ANGIOTENSIN II–RECEPTOR BLOCKERS(ARBs)

1. ANGIOTENSIN II–RECEPTOR BLOCKERS(ARBs)

2. ANGIOTENSIN II–RECEPTOR BLOCKERS(ARBs) • The ARBs include the following drugs: • azilsartan (Edarbi),candesartan (Atacand), eprosartan (Teveten), irbesartan(Avapro), losartan (Cozaar), olmesartan (Benicar), telmisartan(Micardis), and valsartan (Diovan).

3. Therapeutic Actions and Indications • The ARBs selectively bind with the angiotensin II receptors in vascular smooth muscle and in the adrenal cortex to block vasoconstriction and the release of aldosterone. • These actions block the blood pressure–raising effects of the renin–angiotensin system and lower blood pressure.

4. Pharmacokinetics - These agents are all given orally. They are well absorbed and undergo metabolism in the liver by the cytochrome P450 system. - They are excreted in feces and in urine. • The ARBs cross the placenta. • It is not known whether they enter breast milk during lactation.

5. Contraindications and Cautions - The ARBs are contraindicated in the presence of allergy. - Caution should be used in the presence of hepatic or renal dysfunction - with hypovolemia,because of the blocking of potentially life-saving compensatory mechanisms. - These drugs are also contraindicated during pregnancy. Although it is not known whether the ARBs enter breast milk during lactation,these drugs should not be used during lactation because of the potential for serious adverse effects in the neonate.

6. Adverse Effects - headache, dizziness, syncope,and weakness, which could be associated with drops in blood pressure; hypotension; GI complaints,including diarrhea, abdominal pain, nausea, dry mouth,and tooth pain; symptoms of upper respiratory tract infections and cough; and rash, dry skin, and alopecia.

7. Clinically Important Drug–Drug Interactions The risk of decreased serum levels and loss of effectiveness increases if the ARB is taken in combination with phenobarbital, indomethacin, or rifamycin. If this combination is used, the patient should be monitored closely and dose adjustments made. There may be a decrease in anticipated antihypertensive effects if the drug is combined with ketoconazole, fl uconazole, or diltiazem. Monitor the patient closely and adjust dose as needed.

8. Implementation With Rationale - Encourage patient to implement lifestyle changes, including weight loss, smoking cessation, decreased alcohol and salt in the diet, and increased exercise, to increase the effectiveness of antihypertensive therapy. - Administer without regard to meals; give with food to decrease GI distress if needed. - if the patient is to undergo surgery to notify medical personnel that the blockage of compensatory angiotensin II could result in hypotension after surgery that would need to be reversed with volume expansion.

9. …Implementation With Rationale - Find an alternative method of feeding the baby if the patient is nursing to prevent the potentially dangerous blockade of the renin–angiotensin–aldosterone system in the neonate. - Monitor the patient carefully in any situation that might lead to a drop in fluid volume (e.g., excessive sweating, vomiting, diarrhea, dehydration) to detect and treat excessive hypotension that may occur.

10. …Implementation With Rationale • Provide comfort measures to help the patient tolerate drug effects, including small, frequent meals; access to bathroom facilities; safety precautions if central nervous system effects occur; environmental controls; appropriate skin care as needed; and analgesics as needed.