Hypertension Flashcards
Hypertension risk factors
- Age (>50 years)
- SBP
- Pulse pressure
- Alcohol/smoking
- Diabetes
What is the goal of treating hypertension?
reduce associated morbidity and mortality from CV events
ACC/AHA BP guidelines: Hypertensive crisis
Systolic >180
and/or
Diastolic >120
Mean arterial pressure (MAP)
MAP = (SBP x 1/3) + (DBP x 2/3)
What is the major determinant of SBP?
Cardiac output
What is the major determinant of DBP?
Total peripheral resistance (TPR)
What are the 6 groups of antihypertensives?
- RAAS
- ACE inhibitors
- Angiotension II Receptor Blocker - Sympathetic Antagonists/Agonists
- Beta blockers
- Alpha 1 blockers
- Central alpha 2 agonists - Calcium channel blockers
- Diuretics (thiazide)
- Aldosterone antagonists
- Direct vasodilators
Agents that block production or action of angiotensin: basic action
reduce peripheral vascular resistance
Sympatholytic (sympathoplegic) agents: basic action
- reduce peripheral vascular resistance by inhibiting cardiac function
- increase venous pooling in capacitance vessels
Calcium channel blockers: basic action
inhibit calcium influx leading to coronary and peripheral vasodilation
Diuretics: basic action
deplete body of sodium and reduce blood volume
Aldosterone antagonists: basic action
inibit aldosterone resulting in inhibition of sodium and water retention and inhibiting vasoconstriction
Direct vasodilators: basic action
relax vascular smooth muscle thus dilating resistance vessels and increasing capacitance
Where are the 4 sites diuretic agents act in the nephron?
- Proximal convoluted tubule (PCT)
- Thick ascending limb of loop of Henle
- Distal convoluted tubule
- Cortical collecting tubule
What part of the kidney is responsible for 60-70% of the total reabsorption of sodium?
Proximal convoluted tubule
also major site of bicarbonate reabsorption
Carbonic anhydrase inhibitors: subclass
Acetazolamide
Carbonic anhydrase inhibitors: clinical applications
- Glaucoma
- Mountain sickness
- Edema with alkalosis
Carbonic anhydrase inhibitors: Toxicities, interactions, contraindications
- metabolic acidosis
- Sedation
- Paresthesias
Name 3 loop diuretics
- Bumetanide
- Furosemide *
- Torsemide
Name 4 thiazide diuretics
- Chlorthalidone
- Hydrochlorothiazide (HCTZ) *
- Indapamide
- Metolazone
Name 2 Potassium sparing diuretics
- Amiloride (with or without HCTZ)
- Triamterene * (with or without HCTZ)
Name 2 Aldosterone Antagonists
- Spironolctone * (with or without HCTZ)
- Eplerenone
Diuretics: overall mechanism
- blocks reabsorption of sodium and chloride
- diuresis results in decreased plasma and stroke volume
What is the major site of calcium and magnesium reabsorption?
Thick ascending limb of the Loop of Henle
Loop diuretics: target
Na/K/Cli tri transporter
20-30% of sodium is reabsorbed here
Thick ascending limb of the loop of Henle
Why is furosemide given IV in ED
oral bioavailability goes down the more the fluid in the body
Loop diuretics: mechanism
*fluid eliminator
- more potent diuresis
- smaller decrease in PVR
- less vasodilation (HCTZ more effective at lowering BP)
Loop diuretic: mechanism
blocks Na+, K+, Cl- symporter at the thick ascending loop of Henle
Loop diuretic: efficacy
- Diuresis > BP lowering
- Preferred in heart failure of severe edema
- Less likely to cause hyperglycemia, hyperlipidemia
-useful when GFR <30 or serum creatinine of 2.5-3
Loop Diuretic: drug interactions
*similar to HCTZ
- increase effect of digoxin and certain antiarrhythmics
- increases levels of lithium
- NSAIDS may decrease efficacy
Loop diuretics: side effects
- hypokalemia
- hypomagnesemia
- hypocalcemia *
-hypovolemia
- hyperuricemia
- ototoxicity
Which diuretic has decreased absorption with edema of the bowel?
Loop diuretics (Furosemide, bumetanide, torsemide)
If a patient had too much hypercalcemia what two meds could you give?
furosemide and torsemide
What do thiazide diuretics target?
cotransporter (Na+ and Cl-) in the distal convoluted tubule
Calcium is reabsorbed in the distal convoluted tuble under control of ____________
parathyroid hormone
Thiazide Diuretics: name 4
- HCTZ*
- Chlorthalidone*
- Metolazone
- Indapamide
Thiazide diuretics: mechanism
blocks reabsorption of sodium and chloride in the distal convoluted tubule via NaCl Carrier: NCC
How do thiazide diuretics affect blood pressure?
- decrease in peripheral vascular resistance
- direct smooth muscle relaxation
What are the clinical applications of thiazide diuretics?
- hypertension
- mild heart failure
What are the electrolyte imbalances thiazide diuretics can precipitate?
- hypokalemia
- hyponatremia
- hypercalcemia
- hyperglycemia
- hyperlipidemia
- hyperuricemia
Is chlorthalidone a thiazide diuretic?
No, but effects are indistinguishable.
**Longer duration of action
Thiazides: limitations
- GFR <30 for HCTZ
- Unrestricted salt intake reduces efficacy
What needs to be monitored with thiazides?
- BUN
- Creatinine
- Uric acid level **
- electrolytes (K+, Na+, Ca++, Mg+++)
HCTZ and Chlorthalidone: dosage
low dose is as effective
Metolazone (thiazide) dosage note
more effective with concurrent kidney disease
Indapamide (thiazide) dosage
does not alter serum lipid levels
Thiazide drug interactions: what do they increase effect/levels of?
- ACE inhibitors
- Carbamazepine
- Lithuim
- Oxcarbazepine
- Topiramate
- ARB
Thiazide drug interactions: What do they decrease levels/effectiveness of?
antidiabetic agents
NSAIDS
Name the things that increase levels/effects of HCTZ
- Alcohol
- Opioid
- Barbiturates
- Beta-2 agonists**
- corticosteroids**
- licorice**
Sodium reabsorption in the colecting tubule is controlled by?
aldosterone
Where is ENaC located, primary site of acidification of the urine and last site of potassium excretion?
Collecting tubule
Where do potassium-sparing diuretics work?
collecting tubule
Potassium sparing diuretics: Spironolactone warnings:
- Hyperkalemia
- Hyponatremia
- Gynecomastia
Potassium sparing diuretics: amiloride cautions?
Hyperkalemia
Aldosterone antagonists (spironolactone) efficacy
- modest diuresis
- Monitor K+ levels
Alternative uses of aldosterone antagonists
- female acne and hirsutism
- HTN in peds
- Diuretic in peds
Amiloride, triamterene are what type of medication?
Potassium sparing diuretics
Amiloride, triamterene: contraindications
- renal failure
- avoid in patients with ACE inhibitors
Amiloride, triamterene: mechanism
blocks epithelial Na+ channel action proximal to the distal convoluted tuble = stops K+ secretion
When should triamterene be avoided?
low creatinine clearance (<10ml/min)
Potassium sparing diuretics: amiloride, triamterene- Drug interactions
-decrease cardiac glycoside, quinidine (antiarrhythmics)
Important actions of ACE inhibitors
- Reduces direct stimulation by angiotensin II on myocardial cells to help prevent or regress LVH
- Reduces angiotensin II mediated vasoconstriction and aldosterone secretion
- Bradykinin accumulated= vasodilation by releasing nitric oxide
ACE and ARB adverse effects
- Hyperkalemia
- taste disturbances
- increase in serum creatinine (modest ~35%)
ACE inhibitor adverse effects
- cough
- angioedema
What type of patient are ACE and ARB most effective in?
- *young white patient
- Diabetes mellitus patients
(less effective in blacks and older patients)
What should you monitor in a patient on ACE or ARB?
- serum creatinine*
- K+ (so it doesn’t get too high)
- BUN
- CBC with differential in collagen vascular disease and/or renal impairment
What effect does PDE55 medication have on ACE and ARB?
PDE5 (ex. Cialis) may increase levels of ACE and ARB
When is ARB and ACE contraindicated?
pregnancy
Aliskiren
renin inhibitor
What type of patient should ACE, ARB, and renin inhibitors be avoided?
- Hyperkalemia
- Pulmonary (cough)
- Chronic Kidney disease
- Pregnancy
Where are alpha 1 receptors located?
peripherally
arterioles and venules
Where are alpha 2 receptors located?
- centrally located
- regulates alpha 1
Beta 1 receptors
- sympathetic
- adrenergic
- increase HR
- increase contractility
- Renin release (heart and kidney)
Beta 2 receptors
- sympathetic
- adrenergic
- vasodilation of arterioles and venules
- bronchodilation
- gluconeogenesis
Parasympathetic nervous system has what type of receptors
muscarinic
Name the 5 locations of muscarinic receptors
- CNS
- Heart
- Smooth muscle
- Peripheral nerves
- Glands
Which beta blocker is non-selective (B1 and B2)
Propranolol
Which beta blocker is selective for B1
Metoprolol
Mechanism of action: Beta blockers
-negative chronotropic
-negative inotropic
decreased CO
-inhibit release of renin
Beta blockers: side effects
- bradycardia
- AV conduction abnormalities
- development of acute heart failure
- Bronchospasm (Asthma,COPD)
- Transient increase in blood glucose and serum cholesterol
- Increase in TG and decrease in HDL
*AVOID abrupt cessation ( taper over 1-2 weeks)
Which beta blockers are cardioselective?
- atenolol
- metoprolol
Which beta blockers ISA?
- acebutolol
- pindolol
(increase risk post MI- rarely used)
Which beta blockers have a membrane stabilizing effect?
all of them
Name 2 important things to monitor with beta blockers?
- CHF (edema, new cough, dyspnea, weight gain, unresolved fatigue)
- Blood sugar in diabetes
Do you need to adjust beta blocker dose in renal impairment?
no, but may need to lower dose in hepatic impairment
Propranolol and metoprolol undergo extensive _____________
first pass effect
Name 2 drugs that are both beta 1 blockers and alpha 1 blockers and do no raise TG or lower HDL?
Labetolol and Carvedilol
Prazosin, terazosin, doxazosin drug class
Alpha 1 blockers
Alpha 1 blockers: mechanism
inhibit uptake of catecholamines in smooth muscle resulting in vasodilation
-Cross the blood brain barrier
Alpha 1 blockers: side effects
-First dose phenomenon: dizziness, faintness, palpitations, syncope
- Vivid dreams
- Priaprism
- Sodium and water retention with higher doses (give with diuretic)
In a male patient with BPH, what medication could be useful?
Alpha 1 blocker
Alpha 1 blockers (prazosin, terazosin, doxazosin) drug interactions
- decrease levels of dabigatran, linagliptin (anticoagulants)
- vincristine (diabetes medication)
Clonidine, methldopa drug class?
Central alpha 2 Agonists
Central alpha 2 agonists: mechanism
-stimulate alpha 2 receptors in the brain which reduces sympathetic outflow from the vasomotor center and increases vagal tone
Methyldopa side effects
sodium and water retention so give with diuretic (unless pregnant, then don’t give diuretic)
-hepatitis (transient rise in LFTs), stop if LFT persistently elevated or alk phos increases
Clonidine side effects
anticholinergic effects: sedation, dry mouth, constipation, urinary retention, blurred vision
SLUDGE
-Rebound hypertension with stopping abruptly
What is first line HTN treatment in pregnant patients?
methyldopa
Central Alpha 2 Agonist drug interactions
- MAO inhibitors
- Increase effect of antihypertensives, beta blockers, lithium, PDE5, SNRI, tricyclic antidepressants
Why add thiazide diuretic to central alpha 2 agonists?
central alpha 2 agonists can cause sodium and water retention
Reserpine
peripheral adrenergic antagonist
How does reserpine work?
depletes norepinephrine from sympathetic nerve ending
Which medications should be given with a diuretic?
- Central alpha 2 agonists (clonodine, methyldopa)
- Peripheral adrenergic antagonist (reserpine)
Side effects of reserpine (peripheral adrenergic antagonist)
- sodium and water retention
- Reflex parasympathetic activity: nasal stuffiness, increased gastric acid secretion, diarrhea, and bradycardia
Name the two classes of vasodilators
- Calcium channel blockers
2. Direct arteriole vasodilators
Verapamil and diltiazem
Non-dihydropiridines
Amlodipine, fetodipine, nicardipine, isradipine, nifedipine
dihydropiridines
When would you consider using nondihydropyridine CCB (verapamil and diltiazem)?
- consider using as addition to diuretic
- elderly patient
- Consider as first line in African americans
Dihydropyridine CCB do they alter conduction through the AV node?
no (nondihydropyridines do though)
When to use caution in CCB?
renal and hepatic impairment
Calcium channel blockers: side effects
- gingival hyperplasia, peripheral edema
- Verapamil: constipation
- caution with Beta blocker as can increase chance of heart block
- Nifedipine metabolism inhibited by large quantities of grapefruit juice (>1 quart)
Direct Arterial Vasodilators
hydralazine, minoxidil
Why do you need to use a beta blocker or clonidine with hydralazine (direct arterial vasodilator)?
direct arterial vasodilators activate baroreceptors with compensatory increase in sympathetic outflow (increased HR, CO, renin)
Which drug can give dose dependent lupus-like syndrome (slow acetylators are prone?
Hydralazine
Which medication can give hypertrichosis?
minoxidil
Alternative use of minoxidil??
male pattern baldness
Osmotic diuretic
mannitol
How is mannitol (osmotic diuretic given?
IV (short duration)
What is the major action of mannitol and where does it work?
Mannitol is filtered but not reabsorbed so exhibits osmotic effect.
-Used to reduce brain volume and intracranial pressure but extracting water from the tissue into the blood
Cautions with Mannitol (osmotic diuretic)
- hyponatremia followed by hypernatremia
- headache
- nausea
- vomiting