Antihypertensives Flashcards
what are the ACE (angiotensin converting enzyme) inhibitors
captopril, enalapril, lisinopril
clinical uses of ACE inhibitors
hypertension (first line for primary)
heart failure
myocardial infarction
albuminuria in non pregnant patients
why aren’t ACE inhibitors first line agents for blacks and elderly
because the RAAS system is less active in them
how does ACE inhibitors work?
- it blocks conversion of angiotensin I to angiotensin II hence reducing its vasoconstrictive activity and release of aldosterone
- blocks degradation of bradykinin and stimulates release of vasodilators such as prostacyclin and prostaglandin E2
- increase in renin since no neg feedback from angiotensin II
- slight increase in serum creatinine
- rise in K+ levels in blood if renal insufficiency
how do you dose the ACE inhibitors
enalapril and lisinopril given once a day while captopril given two to three times daily
adverse effects of ACE inhibitors
CATCHH
Cough (due to bradykinin)
Angioedema
Teratogen (fetal renal malformation; renal failure in those with bilateral renal artery stenosis)
Creatinine (increased due to decreased GFR)
Hypotension
Hyperkalemia (due to reduction in aldosterone)
ACE inhibitors are contraindicated in who
bilateral renal artery stenosis (no vasoconstriction by angiotensin II on the efferent arteriole to help maintain glomerular capillary pressure and filtration)
hyperkalemia (due to reduction in aldosterone release hence less sodium absorption so less K excretion)
pregnancy (teratogen – fetal renal malformation)
what are the angiotensin II receptor blockers (ARBs)
Losartan
Valsartan
clinical use of ARBs (angiotensin II receptor blockers)
hypertension and heart failure
when do you switch from an ACE inhibitor to an ARB if they both work almost the same way
when the patient is experiencing the bradykinin mediated dry ass cough
when do ARBs work equally effective in black/oldies as it does in whites/youngings
when combined with calcium channel blockers
mechanism of ARBs
- they block the receptor that mediates the effects of angiotensin II hence no vasoconstriction or release of aldosterone
- don’t block the breakdown of bradykinin so no dry ass cough or angioedema (as seen in ACE Inhibitors)
- since angiotensin II not activating its receptor, no negative feedback on renin release so renin still high
what are the adverse effects of ARBs?
hypotension
hyperkalemia (due to less aldosterone secretion hence less Na absorption so less K excretion)
angioedema
diarrhea
acute renal failure (no vasoconstriction on efferent arterioles from angiotensin II if bilateral renal artery stenosis so reduced glomerular capillary pressure and filtration)
contraindication of ARBs
pregnancy (fetal renal malformation)
bilateral renal artery stenosis
hyperkalemia
what are the calcium channel blockers (CCB)
VAND Verapamil (diphenalkylamine) Amlodipine (dihydropyridine) Nifedipine (dihydropyridine) Diltiazem (benzothiazepine)