ARBs (Angiotensin II Receptor Blockers)

What This Medicine Does

ARBs (Angiotensin II Receptor Blockers) are blood pressure medicines that work by blocking a hormone called angiotensin II. This hormone normally tightens your blood vessels and raises your blood pressure. By blocking it, ARBs relax your blood vessels, allowing blood to flow more easily and lowering your blood pressure.

Why doctors choose ARBs:

• They work as well as ACE inhibitors but cause less cough
• They specifically protect the kidneys in people with diabetes
• Telmisartan may help improve insulin sensitivity
• Generally well-tolerated with few side effects

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Common Things You Might Notice

Most people take ARBs without problems. The most common side effects are mild and often go away as your body adjusts:

• Dizziness - Especially when standing up quickly. Take your time getting up from sitting or lying down.
• Tiredness - You may feel more tired than usual, especially when starting the medicine.
• Mild stomach upset - Taking with food can help if this occurs.

Good news: ARBs cause much less dry cough than similar medicines (ACE inhibitors).

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When to Call Your Doctor

Seek Immediate Care For:

• Swelling of your face, lips, tongue, or throat
• Difficulty breathing or swallowing
• Severe dizziness or fainting

Contact Your Doctor Soon For:

• Muscle weakness or irregular heartbeat (may indicate high potassium)
• Nausea, vomiting, or diarrhea that doesn't stop
• Unusual changes in urination
• Signs of kidney problems (foamy urine, swelling in hands/feet)

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Practical Daily Tips

1. Take it at the same time each day - This helps maintain steady blood levels. Many people take it in the morning with breakfast.

2. Rise slowly - When getting up from sitting or lying down, do it slowly to avoid dizziness.

3. Check your blood pressure - Keep a log at home to track how well the medicine is working.

4. Don't stop suddenly - Stopping abruptly can cause your blood pressure to spike. Always talk to your doctor first.

5. Tell other doctors - Always mention you're taking an ARB when getting new prescriptions.

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For Healthcare Professionals

Clinical Information

Pharmacology & Mechanism

ARBs selectively block the angiotensin II type 1 (AT1) receptor, preventing vasoconstriction, aldosterone secretion, sympathetic activation, and antidiuretic hormone release. Unlike ACE inhibitors, ARBs do not affect bradykinin metabolism, resulting in lower cough incidence.

Dosing & Titration

• Split dosing: Consider BID dosing for BP variability or inadequate morning control
• Telmisartan: Longest half-life (~24 hours); may be preferred for BP variability control

Monitoring Requirements

Baseline:

• Potassium, creatinine, eGFR
• Blood pressure measurement

Follow-up (1-2 weeks after start/dose change):

• Potassium, creatinine, eGFR
• Blood pressure

Ongoing (every 3-6 months):

• Potassium, creatinine, eGFR
• Blood pressure
• Urine albumin-to-creatinine ratio (if diabetic)

Expected Lab Changes:

• Creatinine: Small increase (≤30%) is acceptable and expected
• Potassium: Monitor for hyperkalemia, especially in CKD or with RAAS blockers

Contraindications & Warnings

Absolute Contraindications:

• Pregnancy (Category D)
• History of angioedema
• Bilateral renal artery stenosis

Use with Caution:

• Renal artery stenosis (unilateral)
• Severe renal impairment (eGFR ＜30)
• Hyperkalemia risk (CKD, diabetes, elderly)
• Volume depletion (diuretics, dehydration)

Drug Interactions

Special Populations

Pregnancy: Category D - discontinue immediately; consider alternative antihypertensives

Breastfeeding: Limited data; consider alternative agents

Renal Impairment: Dose adjustment may be needed; monitor potassium and creatinine closely

Geriatric: Start at lower end of dosing range; increased fall risk from hypotension

Efficacy Data

ARBs reduce major cardiovascular events by approximately 10-15% compared to placebo in high-risk patients. In diabetic nephropathy, ARBs reduce progression to macroalbuminuria by ~40% compared to placebo.

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Medical Disclaimer: This content is for educational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider before starting, stopping, or changing any medication.

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References

1. FDA ARB Prescribing Information (losartan, valsartan, olmesartan, telmisartan). U.S. Food and Drug Administration. https://www.accessdata.fda.gov/scripts/cder/daf/
2. Whelton PK, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. Journal of the American College of Cardiology. 2018;71:e127-e248. https://www.acc.org/guidelines
3. ESC Guidelines for arterial hypertension. European Heart Journal. 2018;39:3021-3104. https://www.escardio.org/Guidelines
4. ARBs in Diabetic Kidney Disease. Kidney International. 2020;98:567-578. https://www.nih.gov/
5. American Heart Association. ARBs and Hypertension Management. https://www.heart.org/