Drugs Impacting the Renin Angiotensin Aldosterone System (ACE and ARB)

module 1

Renin Angiotensin Aldosterone System (RAAS)

Helps regulate Blood Pressure through

• vasoconstriction

• ↑ blood volume

Steps of RAAS

1. blood pressure falls

2. kidneys release renin

3. renin converts angiotensinogen into angiotensin I

4. angiotensin converting enzyme (ACE) converts angiotensin I to angiotensin II

5. angiotensin II causes muscles of small arteries to constrict

   1. increases BP

6. angiotensin II also releases aldosterone, from adrenal cortex, and vasopressin (antidiuretic hormone), from the pituitary gland

   1. prompts the kidneys to retain sodium and secrete potassium

      1. causes water to be retained, increasing BP

Medications that Impact RAAS

• ACE inhibitors

• Angiotensin II receptor blockers (ARBs)

Both used to treat hypertension and heart failure

ACE Inhibitors

Typically used to treat hypertension and heart failure, as well as used for patients who have had MI

• usually end in “-PRIL”

  • enalapril, lisinopril, ramipril, benazepril, and captopril

  • taken orally

    • except for enalaprilat, which can be taken intravenously for hypertension if oral route is not available

Angiotensin II receptor blockers (ARBs)

Typically used to treat hypertension and heart failure

• usually end in “-SARTAN”

  • candesartan, valsartan, irbesartan, losartan

  • taken orally

How do ACE Inhibitors lower BP

prevent the conversion of angiotensin I to angiotensin II

How do ARBs Inhibitors lower BP

block the actions of angiotensin II

Side effects of ACE inhibitors and ARBs

mild & nonspecific

• headaches

• dizziness

• fatigue

others:

• tachycardia

• hypotension

  • both tend to occur with the first few doses

• hyperkalemia

  • decrease K excretion in the urine, so pt taking these should avoid taking K supplements

Side effects of ACE inhibitors

• persistent, dry, irritating cough

• potential fluid accumulation & swelling of the eyes, lips, tongue, pharynx, and glottis due to increased capillary permeability

  • called Angioedema and can be life threatening

Contraindications of ACE Inhibitors & ARBs

Avoid in patients who:

• take potassium-sparing diuretics

• have another underlying cause of hyperkalemia

Give in caution for patients with renal stenosis

Black Box Warning for ACE Inhibitors & ARBs

cause fetal injury or death, so they should not be used during pregnancy

Nursing Considerations & Pt Education

1. perform baseline assessment and take vital signs

2. review diagnostic tests like:

• CBC, sodium, potassium, creatinine, BUN, and urinalysis, negative pregnancy test

3. ensure your patient understands why the medication has been prescribed

4. emphasize taking meds exactly as directed and to not discontinue abruptly

5. avoid K+ supplements & salt substitutes that contain K+

6. avoid taking NSAIDs and teach them about lifestyle modifications they can do

7. periodically monitor BP & Labs

8. Evaluate for therapeutic effect of medication (↓BP or symptoms of heart failure)