Chapter 44 - Drugs Acting on the Renin Angiotensin-Aldosterone System

What are the adverse effects of ARBs?

-Angioedema -fetal harm -renal failure

How do Angiotensin 2 Receptor Blockers (ARBs) work?

-Block access of angiotensin 2 -Cause dilation of arterioles and veins -Prevent angiotensin 2 from inducing pathologic changes in cardiac structure -Do NOT increase levels of bradykinin

What are the actions of angiotensin 2?

-Causes Vasoconstriction when converting from angiotensin 1 to angiotensin 2. -Release of aldosterone -Alteration of cardiac and vascular structure

What are adverse effects of ACE inhibitors?

-First-dose hypotension -Fetal injury -Cough -angioedema Hyperkalemia -Renal failure -Neutropenia

What are the therapeutic uses of ACE Inhibitors?

-Hypertension -Heart failure -Myocardial infarction -Diabetic and nondiabetic nephropathy -Prevention of MI, stroke, and death

What are the therapeutic uses for ARBs?

-Hypertension** -Heart failure** -Myocardial infarction** -Use in patients whom are unable to tolerate ACE inhibitors

What do Angiotensin-Converting Enzyme (ACE) Inhibitors do?

-Reduce levels of angiotensin 2 -Increase levels of bradykinin

What are some drug interactions to be aware of when using ACE inhibitors?

-diuretics -antihypertensive agents -Drugs that can raise K levels -Lithium -Nonsteroidal antiinflammatory drugs (NSAIDs; motril, ibuprohen, aspirin, tylenol)

What is the suffix for ACE Inhibitors?

-pril

What is angioedema?

ACE inhibitors can cause angioedema, a potentially life-threatening reaction. If patients report edema of the tongue, lips, or eyes, emergency care should be sought immediately. The patient must never take ACE inhibitors again.

How is angiotensin 1 converted to angiotensin 2?

As Angiotensin 1 passes through the lungs, the angiotensin converting enzyme converts the angiotensin 1 to angiotensin 2.

How is angiotensinogen converted to Angiotensin 1?

As angiotensinogen passes through the kidney and comes into contact with renin, it is converted.

True or false: All ACE Inhibitors may be administered with food.

False. Captopril and moexipril must be administered an hour before eating.

Where is renin synthesized?

In the kidneys

Where is angiotensinogen synthesized?

In the liver

Where is angiotensin converting enzyme released?

In the lungs

With the exception of enalaprilat, how are ACE inhibitors administered?

Orally

What is the action of aldosterone?

Regulates blood volume and blood pressure

The nurse has just administered the initial dose of enalapril [Vasotec] to a newly admitted patient with hypertension. What is the priority nursing intervention over the next several hours? A) Monitor blood pressure. B) Check the heart rate. C) Auscultate lung sounds. D) Draw a potassium level.

The answer is A. First-dose hypotension is a serious potential adverse effect of ACE inhibitors, such as enalapril. Monitoring the blood pressure is the priority nursing intervention. If hypotension develops, the nurse will place the patient in the supine position and possibly increase intravenous fluids. The other interventions may be appropriate for this patient; however, in the hours immediately after the first dose of an ACE inhibitor, monitoring of the blood pressure is most important.

The nurse teaches a patient about benazepril [Lotensin], an ACE inhibitor. Which statement by the patient requires an intervention by the nurse? A) "I use NoSalt instead of salt to season foods." B) "I eat sweet potatoes once or twice a week." C) "I drink 4 ounces of prune juice each morning." D) "I like asparagus because it's high in vitamin K."

The answer is A. An adverse effect of angiotensin-converting enzyme (ACE) inhibitors (for example, benazepril) is hyperkalemia. Significant potassium accumulation is usually limited to patients taking potassium supplements, salt substitutes (which contain potassium), or a potassium-sparing diuretic. Patients should be instructed to avoid potassium supplements and potassium-containing salt substitutes unless they are prescribed. Sweet potatoes and prune juice are foods high in potassium; asparagus is high in vitamin K. Foods high in vitamin K are restricted for patients who are prescribed warfarin [Coumadin].

The renin-angiotensin-aldosterone system plays an important role in maintaining blood pressure. Which compound in this system is most powerful at raising the blood pressure? A) Angiotensin I B) Angiotensin II C) Angiotensin III D) Renin

The answer is B. Angiotensin II is a potent vasoconstrictor. It participates in all the pathways regulated by the renin-angiotensin-aldosterone system. Angiotensin I is a precursor to angiotensin II; angiotensin III is formed by degradation of angiotensin II and is less potent. Renin catalyzes the conversion of angiotensinogen to angiotensin I.

A patient is prescribed lisinopril [Prinivil] 40 mg by mouth once a day for hypertension. For which therapeutic effect will the nurse monitor? A) Slowing of the heart rate B) Decrease in blood pressure C) Symptoms such as dizziness and fainting D) Pulse oximetry oxygen saturation of 100%

The answer is B. The therapeutic effect of ACE inhibitors is to reduce blood pressure in patients with hypertension. ACE inhibitors do not affect patients' heart rate. Dizziness and fainting are symptoms of hypotension. ACE inhibitors do not affect oxygen saturation.

The nurse is caring for a patient with bipolar disorder treated with lithium [Eskalith]. The patient has a new prescription for captopril [Capoten], an ACE inhibitor, for hypertension. The combination of these two drugs makes which assessment particularly important? A) Potassium level B) Lithium level C) Creatinine level D) Blood pressure

The answer is B. ACE inhibitors, such as captopril, can cause lithium accumulation. Lithium levels should be monitored on a regular basis. ACE inhibitors can cause hyperkalemia, renal insufficiency in some patients, and hypotension. However, the combination of lithium and captopril would not increase the risk of these effects.

A patient is prescribed lisinopril [Prinvil] as part of the treatment plan for heart failure. Which finding indicates the patient is experiencing the therapeutic effect of this drug? A) + 2 edema of the lower extremities B) Potassium level of 3.5 mEq/L C) Crackles in the lungs are no longer heard D) Jugular vein distention

The answer is C. Because ACE inhibitors promote venous dilation, they provide the therapeutic effect of reducing pulmonary congestion and peripheral edema. Absence of previously heard crackles would be an indicator of effectiveness. Edema and jugular vein distention are manifestations of heart failure. A potassium level of 3.5 mEq/L is a normal value.

A patient who is taking spironolactone [Aldactone] is prescribed losartan [Cozaar], an ARB. The nurse should take which action? A) Assess for symptoms of hyperkalemia. B) Observe for a hypertensive crisis. C) Administer the medications as scheduled. D) Evaluate for first-dose hypotension.

The answer is C. These medications may be administered together without serious drug interactions. Spironolactone is a potassium-sparing diuretic, and losartan is an angiotensin II receptor blocker (ARB). The hypotensive effects of ARBs are additive with those of other antihypertensive drugs. When an ARB is added to an antihypertensive regimen, dosages of the other drugs may require reduction. The patient would be observed for hypotension (not first-dose hypotension).

The nurse is caring for a patient with renal artery stenosis who has been prescribed benazepril [Lotensin], an ACE inhibitor. Which laboratory result indicates an adverse effect of this drug? A) Potassium level of 3.2 mEq/L B) Blood glucose level of 180 mg/dL C) Serum creatinine level of 2.3 mg/dL D) Uric acid level of 10 mg/dL

The answer is C. Patients with bilateral renal artery stenosis are at increased risk for renal insufficiency and failure with angiotensin-converting enzyme (ACE) inhibitors, such as benazepril. ACE inhibitors do not typically cause hypokalemia, hyperglycemia, or hyperuricemia.

The nurse is evaluating the teaching done with a patient who has a new prescription for fosinopril [Monopril], an ACE inhibitor. Which statement by the patient indicates a need for further teaching? A) "I can take this medicine with breakfast each morning." B) "I will call if I notice a rash or wheals on my skin." C) "I will use a salt substitute to lower my sodium intake." D) "I will call if I develop a bothersome cough."

The answer is C. Salt substitutes contain potassium and may increase the risk of hyperkalemia with ACE inhibitors, such as fosinopril. The patient should not take potassium supplements or use salt substitutes. The other statements are appropriate for this patient.

The nurse is teaching a patient prescribed captopril [Capoten] for the treatment of hypertension. Which instructions should the nurse include? (Select all that apply.) A) Take the medication with food. B) Expect a sore throat and fever. C) Avoid potassium salt substitutes. D) A persistent dry cough may occur. E) Report difficulty in breathing immediately.

The answers are C, D, E. Salt substitutes contain potassium and may increase the risk of hyperkalemia with ACE inhibitors. A persistent, dry, nonproductive cough may develop. Angioedema includes edema of the tongue, glottis, and pharynx that may cause difficulty breathing which requires immediate medical attention. Captopril [Capoten] must be taken at least one hour before meals. A sore throat and fever are not expected adverse effects. ACE inhibitors can lower white cell count and decrease the body's ability to fight an infection. Early signs of infection include fever and sore throat.

Where is aldosterone produced?

The renal system