7: Anti-HTN, Diuretics - Exam 2

beta blocker impact on HTN

reduces heart rate → reduce cardiac output

diuretic impact on HTN

reduce stroke volume → reduce heart rate

ACE inhibitor impact on HTN

inhibit angiotensin I conversion → reduce vasoconstriction

RAAS pathway

renin (kidney) + angiotensinogen (liver) → angiotensin 1 + ACE (lungs)→ angiotensin 2 → thirst, vasoconstriction, aldosterone (increases water retention) → kidney

What drugs affect cardiac output (heart / circulating volume)?

cardiac factors → b blockers, Ca blockers, adrenergic / circulating volume → ACE inhibitors, diuretics

What drugs affect systemic vascular resistance (constriction/dilation)?

hormones → vasodilators, prostaglandins, ACE inhibitors, Ca blockers, angiotensin II blockers / peripheral sympathetic receptors → a1 and b blockers

HTN drug principles

BP, orthostatics (falls → Beer’s), adherence, hold at 90/60, b blockers have pulse parameters, heart rhythm

What is a diuretic?

Agents capable of increasing the volume of urine and promoting a net loss of body water, reduce edema by increasing Na+, K+, Cl+, Ca++, HCO3

diuretic side effects

acid-base imbalance/electrolyte disturbances

diuretic nursing interventions

target lab electrolyte panel

diuretic dynamics

increase glomerular filtration, decreased tubular reabsorption

osmotic diuretic dynamics

inhibit H2O + Na reabsorption from the descending loop

carbonic anhydrase inhibitor dynamics

inhibit HCO3, H, Na reabsorption from proximal tubule

loop diuretic dynamics

block Na/Cl reabsorption from ascending loop

thiazide diuretic dynamics

blocks Na/K reabsorption, increase Ca levels

potassium sparing diuretic dynamics

inhibit Na/K exchange in distal tubules, raises K levels

diuretic indications

edema, heart failure, HTN, kidney failure, liver failure, pulmonary edema

osmotic diuretic examples

glycol, 50% dextrose, mannitol

mannitol class

osmotic diuretic

mannitol indication

not HTN! prolonged surgery/acute renal failure, glaucoma.

mannitol dynamics

systemic agent, elevates blood plasma osmolarity drying fluid from brain, cerebrospinal fluid, eye tissues, later kidney

mannitol classes

osmotic diuretic

mannitol effects

maintain urinary output, lower intraocular pressure, lower ICP. very potent diuretic

xanthine diuretic examples

caffeine, theophylline (pulmonary)

thiazide side effects

hypokalemia (low potassium)

thiazide nursing interventions

target lab K (hypokalemia), eat more K rich foods (bananas, dark leafy greens)

hydrochlorothiazide (HCTZ) classes

thiazide diuretic

HCTZ nursing interventions

target lab GFR, administered daily

HCTZ contraindications

renal impairment, anuria, hepatic coma, hypersensitivity, gout

HCTZ adverse effects

hypokalemia, hyponatremia, hypochloremia, hypomagnesemia, hypercalcemia, increased uric acid + blood sugar, diuresis, fall risk

HCTZ interactions

digoxin, steroids (vit K), Ca (additive)

chlorthalidone

thiazide, better target organ damage, longer T1/2 than HCTZ

metolazone

thiazide, intermediate acting

indapamide

thiazide, used for CHF edema, hepatic metabolism

furosemide (Lasix) classes

loop diuretic

furosemide side effects

permanent diuretic effect, ototoxicity, dehydration, weight loss, headache, hTN, dizziness + fainting

furosemide nursing interventions

target lab k, monitor weight

furosemide interactions

hydantoins, diabetic meds, digoxin (dysrhythmia)

spironolactone, triamterene classes

K+ sparing diuretics

potassium sparing diuretic side effects

hyperkalemia, N + V, headache, fever, rash, gynecomastia (male breast enlargement), sexual dysfunction

potassium sparing diuretic contraindications

ACE inhibitors, potassium supplements (hyperkalemia)

potassium sparing diuretic nursing interventions

avoid salt and potassium, avoid use in pregnancy, avoid gout/kidney stone history

triamterene adverse effect

nephrotoxicity, kidney stones

spironolactone other uses (besides diuretic)

aldosterone antagonist, acne, PMS, hirsutism, precocious puberty

drugs that impact the RAAS cascade

ACE inhibitors, Angiotensin Receptor Blocker (ARB), Renin inhibitors

ACE inhibitor dynamics

prevent angiotensin 1 conversion, powerful vasodilator, inhibits aldosterone secretion, increases K+ levels, decrease afterload

ACE inhibitor examples

enalapril, lisinopril ( all end in -pril)

ACE inhibitor indications

HTN, CHF, prevention of renal disease

ACE inhibitor nursing interventions

no pregnancy, monitor kidney function, target lab GFR WBC

ACE inhibitor adverse effects

persistent cough, angioedema, hypotension, hyperkalemia, leukopenia

ARB dynamics

angiotensin II antagonist in arterioles, brain, kidney, myocardium, adrenal gland. decreases afterload, improves CO2 and exercise tolerance, reduces left ventricular hypertrophy (LVH)

losartan class

ARB (they all end in sartan)

losartan kinetics

peak 1 hour, daily dosing, CYP450

losartan contraindications

hypersensitivity (usually pretty clean)

losartan adverse effects

hTN, diarrhea, asthenia (weakness), dizziness, fatigue

losartan interactions

lithium, grapefruit juice, rifampin, indomethacin, fluconazole

aliskiren classes

renin inhibitor anti-HTN

aliskiren contraindications

ACE/ARB use, altered electrolyte balance (can cause significant drop)

verapamil, amlodipine, diltiazem classes

Ca+ channel blocker anti-HTN

calcium channel blocker dynamics

dilate peripheral arteries, decrease vascular resistance. decreases afterload, ventricular contraction force, heart rate

calcium channel blocker indications

HTN, also arrhythmia and migraine prophylaxis

verapamil indications

arrhythmia

verapamil kinetics

T1/2 3-7 hours, BiD/slow release

verapamil nursing interventions

B blocker interactions, digoxin, pregnancy cat C

verapamil side effects

constipation, dizziness, headache, flushing, reflex tachycardia, edema, heart block

amlodipine kinetics

T1/2 30-50 hr

amlodipine dynamics

more vasodilation, improves cardiac blood flow, good for angina

amlodipine side effect

edema, fatigue, dizziness

methyldopa classes

central adrenergic anti-HTN

methyldopa dynamics

decrease NE outflow, causes CNS depression

methyldopa nursing interventions

MAOI → hepatic failure, used in pregnancy

methyldopa side effects

orthostatic hTN, low WBC, water retention, CNS depression SE, impotence, decreased libido, etc

clonidine classes

central adrenergic anti-HTN

clonidine dynamics

suppress sympathetic outflow of NE to the heart, vagal stimulation decreases cardiac output and rate, vasoconstrictor inhibition reduces pulmonary vascular resistance (PVR)

clonidine indications

option for hot flashes and alcohol withdrawal

clonidine side effects

sympathetic, CNS depression. long term → retinal degeneration, rebound HTN

clonidine nursing interventions

must taper

doxazosin, tamsulosin classes

alpha 1 blockers

tamsulosin indication

BPH

doxazosin, tamsulosin side effects

1st dose → syncope, dizziness, incontinence

beta blocker dynamics

decrease cardiac workload, inhibits renin when high levels. african americans less responsive, chinese twice as sensitive.

hydralazine, minoxidil, nitroprusside classes

vasodilator anti-HTN

hydralazine nursing interventions

watch for systemic lupus erythematosus (SLE), neuritis

minoxidil nursing interventions

give with loop diuretic, can cause hypertrichosis, itching, Na + water retention

nitroprusside nursing interventions

given for HTN crisis, could cause cyanide toxicity, caution with HF, can increase ICP