Chapter 22: Antihypertensive Drugs Flashcards
Normal Blood Pressure
<120 mm Hg systolic and
<80 mm Hg diastolic
Pre-hypertension
120-139 mm Hg systolic or
80-89 mm Hg diastolic
Hypertension Stage 1
140-159 mm Hg systolic or
90-99 mm Hg diastolic
Hypertension Stage 2
Greater than or equal to 160 mm Hg systolic or Greater than or equal to 100 mm Hg diastolic
Types of Hypertension
- Primary
- Secondary
- Isolated Systolic
- Malignant
Risk Factors for Hypertension
Modifiable (lack of exercise, smoking, diet, weight) and Unmodifiable (age, gender, genetics)
Hypertension can cause
Endothelial injury and tissue ischemia to the vessel walls → inflammation
Hypertension is a
silent disease
signs and symptoms occur due to: specific for the organs or tissues affected.
Complications of hypertension
- cerebrovascular accident -stroke
- myocardial infarction -heart attack
- renal failure
- aortic dissection
Lifestyle changes that can prevent hypertension
- weight reduction
- moderate alcohol intake
- regular physical activity
- stress reduction (biofeedback, relaxation)
- smoking cessation
- change in diet
Seven Main Categories of Antihypertensive Drugs:
- diuretics
- adrenergic drugs
- vasodilators
- angiotensin-converting enzyme (ACE) inhibitors
- angiotensin receptor blockers (ARB’s)
- calcium channel blockers (CCBs)
- indirect renin inhibitors
secondary hypertension
high blood pressure caused by another disease such as renal, pulmonary, endocrine or vascular disease
2 divisions of the autonomic nervous system
parasympathetic and sympathetic nervous system
Stimulation of the ANS is controlled by
the neutrotransmitters acetylcholine and norepinephrine.
Receptors in the PSNS are called
muscarinic or cholinergic receptors
Receptors in the SNS are called
adrenergic or noradrenergic receptors (ex. alpha or beta receptors)
Physiologic activity at muscarinic receptors are stimulated by and inhibited by ….
stimulated by acetylcholine and cholinergic agonist drugs.
inhibited by cholinergic antagonists drugs.
Physiologic activity at adrenergic receptors are stimulate by and inhibited by..
stimulated by norepinephrine, epinephrine, and adrenergic agonists.
inhibited by antiadrenergics
Adrenergic drugs
drugs that stimulate the SNS
Five specific adrenergic drug subcategories
- adrenergic neuron blocks (central and peripheral)
- the alpha2 receptor agonists (central)
- the alpha1 receptor blockers (peripheral)
- the beta receptor blockers (peripheral)
- combination alpha 1 and beta receptor blockers (peripheral)
Each of these subcategories of drugs can be described as
having central action (in the brain) or peripheral action (at the heart and blood vessels)
Stimulation of the SNS leads to
- an increase in heart rate and force of contraction
- the constriction of blood vessels
- the release of renin from the kidneys
resulting in hypertension
Alpha2 receptor agonists
-centrally acting
Mechanism of Action: Alpha2 receptor agonists
- Stimulate alpha2-adrenergic receptors in the brain,
- Decreases sympathetic outflow from the CNS
- Decrease norepinephrine production,
- Stimulate alpha2-adrenergic receptors → reduce renin activity in the kidneys,
- Result in decreased BP.
Uses for alpha2 receptor agonists
-hypertension
Clonidine
useful in the management of withdrawal symptoms in opioid-dependent persons
What are the alpha2 receptor agonists?
clonidine and methyldopa (HTN in pregnancy)
Mechanisms of Action: Alpha1 receptor blockers
- Block alpha1 receptors (cause vasodilation of arteries and veins),
- Reduce peripheral vascular resistance,
- Result in decreased BP.
Uses for alpha1 receptor blockers
- HTN
- relief of BPH symptoms
- congestive heart failure
What are the alpha1 receptor blockers?
doxazosin, terazosin
prazosin
Mechanism of Action: beta receptor blockers
- Block beta1 receptors,
- Reduce heart rate,
- Reduce secretion of renin (reduces secretion of AT2),
- Result in decreased BP.
Uses for beta receptor blockers
angina and conduction problems
What are the beta receptor blockers?
atenolol, propranolol, metoprolol, nebivolol, nadolol, sotalol
Mechanism of Action: dual alpha1 and beta blockers
- Block beta1 receptors
- Reduce heart rate,
- Reduce secretion of renin (reduces secretion of AT2).
- Block alpha1 receptors (cause vasodilation of arteries and veins),
- Result in BP.
What happens when you block alpha1 receptors?
causes vasodilation of arteries and veins
Uses for dual alpha1 and beta blockers?
- hypertension
- congestive heart failure
What are the dual alpha1 and beta blockers?
carvedilol, labetalol
What are the most common adverse effects of adrenergic drugs?
- bradycardia w/ reflexive tachycardia
- orthostatic hypotension
- dry mouth
- drowsiness, sedation
- constipation
- depression
- edema
- sexual dysfunction
- fatigue
What are other adverse effects of adrenergic drugs?
headaches, sleep disturbances, nausea, rash, cardiac disturbances (palpitations), others
methyldopa
alpha2-adrenergic receptor drug used to treat hypertension in pregnancy
Mechanism of Action: ACE inhibitors
-Inhibit angiotensin converting enzyme (ACE)
-Converts Angiotensin I to Angiotensin II
-Prevent the breakdown of bradykinin
(vasodilating substance)
What are the effects of ACE inhibitors?
decreased afterload, vasodilation = decreased BP
Uses for ACE inhibitors
-hypertension, congestive heart failure
-post myocardial infarction (cardioprotective)
-renal protective effects in patients with diabetes
+
ACE inhibitors: Drugs
captopril, benazepril, enalapril, fosinopril, lisinopril, quinapril, moexipril
ACE inhibitors are the drugs of choice in
- hypertensive patients with congestive heart failure
- diabetic patients
Prodrugs
- a drug that is inactive in its given form and must be metabolized to its active from in the body.
- generally by the liver, to be effective
Captopril and lisinopril
are NOT prodrugs.
-can be used if a patient has liver dysfunction, unlike other ACE inhibitors that are prodrugs.
Adverse Effects of ACE inhibitors
- Fatigue
- Dizziness
- Headache
- Mood changes
- Impaired taste
- Possible hyperkalemia
- Dry, nonproductive cough, which reverses when therapy is stopped
- Angioedema: rare but potentially fatal
Mechanism of Action: Angiotensin II Receptor Blockers (ARBs)
Block vasoconstriction and release of aldosterone = BP
Uses of ARBs
- hypertension
- adjunctive drugs for the treatment of congestive heart failure
- adjunctive drugs for patients with diabetes (to protect their kidneys)
What are the Angiotensin II Receptor Blockers (ARBs)?
iosartan, valsartan, irbesartan, candesartan, olmesartan, telmisartan
Mechanism of Action: Calcium Channel Blockers
- Block binding of calcium to its receptors, preventing muscle contraction
- Smooth muscle relaxation, preventing muscle contraction
Use of Calcium Channel Blockers results in
- decreased peripheral smooth muscle tone
- decreased systemic vascular resistance
- decreased blood pressure
Uses for Calcium Channel Blockers
- angina
- hypertension
- dysrhythmias
What are the calcium channel blockers?
amlodipine, nifedipine, felodipine, diltiazem, verapamil
Adverse effects of calcium channel blockers
- Constipation**
- Dizziness
- Facial flushing
- Dry mouth
- Headache
- Edema of ankles and feet**
- fatigue**
- erectile dysfunction **
**most likely to occurfursing i
Mechanism of Action: Vasodilators
- Directly relax arteriolar and/or venous smooth muscle
- Results in decreased BP
Uses for Vasodilators
treats hypertension
What are the vasodilators?
diazoxide, hydralazine HCl, minoxidil, sodium nitroprusside
Before giving antihypertensive drugs, what should the nurse do?
- before beginning therapy, obtain a thorough health history and head-to-toe physical examination
- assess for contraindications to specific antihypertensive drugs
- assess for conditions that require cautious use of these drugs
What should the nurse educate and instruct the patients to do when it comes to doses of antihypertensive drugs?
- educate patients about the importance of not missing a dose and taking the medications exactly as prescribed
- instruct patients to check with physician for instructions on what do do if dose is missed
If a dose is missed, the patient should
never double up on doses
During antihypertensive drug therapy, the nurse should
-monitor BP; instruct patients to keep a journal of regular BP checks
Why should a nurse inform patients that antihypertensive drugs should not be stopped abruptly?
because it may cause a rebound hypertensive crisis and perhaps lead to a stroke
During antihypertensive drug therapy, the nurse should
- monitor BP; instruct patients to keep a journal of regular BP checks
- monitor for adverse effects and for toxic effects
- monitor for therapeutic effects
The nurse should always administer IV forms of antihypertensive drugs
with extreme caution and using an IV pump
The nurse should remind patients that
medication is only one part of therapy.
Because medications are only one part of the treatment, the nurse should encourage and instruct the patient to
- watch their diet, stress level, weight and alcohol intake
- instruct patients to avoid smoking and eating food high in sodium
- encourage supervised exercise
Why should the nurse teach patients to change positions slowly?
to avoid syncope from postural hypotension
The nurse should instruct the patient to report any
- shortness of breath
- difficulty breathing
- swelling of the feet, ankles, face or around the eyes
- weight gain or loss
- chest pain
- palpitations
- excessive fatigue
Male patients may not be aware that taking antihypertensive drugs can cause
impotence (inability to achieve an erection or orgasm) which may influence compliance with the drug therapy
If patients are experiencing serious adverse effects or if they believe the dose or medications needs to be changed, they should…
contact their physician immediately
Factors that may aggravate low blood pressure, leading to fainting and injury include
- hot tubs, showers, or baths
- hot weather
- prolonged sitting or standing
- physical exercise
- alcohol ingestion
Patients should not take any other medications, including over-the-counter drugs without
first getting the approval of their physician
there will be questions on statistics “lifes simple 7”
….
Theories for Hypertension
Sympathetic Nervous System, Renin Angiotensin Aldosterone System, defect in renal sodium excretion, interaction involving insulin resistance
Primary hypertension
no known cause. Based on lifestyle.
Isolated systolic hypertension
systolic BP increases while diastolic remains normal.
common in the elderly
malignant hypertension
very rare, but can be deadly
increase in systolic BP
any changes to the preload, afterload and contractility of the heart can
effect BP
Uses for Beta blockers
HTN, congestive heart failure, migraines
Adverse Effects of ARB’s
- upper respiratory infections
- headache
- may cause occasional dizziness, inability to sleep, diarrhea, dyspnea, heartburn, nasal congestion, back pain, fatigue
- hyperkalemia less likely to occur than in ACE
- first dose hypotension
- angioedema
