M3 L2: Antihypertensives Flashcards
what is bp
- force circulating blood exerts on the arterial walls
- heart pumps out blood into diff tissues thru arteries
- circulating blood carries; nutrients and O2 to tissues, waste and CO2 back to the heart
normal arterial bp
120/80
systolic: heart contraction (1st #)
diastolic: heart relaxation (2nd #)
factors controlling BP
- blood volume
- increased volume, increased BP
- decreased volume, increased BP - peripheral resistance
- vasoconstriction (VC) to increased pressure to increased bp
- vasodilation to decreased pressure to decreased bp - sympathetic nervous sys activity:
- increased SNS to increased noradrenaline to vasoconstriction to increased BP
- decreased SNS to decreased noradrenaline to vasodilation to decreased bp
Renin-angiostensin-aldosterone sys (RAAS)…
RAAS sys
- bp falls
- angiotensinogen
renin - angiotensin `
angiotensin-converting enzyme - angiotensin 2
- aldosterone -> salt retention
OR - ADH
which results in bp rising
what is hypertension
PB > 140/90
mild: 140-159/90-99
moderate: 160-179/100-109
severe: greater of more than 180/greater or more than 110
Must do the blood pressure 3x while patient is at rest to be sure and diagnose
When a patient is stressed - put them in a quiet room with dim light to let them relax
types of hypertension
primary hypertension:
- no identifiable cause
- most common
secondary hypertension:
- caused by underlying disease (renal disorders, endocrine disorders, pregnancy, etc)
- treat the problem: for example treat Cushing syndrome (that adds steroids, if you fix this blood pressure will reduce)
hypertension risk factors
non controllable: genetics, age, etc
controllable: physical activity, smoking, food, etc
diagnosis of hypertension
- usually asymptomatic
- based on measuring BP
- manifestation of complications
Hypertension may be the first manifestation you see, could lead to something much worse like heart failure
complications of hypertension
heart:
- left ventricular hypertrophy
- heart failure
- CAD (coronary artery disease)
- PAD (peripheral artery disease)
brain:
- TIA
- cerebral strokes
- encephalopathy
eyes:
- hypertensive retinopathy
- papilledema
- loss of vision
kidneys:
- renovascular disease
- renal failure
control of hypertension
- life long
- target values:
hypertension alone: less then 140/90
hypertension + DM (diabetes): less than 130/80 - decrease incidence of complications
- increase compliance!
hypertension non compliance
causes:
- dietary ex: high salt
- meds: cost, side effects, long term therapy
improvement: behavioural changes
treatments for hypertension (3)
non-pharmacological measures
pharmacotherapy
treatment of complications
hypertension non-pharmacological measures
modification of lifestyle
- dietary management
- change habits
pharmacotherapy: antihypertensive drugs
diuretics (specially thiazide diuretics), sympatholytics, calcium channel blockers (CCB), drugs acting on RAAS, vasodilators
sympatholytics
- decreased SNS activity
include: - α blockers
- β blockers
- α and β blockers (ex: labetalol - pregnancy)
- adrenergic neuron blockers (ex: reserpine, guanethidine, methyldopa - pregnancy)
- centrally acting drugs (clonidine)
α blockers
1. mechanism
2. other uses
3. side effects
4. example
- block α receptors -> decrease constricting effect of norepinephrine on smooth muscle cells of blood vessels -> vasodilation
- prostatic enlargement, raynaud’s disease
- orthostatic hypotension -> syncope
- prazosin
β blockers
1. mechanism
2. side effects
3. types
widely used
cardioprotective
1. block β receptors and decrease SNS effect on cardiovascular sys (all decrease: HR, myocardial contractility, cardiac output, myocardial o2 demand, renin secretion)
2.
- bronchospasm, -> asthma
- bradycardia -> heart block
- heart failure
- impotence
3.
- nonselective β antagonist ex: propranolol
- selective β1 antagonist (cardioselective) ex: atenolol (THIS ONE IS GOOD)
Side effects: BAD FISH
B: bradycardia/bronchospasm
A: av blocks/arrythmias
D: depression/dizziness
F: fatigue
I: impotence
S: signs of hypoglycemia
H: hypotension
Avoid In elderly because of the adverse effects
drugs acting on RAAS
- angiotensin converting enzyme inhibitors (ACEI)
- angiotensin receptor blockers (ARB)
ACE Inhibitors
1. mechanism
2. pros
3. cons
4. example
- angiotensin-converting enzyme
- safe in asthma, no impotence, useful in diabetes
- dry cough, hyperkalemia, teratogenic
- captopril, enalapril, ramipril
angiotensin receptor blockers
1. mechanism
2. examples
- block the action of angiotensin 2 at the AT-1 receptors
- sim effect as ACEI
- lower incidence of cough - losartan, valsartan
vasodilators
dilate blood vessels
classification:
- arterial dilators ex: hydralazine
- venous dilators ex: organic nitrates
- combined ex: sodium nitroprusside
choice of antihypertensive
- encourage monotherapy
- effective w minimal side effects
- more suitable for patient’s condition
recommended:
- old age, heart failure - diuretics
- DM - ACEI or ARB
- CAD - selective β1 blockers
- Pregnancy - methyldopa or labetalol
- prostatic enlargement - α blockers
avoid:
- β blockers in asthma and advanced HF
- ACEI/ARB during pregnancy
initial monotherapy of hypertension
thiazide diuretics
β blockers
ACEI/ARB
Calcium channel blockers (CCB)
can use acronym “ABCD”
A - angiotensin converting enzyme inhibitors, angiotensin receptor blockers
B - β blockers
C - calcium channel blockers
D - diuretics - thiazides
