenosis or AKI.
↳ but ARBs are valuable in some forms of CKD but lower doses are used and renal function monitored closely
2) in women who are or could become pregnant and those who are BF
→ Exactly the same as ACEi
