Exam 2 topic 6 antihypertensive drugs Flashcards
Adrenergic drugs
Large group of antihypertensive drugs. The alpha blockers and combined alpha/beta blockers.
Adrenergic drugs mechanism of action
Have central action (in the brain) or peripheral action (at the heart and blood vessels).
-Adrenergic neuron blockers (central and peripheral)
-Alpha 2 receptor agonists (central)
-Alpha 1 receptor blockers (peripheral)
-Beta receptor blockers (peripheral)
-Combination alpha 1 and beta receptor blockers (peripheral)
Action: stimulation of SNS leads to an increase in HR and force of contraction, constriction of blood vessels, & release of renin from kidneys, resulting in hypertension
What are the centrally acting adrenergic drugs and their mechanism of action
Clonidine and methyldopa stimulate the alpha 2-adrenergic receptors in the brain.
- receptor stimulation reduces sympathetic outflow & results in lack of norepinephrine production, reducing BP
- stimulation also affects the kidneys, reducing activity of renin
Define renin
The hormone and enzyme that converts the protein precursor of angiotensin II (AII), a potent vasoconstrictor that raises BP
Mechanism of action for alpha 1 blockers in the periphery
Drugs: Doxazosin (Cardura)
Work by blocking the alpha 1-adrenergic receptors
-when alpha 1-adrenergic receptors are stimulated by circulating norepinephrine, they produce increased BP, thus when they are blocked by these drugs BP decreased
The drug effects of the alpha 1 blockers (Doxazosin [Cardura]) are primarily related to?
Their ability to dilate arteries and veins, which reduces peripheral vascular resistance and subsequently decreases BP. This produces a marked decrease in the systemic and pulmonary venous pressures and an increase in cardiac output
-they also increase urinary flow rates and decrease outflow obstruction by preventing smooth muscle contractions in the bladder neck and urethra which can be beneficial in cases of benign prostatic hyperplasia (BPH)
Beta blockers mechanism of action
-Drugs: Metoprolol (Lopressor), Nebivolol (Bystolic)
Act in the periphery, their antihypertensive effects are related to their reduction of the HR through beta 1 receptor blockade.
- Also cause reduction in secretion of renin which in turn reduces both AII-mediated vasoconstriction and aldosterone-mediated volume exspansion
- long term use reduces peripheral vascular resistance
Adrenergic drugs indications
Tx of hypertension, either alone or in combination w/other hypertensive drugs
- various forms of glaucoma may also respond to Tx
- alpha 1 blockers (Doxazosin [Cardura]) used to relieve symptoms associated w/BPH. Also proved effective in management of severe heart failure when used with cardiac glycosides
Contraindications for adrenergic antihypertensive drugs
- known drug allergy
- acute heart failure
- concurrent use of monoamine oxidase inhibitors
- peptic ulcer
- severe liver or kidney disease
- Asthma contraindication for use of any noncardioselective beta blocker
Adverse effects for adrenergic antihypertensive drugs
- bradycardia w/reflex tachycardia
- postural and postexercise hypotension
- dry mouth
- drowsiness
- dizziness
- depression
- edema
- constipation
- sexual dysfunction
- HA
- Sleep disturbances
- nausea
- rash
- palpitations
- Orthostatic hypotension w/those taking alpha blockers
- abrupt discontinuation of centrally acting alpha 2 receptor agonists=rebound hypertension (sudden & very high elevation of BP)
- nonselective blocking drugs associated w/bronchoconstriction & metabolic inhibition of glycogenolysis in liver
Any change in the dosing regimen for cardiovascular medications should be?
Undertaken gradually and with appropriate patient monitoring and follow-up
- abrupt dosing changes of cardiovascular medications, either up or down, can be especially hazardous for the patient
- some drugs can cause disruptions in blood count as well as serum electolyte levels and renal function
- periodic monitoring of WBC count, serum potassium, sodium and creatinine levels is necessary
Antihypertensive Adrenergic drugs interactions
-Can cause additive CNS depression when taken w/alcohol, benzodiazepines, and opioids
Alpha 2-adrenergic receptor stimulators (agonists) Clonidine (Catapress)
- Mostly used & is prototypical drug for this class
- may be used as adjunct drugs in Tx of HTN after others failed, may be used in conjunction w/other antihypertensives such as diuretics
Clonidine (Catapress)
- decrease BP
- management of opioid withdrawal
- better safety profile than other centrally acting adrenergics & advantage of being available in several dosage formulations, including topical and oral
- when patch used, remove old patch before applying new one
- DON’T discontinue abruptly, will lead to severe rebound hypertension
- contraindicated in pt’s with shown hypersensitivity reactions to it
Alpha 1 blockers (Doxazosin (Cardura, Cardura XL)
Contraindicated in pt’s who have shown hypersensitivity to them.
- pregnancy category C drugs
- ONLY oral preparations
(Doxazosin (Cardura, Cardura XL)
Alpha 1 blocker
- reduces peripheral vascular resistance & BP by dilating both arterial & venous blood vessels
- available in immediate & extended release formulations
- when drug released from extended-release form, matrix of capsule is expelled in stool (educate pt’s about this & reassure that active drug has been absorbed, because confusion could cause pt’s to take more than prescribed)
Beta receptor blocker (Nebivolol)
New, released in 2008
- Beta 1-selective beta blocker approved for hypertension
- also for Tx of heart failure
- similar to other beta 1 selective blocker but in additon to blocking beta 1 receptors, also produces vasodilation, resulting in decrease SVR
- causes less sexual dysfunction
- do NOT stop abruptly, but tapered over 1-2 weeks
Nursing process for antihypertensive drugs as indicated by the National Institutes of Health
Switched from stepped approach to a guideline-based approach to the diagnosis and Tx of HTN
Nursing assessment for antihypertensive drugs
- obtain thorough health history
- head-to-toe
- measure/document BP, pulse, respirations, pulse oximetry
- ECG
- Monitor lab tests (serum sodium, potassium, chloride, mg, C+, CBC/platelet count, renal function studies (BUN, serum, urinary creatinine levels; C-reactive protein (CRP) to measure systemic inflammation; cholesterol/lipid profiles; hepatic function studies (serum levels of ALT & AST)
- if MI suspected, additional lab tests include arterial blood gases (ABG’s); erythrocyte sedimentation rate (ESR); specific cardiac biomarkers/enzymes (tropinins; usually elevated w/in 4-6 hrs after MI, reliable indicator up to 14 days); creatine phosphokinase-myocardial band (CPK-MB), LDH, myoglobin levels
- noninvasive ophthalmoscopic examination of eye structures by advanced practice allows easy visualization of structures impacted by HTN (if present, narrowing of blood vessels in eyes, oozing of fluid, spots on retina, swelling of macula & optic nerve, bleeding of back of eye)
- prevented by controlling BP/Tx of hypertension
- use caution in older adults/chronic illnesses
Nursing assessment for alpha-adrenergic agonists
- BP, pulse, weight before & during Tx (due to strong vasodilation properties & subsequent hypotensive AE)
- these may be associated w/edema & fluid retention so assess heart/breath sounds & I&O, & dependent edema
- alpha-adrenergic antagonists use cautiously due to potential for hypotension-induced dizziness & syncope
Nursing assessment for adrenergic drug Doxazosin
First-dose orthostatic hypotension may occur w/in 2-6 hours; therefore, carefully assess blood pressures (supine & standing) & measure corresponding pulse rates before first dose & 2-6 hours afterward subsequent increase in dosing
When any antihypertensive drug is used, the nurse should?
Measure BP & pulse rates (supine & standing), & assess for cautions, contraindications, drug interactions
- with centrally acting alpha blockers, also assess WBC counts, serum potassium & sodium levels, & level of protein in urine (to identify proteinuria)
- note route of administration specified in the drug order because of concerns associated w/diff routes (e.g clonidine transdermal patches, assess the skin for rashes,redness, drainage, or broken integrity prior to application)
Before administering beta blockers the nurse should?
Review their mechanism of action because of risk for complications in certain patient populations
- if drug is nonselective beta blocker, it blocks both beta 1 & 2 receptors & will have both cardiac and respiratory effects, whereas if drug is beta 1-blocking drug, the cardiac system will be affected (pulse rate & BP decrease) but no affect on beta 2. This limits concern regarding respiratory problems (e.g. bronchoconstriction). Therefore if pt needs beta blocker but has restrictive airway problems, beta 1 recommended (to avoid bronchoconstriction). If no history of respiratory illness/concerns, the nonselective beta blockers may be effective
- for those w/heart failure, beta blockers have a negative inotropic effect on the heart (decreased contractility); their use would lead to worsening of heart failure, which calls for a completely diff. class of antihypertensives
- assess BP and apical pulse rate immediately before EACH dose. If systolic BP <90mmHg or pulse rate is <60 beats/min, notify prescriber because of risk of AE (hypotension, bradycardia). Drug would usually be withheld
- assess breath/heart sounds BEFORE & DURING drug therapy
Patient centered care: cultural implications for antihypertensives drug therapy
- Both thiazide-type diruetics & calcium channel blockers (CCBs) recommended first line therapy for management in BLACK patients
- ASIAN pt’s receiving CCB report highest rates of control for HTN. ARBs & ACEIs have tolerability &/or adherance advantages
- low diuretics use in ASIANS related to occurrance of serious AE (hypokalemia)
- many ASIAN pt’s will require @least two antihypertensive medications to achieve BP control. Single pill combinations improve convenience & simplicity of regimens
- Tx w/thiazide diuretic, CCB, or ARB for isolated systolic HTN recommended as first-line therapy in the Taiwanese
- due to high rate of cardiac morbidity in Hispanic Americans, ACEIs & ARBs are useful in this population in protecting against end-organ damage secondary to HTN
Focus nursing goals for antihypertensive therapy on educating patient, family, and/or caregiver about the critical importance of adequate management to prevent end organ damage. Goals must include?
- Making sure pt understands the nature of the disease, its symptoms & Tx
- importance of adhering to Tx regimen
- come to terms w/diagnosis as well as w/fact that there is no cure for the disease & Tx will be lifelong
- emphasize influence of chronic illness & importance of nonpharmacologic therapy, stress reduction, follow-up care plan
- plan for ongoing assessment of BP, weight, diet, exercise, smoking habits, alcohol intake, compliance w/therapy, & sexual function
Pressure mnemonic for antihypertensive drugs
Pressure (blood) monitor Rise slowly to reduce orthostatic hypotension Eating must be considered (diet) Stay on medications Skipping or stopping is a no-no Undesirable responses Remind to exercise, no alcohol Eliminate smoking; educate
Antihypertensives are often associated w/multiple AE’s that may impact pt’s energy level, self-concept, and/or sexual integrity. These AE’s may lead patients to?
Abruptly stop taking the medication. Inform pt’s that any abrupt withdrawal is a serious concern because of risk for REBOUND HYPERTENSION (sudden & very high elevation of BP)
-this places pt at risk for a cerebrovascular accident or other cerebral or cardiac AE’s
With ALL hypertensives there is a risk for?
Rebound hypertension (with abrupt withdrawal), and prevention of this through patient education is critical to pt safety
Because of the potential for drug-related orthostatic hypotensive effects, patients taking alpha-adrenergic agonists will need to monitor?
Their BP & pulse rate at home or have these parameters measured by a family member (NOT ones in grocery stores)
Alpha-adrenergic antagonist drugs are associated with?
First-dose syncope, so, to avoid injury, advise patients to remain supine for the first dose of the drug
- may take 4-6 weeks to take full effect. Educate about this delay
- pt needs continuous monitoring for dizziness, syncope, edema & other AE’s (SOB, exacerbation)
- Diuretics are adjunctive therapy to minimize AE’s of edema, may lead to more dizziness & electrolyte problems
Centrally acting alpha blockers require the same type of nursing interventions as other alpha blockers; however, as their name indicates, the mechanism of action of these drugs is?
Central, so AE’s are often more pronounced (e.g hypotension, sedation, bradycardia, edema)
The beta blockers are either nonselective (block both beta 1 and 2 receptors) or cardioselective (block mainly beta 1 receptors) with any beta blocker what should we educate the pt on?
Careful adherence to drug regimen is critical to pt safety.
- pt’s taking beta blockers may experience an exacerbation of respiratory diseases such as asthma, bronchospasm, and COPD (because of increased bronchoconstriction due to beta 2 blocking) or an exacerbation of heart failure (because of drugs negative inotropic effects, i.e. decreased contractility due to beta 1 blocking)
- provide clear and concise instructions about reporting AE’s & instructions for taking BP & pulse rates
- if beta 1 blocker causes SOB, most likely due to edema and/or exacerbation of heart failure
- any dizziness, postural hypotension, edema, constipation, or sexual dysfunction needs to be reported to the prescriber immediately
Always base nursing interventions on a thorough assessment and plan of care that also includes consideration of the patient’s cultural and ethnic group. This is particularly important with?
Antihypertensives, because research studies have documented differences in responses to antihypertensives among different racial & ethnic groups
Because patients with HTN are at a high risk for cardiovascular injury, it is critical for them to?
Adhere to both their pharmacologic and nonpharmacologic Tx regimens
-monitor for AE’s & toxic effects to identify potentially life-threatening complications
The most important aspect of the evaluation for antihypertensives is?
Collecting data and monitoring patients for evidence of controlled BP.
- BP must maintained at values lower than parameters established by JNC or below the levels for prehypertension (120-139/80-89). If pt has diabetes mellitus or kidney disease, BP is lower
- measure BP at periodic intervals
- pt education about self-monitoring important
- prescriber will measure fundus of the eye (changes in fundus are more reliable indicator of long-term effectiveness of Tx than blood pressure readings because changes in vasculature of the eye caused by high BP)
- continually monitor pt for development of end-organ damage
- Counsel and constantly monitor male pt’s for complaints of sexual dysfunction
What happens when patients abruptly stop taking antihypertensives
They are at a high risk for rebound hypertension & possible stroke or other complications
What are the therapeutic effects of antihypertensives
Improvement in BP & in the disease process
- return to a normal baseline level of BP w/improved energy levels and decreased s/s of HTN (less edema, improved breath sounds, no abnormal heart sounds, capillary refill <5 seconds, less SOB)
- monitor AE
Antihypertensives patient education (General)
- take as ordered
- adherence to regimen/diet
- pt monitor stress levels & use biofeedback, imaginary massage
- avoid smoking, excessive alcohol intake/exercise, hot climates, saunas, hot tubs, hot environment (heat precipitates vasodilation & leads to worsening hypotension)
- frequent lab tests
- keep out of reach of children (extreme toxicity). Transdermal patches check on, dont let fall off)
- medical alert bracelet (house, car, etc.)
- record BP/daily weights in journal. (Weights done morning before breakfast, at same time, same amount of clothing). Report an increase in weight by 2 lbs or more over a 24-hr period or 5lbs in a week
- educate to inform all health care providers (dentists, surgeon) of taking antihypertensives
- careful purposeful, & cautious changing of positions encouraged due to AE of postural hypotension and associated risk for dizziness, lightheadedness, and possible fainting and falls
- keep adequate supply of medications on hand
- schedule periodic eye exam (Q6 months)
- w/successful therapy conditions will improve, but NEVER stop abruptly. Life-long therapy
- saliva substitutes, use of sugar-free hard candy/gum and forcing fluids helps with dry mouth
- forcing fluids and increasing dietary fiber may help w/preventing constipation
- sexual dysfunction
- may lead to depression and to report any change in emotional status to the prescriber
Alpha-Adrenergic agonists patient teaching
- first-dose syncope, avoid conditions/situations/drugs that would exacerbate this
- careful w/driving or anything involving alertness
- report dizziness, palpitations, orthostatic hypotension
- centrally acting alpha blockers affect sexual dysfunction inform pt of these AE’s, report if problematic
- transdermal patches of clonidine are applied to non-hairy areas, rotate sites. Clean off residual w/lukewarm water & thoroughly dry area
