cardiac Flashcards
differences between JNC 7 and JNC 8
- JNC 8 (2014): for targeted BP management: recommend use of 4 different meds (removed beta blockers)
- JNC 7 (2004): 5 different meds (added beta blockers)
Post JNC 8 Evidence
- SPRINT Trial
- NIH funded multicenter RCT
- Lower systolic BP (<=120) greatly decreases CV complications and death in older adults
- decreased risk of death by 25% and decreased rate of cardiac morbidity by 1/3
- there are few advances in medicine that truly warrant an immediate change in practice, but the SPRINT trial appears to be one such study
stage 1 HTN
- systolic 130-139 or diastolic 80-90
stage 2 HTN
systolic >/ 140 or diastolic >/90
lifestyle recommendations to reduce BP
- DASH eating
- exercise
- reduce sodium dietary intake
- moderate alcohol
- weight loss
hypertensive crisis
systolic: higher than 180
diastolic: higher than 120
calcium channel blockers: MOA
blocking the inward movements of calcium through the cell membranes of cardiac and smooth muscle cells
This results in:
* decreased cardiac muscle contraction
* decreased cardiac conduction between AV & SA nodes
* vasodilation of coronary arteries and peripheral arterioles
which leads to
* decreased CO, HR, and coronary artery spasms
CCBs uses
- arrthymias (verapamil, diltiazem)
- angina (verapamil, diltiazem, nifedipine, amlodipine, felodipine)
- hypertension (all)
CCBs common side effects
- nifedipine and diltiazem: pedal edema (r/t peripheral artery vasodilation), headache
- nifedipine: flushing, dizziness
- verapamil: constipation
CCBs prescribing considerations
- what am I treating? which sub-class of CCB is most appropriate?
- how old is my patient?
CCBs contraindications
- hx of heart failure or MI
-giving med that decreases contraction of heart will worsen HF and AMI - hepatic impairment (since all drugs are metabolized by liver)
pt education CCBs
- do not stop the medication abruptly
-rebound effects (HTN, tachycardia
-may cause increased severity and duration of chest pain - monitor for & report signs of hypotension and CHF
- Do not take with grapefruit juice (CYP-450 inhibitor)
ACE-I (-prils): MOA
- block angiotensin converting enzyme from converting angiotensin I to angiotensin II- a potent vasoconstrictor
- inhibit the breakdown of bradykin0 a potent vasodilator
ARBs (-sartan): MOA
- block the binding of angiotensin II to its receptors
- do not affect bradykin levels
uses of ACE-I and ARBs
- HTN
- CHF
- acute/post MI
- left ventricular dysfunction
- diabetic nephropathy–ACE I first line to tx diabetes
side effects of ACE-I and ARBs
- cough (ACE-I only) most common
-can persist 2-6 weeks (even if switched to ARB) - dizziness
- hyperkalemia
- elevated renal function tests
- angioedema
prescribing considerations: ACE-I and ARBs
- what am I treating?
- age of pt–> older patients caution with polypharmacy ex K-sparing meds- check med list
- pregnant or of childbearing age–birth defects
- hx of renal insufficiency–check baseline RFTs and Na/K
education ACE-I and ARBs
- well tolerated
- if cough develops with ACE-I then switch to ARB–may persist 2-6 weeks even after switch
- monitor renal function and electrolytes periodically (3-6 months after starting), esp with dose change
- some pts have a precipitous drop in BP with the first dose of ACE-I, esp pts on also diuretics
-take while sitting down
beta blockers: MOA
block beta receptors resulting in:
- ↓ the workload of the heart through decreases in heart rate (chronotropy)
-↓ strength of myocardial contraction (ionotropy
- Blocks epinepherine/norepinephrine leading to vasodilation
beta blockers indications
- CAD – all patients should be on BB post MI unless contraindicated
- Angina
- Heart Failure
- Arrhythmias
- HTN
-The effect of the beta-blockers on BP is minimal but rapid (~1 week - Other: migraine prophylaxis, essential tremor, hyperthyroid, pregnancy induced hypertension (labetalol)
contraindications beta blockers
- 2nd/3rd degree heart block – do EKG before starting
- Decompensated heart failure
- Symptomatic bradycardia
- Do not combine with non-DHP CCBs (2 meds decreasing HR)
side effects beta blockers
Bradycardia, worsened HF, fatigue/drowsiness, depression, dizziness, decreased HDL, bronchoconstriction, erectile dysfunction
use caution: beta blockers
- Use caution in patients with DM
-Can increase insulin resistance and decrease insulin release from the pancreas = hyperglycemia
-Can mask s/s of hypoglycemia
avoid: beta blockers
- Avoid abrupt discontinuation
-Increases risk of MI
-Titrate down slowly
Cardioselectivity of Beta Blockers:
- Cardioselective beta blockers preferred – especially in asthma/lung disease
-Atenolol
-Esmolol
-Metoprolol
-Bisoprolol
-Nebivolol - Even cardioselective BBs can result in some bronchospasm
alpha blockers: MOA
Blocks the alpha 1 adrenergic receptor on vascular (arteriole and venule) smooth muscle and ↓ vascular resistance
alpha blockers common drugs
- Doxazosin (CARDURA)
- Prazosin (MINIPRESS)
- Terazosin (HYTRIN)
side effects of alpha blockers
- No sexual side effects
- Increased risk of hypotension/ hypotension related side effects
adverse reactions alpha reactions
- First-dose phenomenon - hypotension
- Reflex tachycardia
- Orthostatic hypotension
- Dizziness, palpitations, headache
- Priapism (prolonged erection in men)
- Stress incontinence in women
-Generally avoided in women
ALLHAT Collaborative Research Group (2000). JAMA, 283: 1967.
- Increased incidence of heart failure in pts treated with doxazosin
- Use is therefore limited to compelling indications such as BPH, sexual dysfunction
alpha blockers use
Generally, 3rd or 4th line except in patients with BPH
Sympatholytics: MOA
Inhibit the actions of the central nervous system
* Beta blockers
* Alpha Blockers
* Centrally acting agents (clonidine, methyldopa)
Diuretics in Heart Failure
- Furosemide is the most prescribed loop diuretic in heart failure
-BUT: study stating torsemide is better—more improvement in functional status and lower cardiac mortality/hospitalizations in patients w/ HF
loop diuretics: MOA
inhibit Na/K/Cl cotransporter in the Loop of Henle which inhibits reabsorption of sodium and chloride leading to increased water excretion
Loop diuretics: indications
o Edema/fluid overload 2/2 CHF, cirrhosis, renal disease – most common use
o Hypertension (in those with renal insufficiency)
*Less effective at BP lowering and more effective at diuresis than thiazides
common loop diuretics
Furosemide, torsemide, bumetanide (PO or IV)
high oral bioavailability
Torsemide and bumetanide - oral and IV
adverse effects of loop diuretics
Diuresis related
* Risk of hypokalemia, hypocalcemia, hypomagnesemia, hyponatremia
* Hyperuricemia
* Metabolic acidosis
Hypersensitivity reactions
* Furosemide, torsemide, bumetanide are sulfonamides – risk for rash or acute interstitial nephritis (rare)
* Minimal allergic cross reactivity with sulfonamide abx
* Ethacrynic acid – non sulfonamide loop diuretic
Ototoxicity
* Transient or permanent deafness
* Highest risk with high dose IV therapy or lower doses in patients with kidney impairment or concurrent use of other ototoxic drugs such as aminoglycosides
* Ethacrynic acid – higher risk of ototoxicity
* Rate of administration is important – continuous infusion less risky than bolus
potassium sparing diuretics (spironolactone): MOA
- Blocks Na+ movement in & also prevents K+ movement out of cells
-Acts on collecting tubule—mild diuretic effect
Potassium-sparing diuretics (Spironolactone): common uses
- Edema: especially related to chronic liver failure (combo with loop diuretic)
- CHF, when hypokalemia is a problem (earlier stage)
- Drug resistant HTN
-Not first line but may be added to a thiazide - Hyperaldosteronism (Spironolactone & eplerenone)
- Anti-androgen properties
- PCOS
- Hirsutism
- Acne
- Female pattern hair loss
Common Drugs: potassium sparing diuretics
Amiloride, triamterene, spironolactone
contraindications potassium sparing diuretics
- Caution with other meds that may increase K
- Caution in renal impairment
- Caution in women of childbearing age
-Ensure adequate contraception - Caution in men
-Risk for gynecomastia, impotence, loss of libido - Lab monitoring controversial in young healthy persons
diuretics
- Most powerful of these classes= one acting on ascending loop of Henle (loop diuretics)
- Second powerful: thiazide
- Least powerful class: acting on collecting tubule & duct (spironolactone, amiloride, triamterene)
thiazide direutics: MOA
Inhibit Na and Cl transport reduces blood volume and CO reduces peripheral resistance
thiazide diuretics: most common
hydrochlorothiazide (most common), chlorthalidone, indapamide
Contraindications: thiazide diuretics
- Renal/hepatic disease
- Gout
- Hypokalemia
- Sulfa drug allergy (contains sulfa molecule)
indications of thiazide diuretics
Hypertension
* Decrease risk of CVA and MI in hypertension
* Often considered first-line therapy in hypertension (effective, safe and cheap)
* Increasing dose does not increase efficacy and increases risk for side effects
Edema
* Related to CHF, cirrhosis, CKD, corticosteroids, nephrotic syndrome
adverse effect thiazide diuretics
- Dose-Dependent
-Higher dose–> more side effects - Hypokalemia (monitor K+)
- Dehydration
-Particularly in the elderly
-Leads to orthostatic hypotension (dangle feet prior to getting off bed) - Hyperglycemia
-possibly because of impaired insulin release 2º hypokalemia - Hyperuricemia
-thiazides compete with urate for tubular secretion - Hyperlipidemia
-Mechanism unknown but cholesterol increases usually trivial (1% increase) - Impotence
- Hyponatremia
-Due to thirst, sodium loss, inappropriate ADH secretion (can cause confusion in the elderly), usually after prolonged use
Thiazide like vs. Thiazide type diuretics
Thiazide like = same physiologic properties but different chemical structure
Thiazide like (chlorthalidone/indapamide)
- Longer half-life = more pharmacologic effect
-12% additional risk reduction for CV events
-21% additional risk reduction for HF - Reduce platelet aggregation and vascular permeability
- Possible increased risk of hypokalemia
- Dosage: 25-50mg (similar to HCTZ)—don’t need to know
Thiazide type (HCTZ)
- More commonly prescribed in the US
- Dosage: Recommend 12.5-25 mg , no significant benefit over 25mg
-Start at lower doses
dihydropyridines–nifedipine
decrease output: minimally
decrease HR: minimally
increase vasodilatio: significantly
phenylakylamines–verapamil
decreased CO: significantly
decreased HR: significantly
increased vasodilation: moderately
benzothiazepines–diltiazem
decreased CO: moderately
decreased HR: significantly
increased vasodilation: moderately
