Drugs Affecting ANS Flashcards
Adrenergic Agonist
Branches of the ANS
Know clonidine (Catapres)
MOA:* MOA: activation of central alpha2 receptors results in inhibition of cardioacceleration &
vasoconstriction centers in the brain
* Leads to decreased outflow of norepinephrine
* Leading to decreases in peripheral resistance, renal vascular resistance, HR & BP by reducing sympathetic function
* Can lead to compensatory effect of retaining sodium (expand blood volume)
* Thus, sometimes given with diuretic
Contraindications for clonidine
severe coronary insuf, recent MI, renal function impairment
* Avoid clonidine if risk of depression
Alpha 2 Agonists - Methyldopa (Aldomet) recommendations
pregnant women
breastfeeding women
Children <12
methyldopa special requirements
LFT
hemolytic anemia
doxazosin (Cardura)
terazosin (Hytrin)
Selective Alpha 1 Antagonist
MOA: blocks alpha 1 receptors in smooth muscle; vasodilates arteries
B. bladder neck and prostate smooth muscle (relieve outflow obstruction)
Selective Alpha 1 Antagonist Adverse Effects
Orthostatic hypotension - known for first dose effect - give dose at bedtime
-rebound tachycardia
-nasal congestion
-fluid retention
-sexual dysfunction
This class of drug may reduce total cholesterol & tryglycerides and increase HDL; enhance insulin sensitivity; regress LVH
Selective Alpha 1 Antagonists
doxazosin and terazosin
Beta Adrenergic Antagonists
Block sympathetic (adrenergic) response by competing for beta receptors
* ***practically all therapeutic effects result from beta 1 blockade in the
heart. The major consequences/actions of blocking these receptors are:
* 1. decrease HR
* 2. decrease contractility
* 3. decrease velocity of A-V conduction
* Also prevent renin release (less water retention)
Beta 1 Cardioselective drugs
metroprolol (Lopressor)
atenolol (Tenormin)
- Children
Non cardioselective B 1 & 2 drugs
propranolol (Inderal)
- Children
labetolol (Trandate)
- Alpha & Beta blockade
Third Generation Beta Blockers
nebivolol (Bystolic)
* Block beta1 - very cardioselective
* Increases nitric oxide release
* Approved for hypertension
* Less likely to produce
problematic DM effects
carvedilol (Coreg)
* BB noncardioselective
* Vasodilation by alpha blockade
* Approved for CHF, HTN, LV
dysfunction after MI
Beta blocker adverse effects
Beta 1 blockade:
* Bradycardia
* Decreased CO
* Precipitation of CHF (in high doses)
* A-V block
* Rebound cardiac excitation
- Beta 2 blockade:
- Bronchospasm
- Inhibition of glycogenolysis (breakdown of glycogen to glucose)
- Also impaired insulin release
- Fatigue, depression
- Sexual dysfunction/Impotence
BB Teaching points
- Teach patients to monitor:
- pulse daily (call if <50 bpm)
- blood glucose (diaphoresis is not masked)
- BP
- Do NOT abruptly withdraw (decrease by ½ q 4 days)
Angiotensin Converting Enzyme Inhibitors (ACE I)
- Block the enzyme that normally converts
angiotensin I to the potent
vasoconstrictor angiotensin II - By blocking the production of angiotensin
II, the drugs decrease vasoconstriction
and decrease aldosterone production
(thereby reducing retention of sodium
and water) - Reduce both preload and afterload
List ACE I
lisinopril (zestril)
captopril (Capoten)
ACE I uses
HTN
Hypertensive Protienuric Diabetes
- renal protective (slows progression of diabetic nephropathy
Angina and ischemic heart disease
post MI
Heart failture
ACE I Adverse Effects
- Cough
- Angioedema (swelling of face, eyes, lips, tongue)
- Occurs within first dose - 1st month
- Usually within 1st week
- Hyperkalemia
- Caution: renal impairment, salt substitutes, K-supplements, K-sparing diuretics
- Hypotension (dizziness, HA)
- Rash
- Neutropenia
- Renal insufficiency (monitor proteinuria, BUN, Creatinine)
ACE I Absolute Contraindications
Bilateral Renal Artery Stenosis
Angioedema
Pregnancy
NSAIDs reduce hypotensive effect
Angiotensin II Receptor Blockers (ARBs)
Instead of decreasing production of angiotensin II, these drugs compete for receptor sites.
No cough or angioedema
Still contraindicated in pregnancy
Losartan (Cozar)
valsartan (Diovan)
ARBs
Renin Inhibitor
aliskerin (Tekturna)
Direct renin inhibitor: decreases the conversion of
angiotensinogen to angiotensin I
* Plasma renin activity is not increased
* Use: HTN
* Adverse Effects:
* Angioedema, cough
* Hyperkalemia
* Substrate CYP 3A4
* Contraindication: pregnancy
Calcium Channel Blockers MOA
Block the influx of calcium which results in: * 1. relaxes arterial smooth muscle (decrease afterload)
* 2. decreases cardiac contractility (negative inotrope)
* 3. decreases sinoatrial (SA) and atrioventricular (AV) nodal conduction
* ***blocking action of CCBs occurs via different receptors
Non-Dihyropyridines MOA and Use
Calcium Channel Blocker
Primary site is heart * Decrease contractility
* Decrease conduction
* Dilate coronary arterioles
* Best choice for CAD * ***avoid in HF
* verapamil (Calan)
* diltiazem (Cardizem)
Dihydropyridines
Calcium Channel Blocker
Primary site is arterial smooth muscle * Thus, greater degree of vasodilation
* Best choice for hypertension * ***avoid in unstable angina (tachycardia)
and with significant peripheral edema
* amlodipine (Norvasc)
* nicardipine (Cardene)
* nifedipine (Procardia)
Calcium Channel Blockers Adverse Effects and concerns
Adverse Effects:
* HA, dizziness, hypotension
* Bradycardia (verapamil & diltiazem) – call if HR <50 bpm
* Peripheral edema
* Constipation (more with verapamil)
* Contraindications:
* 2nd or 3rd degree AV block
* Severe HF
* Aortic stenosis
* Work well in Black population
* All CCBs are on CYP 3A4 substrate * Careful with grapefruit juice (3A4 inhibitor)
hydralazine (Apresoline)
direct arterial vasodilator (decrease afterload)
* Limited effect on HTN when used alone B/C vasodilating action that decreases BP also stimulates compensatory
mechanisms:
* Increased HR (SNS)
* Sodium & water retention (RAAS)
* May take with beta-blocker (prevent the tachycardia) and diuretic (prevent sodium & water retention)
hydrochlorothiazide
chlorthalidone
Thiazide DiureticsMOA: Decrease reabsorption of Na & Chloride in the distal tubule; exert effect on luminal surface of the tubule; requires adequate renal perfusion
* Ex: hydrochlorothiazide (HCTZ)
chlorthalidone
* Uses: * Ineffective when immediate diuresis is required
* Primary use is long-term management of hypertension and HF
* Relatively ineffective with decreased renal function
* Assess for allergies to sulfonamides (chemically related)
- Orthostatic hypotension
- Electrolyte imbalances:
- Hypokalemia
- Hypercalcemia
- Hyponatremia
- Hypomagnesium
- Glucose intolerance (may impair pancreatic release of insulin & diminish tissue utilization of
glucose) - Dry mouth
- Potentiate uric acid retention
- Transient increases in chol, LDL, triglycerides
Adverse effects of thiazide diuretics
Loop Diuretic - Name two
furosemide (Lasix)
torsemide (Dermadex)
Loop Diuretics MOA
- MOA: Block reabsorption of Na and Chloride in the ascending loop of Henle, where the greatest Na reabsorption occurs
- Ex: furosemide (Lasix)
torsemide (Demadex) - Use:
- Hypertension
- HF
- Diuretic of choice when more rapid or potent effects are needed (pulm edema)
- Their sodium losing effect is up to 10X greater than thiazide diuretics
- May use with renal insufficiency (Creatinine clearance <25 mL/min)
- Schedule last dose early enough to prevent nocturia (4:00 pm)
Loop Diuretic Adverse Effects
Electrolyte imbalances:
* Hypokalemia
* Hypercalcemia
* Hyponatremia
* Hypomagnesium
* Excessive diuresis
* Orthostatic hypotension
* Glucose intolerance
* High doses = transient hearing loss
* Hyperuricemia
Loop Diuretics Teaching
- Maintain potassium levels in cardiac patients at 4-4.5 mEq/L
- Potassium supplement:
- PO – give with meals to decrease GI distress
- Liquid – mix with juice to improve taste
- Teach patient:
- Consume diet with potassium rich foods
- Report muscle cramps, irregular heart beat, weakness
K sparing diuretics
- MOA: Promote Na excretion but retain potassium in the distal tubule
- Ex: spironolactone (Aldactone)
- Aldactone antagonizes aldosterone (aldosterone promotes retention of sodium & water & excretion of K)
- Uses:
- Not used as often as primary diuretic (typically used in combo with K-losing diuretic)
- Primary utility is to block aldosterone action in HF
- Hypertension
- Good choice in pregnancy
- Contraindication: impaired renal function (due to risk of hyperkalemia)
- Adverse Effects:
- Hyperkalemia (teach pt to avoid high K diet; avoid salt substitutes that contain K chloride)
- Hypotension
- Hyperuricemia
- Gynecomastia
JNC VIII HTN Guidelines
First Line Classes:
* 1. Thiazides
* 2. ACE Inhibitors
* 3. ARBs (Angiotensin Receptor Blockers)
* 4. CCB (Calcium Channel Blockers)
No beta blocker
Initiating HTN Treatment
- > 60 yo <150/90
- <60 yo <140/90
- All ages with Diabetes <140/90
- **Non-Black
- Thiazides, ACEI, ARB, CCB
- **Black
- Thiazides, CCB
- All ages chronic kidney disease
(CKD) <140/90
- All ages chronic kidney disease
- **treat with ACEI or ARB
Can you use ACEI and ARB together?
No
