HTN Group Study Guide

8/2/2019 HTN Group Study Guide

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Spring 2012 N3510 HYPERTENSION Ch 32

NORMAL REGULATION

Normal BP requires both systemic and local peripheral vascular effects. Arterial BP = cardiac output x systemic vascular resistance Cardiac output = total blood flow through the circulatory system in one minute.

o This is the amt. of blood pumped out of the L ventricle per beat (Stroke Volume) times theheart rate for 1 minute

Systemic vascular resistance (SVR) is the force opposing the movement of blood within the vessels. Sympathetic NS, vascular endothelium, renal system and endocrine system all contribute to BP

regulation.

HYPERTENSION

HTN: >140/90 taken on two or more separate evaluationso Normal:


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Diagnostic Studies

o Hx and PEo Urinalysiso BUN/Serum

creatinine

o Fasting blood glucoseo CBCo ECG

o Lipid profile,cholesterol,

triglycerides

Ambulatory BP Monitoring

o White Coat HTNo Measure at home or in the community (fire stations/hospital auxiliaries)o Use continuous, automated 24-hour ambulatory measurementso Use a diary of activites that may affect BP

o Diurnal Variabilityo In day-active people, BP is highest in the early morning, decreases during the day

and is lowest at night.

o If BP does not fall at night, then more target organ damage is likely.Lifestyle Modification

o Dietary changeso Restrict sodium


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Treatment lowers BP, but not too fast. Decrease BP 25% in first hour. Reduce to 160/100over 6 hrs.

Exceptions are ischemic stroke and aortic dissectiono Tx: IV vasodilators (sodium nitroprusside (Nitropress), Cardene, Corlopam is most

effective med or

o IV adrenergic inhibotrs (Labetalol)oro IV ACE inhibitors (Vasotec)o Monitor fluid volume status too

HTN Urgencyo Develops over days to weekso No evidence of target organ damageo Allow patient to sit for 20 or 30 minutes in a quiet environment

Let patient verbalize fears Answer patients questions about HTN Eliminate excessive noise in patients environment Meds: Fast acting oral agents: beta blockers (Labetalol), ACE inhibitor

(Captopril), or alpha2 agonist (Clonidine)

DRUG THERAPY

*JNC7 recommends maintaining a pressure of 140/90 or lower. 130/80 or lower for pts with DM

or kidney disease*

DO NOT need to know all of these details but good for review

Diuretics

o First line of defenseo Thiazides (Hydrodiuril)

o Inhibit sodium reabsorption in the distal convoluted tubule; increase excretion of sodium;decreases ECF; sustains a decrease in SVR

o Lowers BP moderately in 2-4 weekso S/E: fluid/electrolyte imbalances; CNS effects; GI effects; sexual impotence;

dermatologic effects (photosensitivity); decreased glucose tolerance

o Monitor for orthostatic hypotension, hypokalemia and alkalosis. Watch for digoxintoxicity. Avoid NSAIDS. Eat K+-rich foods.

o Loop Diuretics (furosemide/Lasix)o Inhibits NaCl reabsorption in ascending limb of loop of Henle; increases excretion of

sodium and chloride.

o More potent than thiazides, but of shorter duration; less effective for HTNo S/E: fluid/electrolyte imbalances (hypokalemia); ototoxicity; metabolic effects

(hyperglycemia); increased LDL and triglycerides with decreased HDLo Monitor for orthostatic hypotension and electrolyte abnormalities. Loop diuretics remain

effective despite renal nsufficiency. Diuretic effect increases at higher doses.

o Potassium-Sparing (spironolactone/Aldactone)o Reduce K+ and Na+ exchange in the distal tubules; Reduces excretion of K+, H+, Ca++

and Mg++; Inhibit the Na+ retaining and K+ excreting effects of aldosterone.

o S/E: hyperkalemia, N/V, diarrhea, headache, leg cramps, dizziness, maybegynecomastia, impotence, decreased libido, menstrual irregularis


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Adrenergic Inhibitors

o Centrally-Acting (clonidine/Catapres)o Reduces sympathetic outflow from CNS. Reduces peripheral sympathetic tone, produces

vasodilation; decreases SVR and BP.

o S/E: dry mouth, sedation, impotence, N/V, dizziness, sleep disturbance, nightmares,restlessness and depression. Bradycardia in pts with conduction disorders.

o Is used to treat hypertensive urgencies. Sudden discontinuation may cause withdrawalwith rebound HTN, tachycardia, headache, tremors, apprehension, sweating; Chew gum

or hard candy to relieve dry mouth; Avoid alcohol and sedatives. May be giventransdermally with fewer side effects and better compliance.

o Peripheral-Acting Adrenergic Antagonists (reserpine/Serpasil)o Prevents peripheral release of NE, resulting in vasodilation; lowers CO and reduces SBP

more than DBP.

o S/E: Orthostatic hypotension, diarrhea, cramps, bradycardia, delayed ejaculation,sodium/water retention; sedation, inability to concentrate; depression; nasal stuffiness.

o Do not use in pts with c/v or coronary insufficiency or in older adults; tell patient to riseslowly and wear support stockings. Hypotensive effect begins 2-3 days after meds, andlasts 7 to 10 days after stopping meds. Do not use in patients with hx of depression.

Monitor mood and mental status. Avoid alcohol and narcotics.

o Alpha-1 Adrenergic Blocker (-azosin)o Blocks alpha-1 effects producing peripheral vasodilation (decreases SVR and BP)o S/E: Hypotension dependent on volume. May produce syncope within 90 minutes of

initial dose; retention of sodium and water; cardiac arrhythmias, tachycardia, weakness,

flushing; abdominal pain; N/V and exacerbation of peptic ulcer.

o Reduced resistance to the outflow of urine in benign prostatic hyperplasia. Take drugs atbedtime (orthostatic hypotension); beneficial effects on lipid profile.

o Beta Blockers (-olol)o Reduces BP by antagonizing beta adrenergic effects. Decreases CO and reduces

sympathetic vasoconstrictor tone. Decreases renin secretion by kidneys.

o S/E: Bronchospasm, a/v conduction block; impaired peripheral circulation; nighmares;depression; weakness; reduced exercise capacity; may exacerbate heart failure; Sudden

withdrawal may cause rebound hypertension and cause ischemic heart disease.

o Moniotr pulse regularly; use with caution in diabetics because drug may mask signs ofhypoglycemia.

o Combined Alpha/Beta Blockers (labetalol/Normodyne)o Produces peripheral vasodilation and decreased heart rate.o S/E: dizziness, fatigue, N/V, dyspepsia, paresthesia, nasal stuffiness, impotence, edema.

HEPATIC TOXICITY.

o Keep patient supine during IV administration. Assess pt tolerance of upright position(severe postural hypotension) before allowing upright activities.

Direct Vasodilators (nitroglycerine/Tridil)

o Relaxes arterial and venous smooth muscle reducing preload and SVR.o S/E: Reflex sympathetic activation (tachycardia, salt/water retention); headache, nausea,

flushing, palpitation, angina; hypotension

o Use for hypertensive crises.


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Angiotensin Inhibitors

o Angiotensin-Converting Enzyme Inhibitors (ACE-Inhibitors) (-pril)o First line of defense for diabeticso Inhibit angiotensin-converting enzyme; reduce conversion of angiotensin I to angiotensin

II; prevent angiotensin II mediated vasoconstriction. Inhibits angiotensin-converting

enzyme when oral agents are not appropriate.o S/E: Hypotension, loss of taste, cough, hyperkalemia, acute renal failure, skin rash

angioneurotic edema.

o ASA/NSAIDS may reduce drug effectiveness. Diuretic enhances drug effect. Do not usewith K+-sparing diuretics. Fetal morbidity or mortality.

o Antiotensin II Receptor Blockers (ARBs) (-sartan)o Prevents action of angiotensin II and produces vasodilation and increased salt and water

excretion.

o S/E: Hyperkalemia, decreased renal function.o Full effect on BP takes 3 to 6 weeks.

Calcium Channel Blockers(-dipine)

oBlocks movement of extracellular calcium into cells, causing vasodilation and decreased SVR.

o S/E: Nausea, headache, dizziness, peripheral edema. Reflex tachycardia (withdihydropyridines). Reflex decreased heart rate; constipation.

o Use with caution in patients with heart failure. Contraindicated in patients with second- or third-degree heart block. IV use available for HTN crisis. Avoid grapefruit!

Common side effects

Orthostatic hypotension Sexual dysfunction Dry mouth Frequent voiding (take diuretics earlier

in the day to avoid nocturia) Sedation (take med in the evening)

BP is lowest during the night and highestafter awakeningtake med with 24-hour

duration as early in the morning as

possible.

Lack of Responsiveness to Therapy

o Costo Instructions not given

or misunderstood

o Inadequate ptteaching

o Side effectso Dementia

o Inconvenient dosingo Dosage too lowo Inappropriate comboo Rapid inactivationo Drug interactionso Increasing obesityo Alcohol >1 oz/day

o Secondary HTNo Volume overload

(inadequate diuretics,

excess sodium intake;

fluid retention; renaldamage)

o Pseudohypertension

Documents

HTN Group Study Guide