antihypertensives Flashcards
two types of hypertension
1) primary hypertension
- unknown cause
- essential, idiopathic
- 90% of cases
2) secondary hypertension
- known cause
- 10% of cases
benefits of treating hypertension
- lower risk of heart failure (50%)
- lower risk of stroke (38%)
- lower risk of heart attack (15%)
- lower risk of death (10%)
hypertension target organ damage
no obvious symptoms
- cerebrovascular disease (stroke)
- hypertensive retinopathy
- left ventricular dysfunction
- left ventricular hypertrophy
- coronary artery disease
- chronic kidney disease
- peripheral artery disease
hypertension treatment
combination of medication and lifestyle change
- obesity
- physical exercise
- salt intake
- increase potassium intake
- dietary habits including fat intake
- alcohol
- smoking
BP treatment targets
general population: <140/90
high risk (CV disease, CKD): <120/NA
diabetics: <130/80
first line hypertensive drugs
- angiotensin converting enzyme (ACE) inhibitors
- angiotensin II receptor blockers ( ARBs)
- calcium channel blockers (CCBs)
- diuretics
- b adrenoceptor blockers
single pill combinations recommended
other hypertensive drugs
- vasodilators
- adrenergic agents
ACE inhibitors
stop angiotensin I from becoming angiotensin II
- large group of safe and effective drugs
- often used at first line agents for HF and hypertension
- often combined with a thiazide diuretic or calcium channel blocker
RAAS system (renin angiotensin aldosterone system)
renin released into bloodstream by kidneys, acts on angiotensinogen from liver to become angiotensin I, in/around the lungs ACE enzyme converts angiotensin I –> angiotensin 2 which stimulates aldosterone secretion from adrenal glands. aldosterone increased HR and constricts arteries to increase BP
ACE inhibitor examples
-pril
captopril (short half life)
enalapril (PO or parenteral)
lisinopril and quinapril (longer half life)
ACE inhibitor indications
hypertension
- alone or with other agents (CCB, diuretics)
- renal protective effects in clients with diabetes
HF
- drug of choice in hypertensive clients with heart failure
- slows progression. of left ventricular remodelling after a MI
ACE inhibitor mechanism of action
- prevents ang II vasoconstriction (reduces peripheral resistance - afterload)
- prevents aldosterone release (reduce salt and water reabsorption)
- prevent breakdown of bradykinin (enzyme in lungs broken down by ang 1 but ACE inhibitors keep bradykinin and triggers cough)
ACE inhibitors adverse effects
- dry, nonproductive cough
- first-dose hypotension may occur
- possible hyperkalemia (stopping reabsorption of sodium)
ACE inhibitor interactions
k supplements and k sparing diuretics
ACE inhibitors contraindications
pregnancy
ARBs angiotensin 2 receptor blockers
similar to ACE
- no dry cough
- block receptor of angiotensin 2
ARBs examples
- losartan
- valsartan
ARBs mechanism of action
ang 2 receptor antagonist
- block receptors that ang 2 activates
- stops vasoconstriction
- blocks release of aldosterone