Angiotensin II Receptor Blockers (ARBs)

Introduction

• ARBs are known as angiotensin II receptor blockers or antagonists.
• The suffix for ARBs is "-sartan."

Mechanism of Action

• ARBs block the binding of angiotensin II to its receptors.
• Angiotensinogen is converted to angiotensin I by renin, and then to angiotensin II by the angiotensin-converting enzyme.
• Angiotensin II is a potent vasoconstrictor.
• Unlike ACE inhibitors, ARBs do not inhibit the conversion of angiotensin I to angiotensin II but block angiotensin II from binding to its receptor.
• This blocking prevents vasoconstriction, reducing blood pressure.

Therapeutic Effects

• Decreases blood pressure, systemic vascular resistance, and afterload.
• Provides renal vascular protective effects similar to ACE inhibitors.

Indications

• Used for hypertension, especially in patients intolerant to ACE inhibitors (e.g., due to angioedema).
• Major use in afterload reduction for conditions like congestive heart failure (CHF) and myocardial infarction (MI).
• Given to diabetic patients for renal protective properties.

Precautions

• Concurrent use of multiple drugs affecting blood pressure can lead to severe hypotension.
• Impaired renal function may affect drug excretion.

Contraindications

• Affects potassium levels; monitor for hyperkalemia.
• Contraindicated in pregnant or lactating women and pediatric patients under a year old due to kidney development concerns.

Side and Adverse Effects

• Common side effects include angioedema, cough, fatigue, dizziness, and hyperkalemia.
• Differentiating side effects from ACE inhibitors include headaches and upper respiratory infections.

Nursing Actions

• Assess and monitor blood pressure, input and output, daily weights, and presence of side effects.
• Perform physical assessments focusing on cardiac and pulmonary health.
• Lab work should include monitoring renal function and potassium levels.

Patient Education

• Educate on drug use, side effects, and how to monitor blood pressure at home.
• Discuss potential interactions with other drugs and symptoms of hypo- and hypertension.

Medications

• Examples: Omnisartan and Losartan, with "-sartan" indicating an ARB.