Chp 22 Antihypertensive Drugs Flashcards
Hypertension
A common, often asymptomatic disorder in which systolic blood pressure persistently exceeds 150 mm Hg and/or diastolic pressure exceeds 90 mm HG in patients over 60 years of age and 140/90 for patients younger than 60 and those who have chronic kidney disease or diabetes. (High blood pressure)
Blood Pressure =
CO x SVR
Cardiac output x systemic vascular resistance
What are the four stages based on BP measurements according to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure?
- Normal
- Prehypertension
- Stage 1 hypertension
- Stage 2 hypertension
Essential hypertension
elevated systemic arterial pressure for which no cause can be found; also called primary or idiopathic hypertension. (90% of all cases)
Secondary hypertension
high blood pressure caused by another disease such as renal, pulmonary, endocrine, or vascular disease. (10% of all cases)
About how many people in the United States have hypertension?
approx 70 million
What does the parasympathetic nervous system stimulate?
smooth muscle, cardiac muscle, glands
What does the sympathetic nervous system stimulate?
heart, blood vessels, skeletal muscle
What are the two divisions of the autonomic nervous system?
parasympathetic
sympathetic
What are the 7 categories of antihypertenisve drugs? (AAACDVD)
- Adrenergic Drugs
- Angiotensin-Converting Enzyme Inhibitor
- Angiotensin II Receptor Blockers
- Calcium Channel Blockers
- Diuretics
- Vasodilators
- Direct Renin Inhibitors
What are the 5 subcategories of adrenergic antihypertensive drugs?
- Centrally and peripherally acting adrenergic neuron blockers
- Centrally acting alpha2 receptor agonists
- Peripherally acting alpha1 receptor blockers
- Peripherally acting beta receptor blockers (beta blockers) - Cardioselective, Nonselective
- Peripherally acting dual alpha1 and beta receptor blockers
What do the centrally acting alpha2 receptor agonists do?
- Stimulate alpha2-adrenergic receptors in the brain
- Decrease sympathetic outflow from the CNS
- Decrease norepinephrine production
- Stimulate alpha2-adrenergic receptors, thus reducing renin activity in the kidneys
- Results in decreased blood pressure
What are two centrally acting adrenergic drugs?
clonidine and methyldopa which can be used for hypertension in pregnancy
What do peripheral alpha1 blockers/antagonists do?
block alpha1-adrenergic receptors
What are three alpha1 blockers?
doxazosin (Cardura)
terazosin (Hytrin)
prazosin (Minipress)
What do beta blockers do?
- Reduce BP by reducing heart rate through beta1 blockade
- Cause reduced secretion of renin
- Long-term use causes reduced peripheral vascular resistance
What are some examples of beta blockers?
nebivolol (Bystolic)
propranolol (Inderal)
atenolol (Tenormin)
What do dual-action alpha1 and beta receptor blockers do?
- Reduce heart rate (beta1 receptor blockade)
- Cause vasodilation (alph1 receptor blockade)
- Result in decreased blood pressure
What are some examples of dual-action alpha1 and beta receptor blockers?
carvedilol (Coreg)
labetalol
What is the centrally acting alpha2 receptor agonist Clonidine ueful in?
the management of withdrawal symptoms in opioid-dependent persons
Why are centrally acting alpha2 receptor agonists usually used only after other drugs have failed?
because of adverse effects
What are peripherally acting alpha1 receptor agonists used to treat other than hypertension?
- Tamsulosin (Flomax) is used to relieve symptoms of BPH (Benign Prostatic Hyperplasia: Age-associated prostate gland enlargement that can cause urination difficulty.)
- Management of severe heart failure when used with cardiac glycosides and diuretics
What are the adverse effects of adrenergic antihypertensive drugs?
High incidence of orthostatic hypotension Bradycardia with reflex tachycardia Dry mouth Drowsiness, sedation Constipation Depression Edema Sexual dysfunction Headaches Sleep disturbances Nausea Rash Cardiac disturbances
Hypotension
abnormally low BP
Which category of antihypertensive drugs are often used as first-line drugs for heart failure and hypertension?
Angiotensin-Converting Enzyme (ACE) Inhibitors
What may ACE Inhibitors be combined with?
a thiazide diuretic or calcium channel blocker
What are some examples of ACE Inhibitors?
captopril (Capoten) benazepril (Lotensin) enalapril (Vasotec) fosinopril (Monopril) lisinopril (Prinivil) moexipril (Univasc) quinapril (Accupril)
How do ACE Inhibitors work?
- they inhibit angiotensin-converting enzyme, which is responsible for converting angiotensin I (through the action of renin) to angiotensin II
- prevents the breakdown of the vasodilating substance bradykinin
- results in decreased systemic vascular resistance (afterload), vasodilation, and therefore decreased blood pressure.
What is angiotensin II?
it’s a potent vasoconstrictor and causes aldosterone secretion from the adrenal glands.
What are ACE Inhibitors used for in addition to hypertension?
- Heart failure (either alone or in combination with diuretics or other drugs)
- Slow progression of left ventricular hypertrophy after myocarial infarction (heart attack)
- Renal protective effects in patients with diabetes
- Drug of choice in hypertensive patients with HF and for diabetic patients
Why would captopril most likely be ordered to treat a patient for hypertension who also has a history of pancreatitis and cirrhosis?
Captopril is not a prodrug; therefore it does not need to be metabolized by the liver to be effective. This is an advantage in patients with liver disease.
Prodrugs
inactive in their administered form and must be metabolized in the liver to an active form so as to be effective
What are the 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)
- First dose hypotensive effect may occur
What is primarily affected by Angiotensin II Receptor Blockers (ARBs)?
vascular smooth muscle and the adrenal gland
What functions do ARBs block by blocking the binding of AII to the type 1 AII receptors?
vasoconstriction and the secretion of aldosterone
What adverse effect do ACE Inhibitors cause that ARBs do not?
dry cough
What are some examples of Angiotensin II Receptor Blockers (ARBs)?
losartan (Cozaar) eprosartan (Teveten) valsartan (Diovan) irbesartan (Avapro) candesartan (Atacand) olmesartan (Benicar) telmisartan (Micardis) azilsartan (Edarbi)
How do Angiotensin II Receptor Blockers (ARBs) work?
They allow angiotensin I to be converted to angiotensin II but block the receptors that receive angiotensin II.
What are ARBs used to treat?
- Hypertension
- Adjunctive drugs for the treatment of heart failure
What are the adverse effects of Angiotensin II Receptor Blockers (ARBs)?
- Upper respiratory infections
- Headache
- may cause occasional dizziness, inability to sleep, diarrhea, syspnea, heartburn, nasal congestion, back pain, fatigue
- Hyperkalemia much less likely to occur
What is an overdose of angiotensin II receptor blockers manifested by?
hyptoension and tachycardia
What is the primary use for calcium channel blockers? What else do they treat?
Primary: treatment of hypertension and angina
Also used for dysrhythmias, migraine headaches, Raynaud’s disease.
How do calcium channel blockers work?
they cause smooth muscle relaxation by blocking the binding of calcium to its receptors which prevents contraction.
What does the use of calcium channel blockers result in?
- Decreased peripheral smooth muscle tone
- Decreased systemic vascular resistance
- Decreased blood pressure
What is the primary therapeutic effect of diuretics?
decreasing the plasma and extracellular fluid volumes.
What is the result of the use of diuretics?
- Decreased preload (the initial stretching of the cardiac myocytes prior to contraction)
- Decreased cardiac output
- Decreased total peripheral resistance
- Overall decreased workload of the heart and decreased blood pressure
What are the most commonly used diuretics for hypertension?
Thiazide diuretics
What are diuretics listed as in the JNC-8 guidelines?
first-line antihypertensives
What do vasodilators act directly on?
arteriolar and/or venous smooth muscle to cause relaxation
What are some common vasodilators?
diazoxide (Hyperstat)
hydralazine HCI (Apresoline)
minoxidil (Loniten)
sodium nitroprusside (Nipride, Nitropress)
What does the use of vasodilators result in?
- Decreased systemic vascular response
- Decrased afterload (the initial stretching of the cardiac myocytes prior to contraction)
- Peripheral vasodilation
What are vasodilators used to treat?
Hyptertension (may be used in combination with other drugs)
Which two vasodilators are reserved for the management of hypterensive emergencies?
sodium nitroprusside and intravenous diazoxide
What should be monitored during the use of antihypertensive drugs?
BP
What can happen if a patient abruptly stops using antihypertensive drugs?
rebound hypertensive crisis and possibly stroke
Why should oral forms of antihypertensive drugs be taken with food?
so that absorption is more gradual and effective
What else should patients who are taking antihypertensive drugs be sure to watch?
- diet, stress level, weight, and alcohol intake
- avoid smoking and high sodium foods
Why should patients taking antihypertensive drugs change positions slowly?
to avoid syncope (temporary loss of consciousness caused by a fall in blood pressure) from postural hypotension
What adverse effects should patients taking antihypertensive drugs report?
- unusual shortness of breath
- difficulty breathing
- swelling of the feet, ankles, face, or around the eyes
- weight gain or loss
- chest pain
- palpitations
- excessive fatigue
What adverse reaction could affect male patients taking antihypertensive drugs?
impotence
