• Alpha2-adrenergic receptor stimulators (agonists)/clonidine
o Stimulate alpha2-adrenergic receptors in the brain
o Decrease sympathetic outflow from
... [Show More] the CNS, decrease norepinephrine production
o Stimulates alpha2-adrenergi receptors, thus reducing renin
o Examples: Clonidine (Catapres), Methyldopa (aldomet): used for pregnant women w/htn
• Alpha1-blockers/”azosin,”
o Block alpha1-adrenergic receptors
o Management of severe heart failure (HF) when used with cardiac glycosides and diuretics
o Some used to relieve symptoms of BPH- increase urinary flow rate
o Example: “ Azosin” (doxazosin (Cardura)
o Adverse Effects:
▪ Serious: hypotension (first dose) syncope
▪ Common: dizziness
o Nursing implications: instruct pt. to lie down after taking first dose because they may become dizzy
• Beta-blockers “olol”: First-line treatment for heart failure & HTN
o Reduce BP by reducing heart rate through beta1 blockade (block receptors for norepinhrine)
o Cause reduced secretion of renin
o Long-term use causes reduced peripheral vascular resistance
o Adverse Effects: orthostatic hypotension, bradycardia w/ reflex tachycardia, sexual dysfunction in men, possible hypoglycemia or hyperglycemia
• Angiotensin-converting enzyme inhibitor, “pril” Captopril
o Mechanism of Action:
▪ Inhibit angiotensin-converting enzyme, which is responsible for converting angiotensin I (through the action of renin) to angiotensin II
▪ Angiotensin II is a potent vasoconstrictor and causes aldosterone secretion from the adrenal glands
▪ Result in decreased systemic vascular resistance (afterload),
Vasodilation, and therefore decreased blood pressure
o Indications:
▪ First-line treatment for heart failure & HTN
▪ HF (either alone or in combination with diuretics or other drugs)
▪ Slow progression of left ventricular hypertrophy after MI (cardio protective)
▪ Renal protective effects in patients with diabetes
▪ Captopril and lisinopril can be used if a patient has liver dysfunction, unlike other ACE inhibitors that are pro-drugs
• *Pro-drugs are inactive in their administered form and must be metabolized in the liver to an active form so as to be effective
o Adverse Effects: hyperkalemia & dry, nonproductive cough
o Serious drug interaction: NSAIDs
• Angiotensin II receptor blocker “sartan” losartan (Dovan)
o Mechanism of Action:
▪ Allow angiotensin I to be converted to angiotensin II, but block the receptors that receive angiotensin II
▪ Block vasoconstriction and release of aldosterone
▪ Well tolerated, do not cause a dry cough
▪ Indications: first-line treatment for heart failure & HTN
o Adverse Effects: URI, headache
▪ May cause occasional dizziness, inability to sleep, diarrhea
• Calcium channel blockers: Amlodipine “dipine” verapamil (calan), diltiazem (cardizem)
o Mechanism of Action: cause smooth muscle relaxation by blocking the binding of calcium to its receptors, preventing muscle contraction
o Adverse effect: constipation
▪ High-fiber diet with plenty of fluids will help prevent constipation
o Indications: hypertension
▪ Angina- ch. 23
• Ischemia:
o Ischemic heart disease: Poor blood supply to the heart muscle (Atherosclerosis, Coronary artery disease)
o Myocardial infarction (MI): Necrosis, or death, of cardiac tissue, disabling or fatal
• Therapeutic Objectives
o Minimize the frequency of attacks and decrease the duration and intensity of anginal pain
o Improve the patient’s functional capacity
o Prevent or delay the worst possible outcome: MI
• Cardiac glycosides: Digoxin
o Therapeutic level: between 0.5-2ng/mL
o Digoxin doses are held and the prescriber notified if the apical pulse is 60 beats/minute
o Negative chronotropic effect decreases HR
o Digoxin immune Fab (Digifab) is the antidote for a severe digoxin overdose
▪ Required use of digitab when potassium level is above 5 mEq/L, severe sinus bradycardia that does not respond to cardiac pacing, or an overdose of more than 10 mg of digoxin.
o Avoid bran muffins when taking digoxin
o Hypokalemia increases the chance of digitalis toxicity
• Class III drugs: Amiodarone (ch. 25)
o Mechanism of action: prolonging action potential duration
o Indications: ventricular dysrhythmias
o Contraindication: hypersensitivity and bradycardia or AV block
Adverse effects: FDA black box warning: pulmonary toxicity, hepatotoxicity arrhythmia worsening-sinus bradycardia, constipation, QT prolongation, hypotension, blue-gray coloring of the skin on the face, arms, and neck
• Unclassified antidysrhythmics: Adenosine (Ch. 25)
▪ Slows conduction through the AV node
▪ Used to convert paroxysmal supraventricular tachycardia to sinus rhythm
▪ Very short half-life (less than 10 seconds)
• Flush with 20cc of normal saline
▪ Only administered as fast IV push
▪ May cause asystole for a few seconds
▪ Adverse Effects
• ALL antidysrhythmics can cause dysrhythmias!
• Hypersensitivity reactions, nausea, vomiting, diarrhea, dizziness, blurred vision, headache
▪ Assessment
• Obtain a thorough drug and medical history
• Baseline BP, P, I&O, and cardiac rhythm
• Measure serum potassium levels before initiating therapy
• Conditions that may be contraindications for use of specific drugs
• Potential drug interactions
▪ During therapy,
• Monitor cardiac rhythm, heart rate, BP, general well-being, skin color, temperature, heart and lung sounds
• Assess plasma drug levels as indicated
• Monitor for toxic effects
• Take medications as scheduled and not to skip doses or double up for missed doses [Show Less]