Angiotensin II Receptor Blockers

Conditions treated

Angiotensin-II receptor blockers (ARBs) are prescribed for a variety of conditions, including:

Conditions of concern

Certain conditions increase the risk of side effects or other potential problems for patients taking angiotensin-II receptor blockers (ARBs). These include:

• Previous allergic reaction to ARBs or similar medications (e.g., ACE inhibitors).
• Valvular stenosis (particularly in the aortic or mitral valves). A condition in which there is a narrowing, stiffening, thickening or blockage of one or more heart valves.
• Angioedema. A type of edema (swelling) in the head, neck, face, ankles or legs that can lead to difficulty breathing or swallowing.
• Kidney or liver disease. Blood pressure-lowering effects of ARBs may be increased in patients with these conditions.
• Pregnancy. ARB use may cause birth defects.
• Dehydration. Blood pressure-lowering effects of ARBs may be increased in dehydrated patients.

Potential side effects

Though the potential for side effects exists with all medications, angiotenisn-II receptor blockers (ARBs) have few common side effects. In fact, one benefit of angiotensin-II receptor blockers is that they generally do not cause the most common side effect associated with angiotensin converting enzyme (ACE inhibitors – a dry, persistent cough.

One potentially serious side effect is hyperkalemia – an abnormally high level of potassium in the blood. However, patients taking ARBs usually have regular blood tests to check potassium levels and therefore avoid any serious consequences. Other serious side effects may occur with ARBs, but are rare. People should seek medical attention immediately for any side effects of hyperkalemia or an allergic or other severe reaction to angiotensin-II receptor blockers, including:

• Fainting (syncope)
• Dizziness or lightheadedness
• Difficulty swallowing or breathing
• Shortness of breath
• Edema (swelling), especially in the head, face or neck
• Abdominal pain or vomiting
• Persistent nausea or diarrhea
• Skin rash, with or without itching
• Chest pain or palpitations
• Unusual cough or congestion
• Persistent headache
• Flu-like symptoms (with or without fever)
• Joint or muscle pain or weakness

Other potential side effects of ARBs include

• Headache
• Nausea or upset stomach
• Drowsiness, weakness or fatigue
• Runny nose or sinus pain
• Sore throat or cough
• Depression or anxiety
• Back pain
• Salty or metallic taste in mouth

Drug or other interactions

Patients should consult their physician before taking any other medication (either prescription or over-the-counter), herbal remedies or nutritional supplements. Of particular danger to individuals taking A-II receptor blockers (ARBs) are:

• Potassium supplements. Use increases the risk of hyperkalemia (too much potassium in the body).
• Salt substitutes or other low-salt products that use potassium chloride. Use increases the risk of hyperkalemia.
• Diuretics (some types).
• Nonsteroidal anti-inflammatory drugs (NSAIDs).
• Insulin and antidiabetic medications. Use of certain ARBs may increase the effect of these medications on insulin levels in the body.
• Some antidepressants (e.g., lithium). Use of certain ARBs can prevent these medications from being removed from the body by the kidneys. Therefore, the risk of side effects or overdose may be greater in patients taking ARBs.
• Some antibiotics (e.g., trimethoprim, rifampicin, fluconazole).
• Barbiturates. Use of ARBs may increase the depressant effects of these medications.
• Over-the-counter (OTC) medications that increase blood pressure. These include (but are not limited to) diet pills and medications used to treat asthma, flu, colds, cough, sinus problems or hay fever.
• Grapefruit juice.
• Alcohol.

Lifestyle considerations

Angiotensin-II receptor blockers (ARBs) are only one part of a treatment plan for high blood pressure, heart failure or other conditions. That plan usually includes a number of lifestyle changes including weight loss, eating a heart-healthy diet, regular exercise and more. ARBs reduce the symptoms, but do not cure the underlying condition. Therefore, many patients taking ARBs will be on the medication for the rest of their lives, provided no serious side effects occur.

Often, the symptoms that led the patients to seek medical attention will stop once ARBs are introduced. Patients should still continue to take their medication exactly as directed and to keep all scheduled follow-up appointments with their physician.

When first taking ARBs, patients may be advised to avoid driving or operating heavy machinery until they know how the medication will affect them. Patients are more likely to have side effects from ARBs or other antihypertensives if they spend too much time in the heat. Therefore, patients should be certain to drink enough liquids during exercise or in hot weather. Patients may also be directed to take their own blood pressure readings regularly, reporting anything unusual to their physicians.

Patients taking ARBs should inform their physician if they become ill from any cause, especially if severe diarrhea or vomiting occurs. These conditions can cause the body to lose too much water and potassium, leading to low blood pressure (hypotension).

Patients should not stop taking ARBs abruptly unless advised by their physician. Doing so might lead to medical complications.

Pregnant patients should not take ARBs, and women who are or are planning to become pregnant should tell their physicians before taking ARBs.

Pregnancy use issues

Women are advised against taking Angiotensin–II receptor blockers (ARBs) during pregnancy, especially during the second and third trimesters. Patients taking ARBs should inform their physician immediately if they become pregnant or are planning to become pregnant, so they can start alternative therapy.

When breastfeeding, some ARBs will pass into breast milk, and the effects of this on the nursing infant are unknown. Therefore, an alternative feeding method is recommended when mothers are taking ARBs.

Child use issues

Use of certain most angiotensin-II receptor blockers (ARBs) may not be recommended in children of any age, but especially under 6 years old. Also, because children are more sensitive to the effects of ARBs on blood pressure, they are at higher risk of side effects. Parents are encouraged to discuss the potential risks and benefits with a pediatric cardiologist before their child begins taking ARBs.

Elderly use issues

Certain types of angiotensin-II receptor blockers (ARBs) may not be recommended for use in older adults. In general, older adults may be more sensitive to the effects of medications and therefore at higher risk of side effects. Dosages tend to begin on the lower end of acceptable ranges for this population. In addition, elderly patients are more likely to have impaired renal kidney function, which can increase the risk of hyperkalemia (too much potassium in the blood). Therefore, elderly patients may undergo blood or other testing to determine kidney function before being prescribed ARBs.