• Beta blockers and ARBs are used to treat high blood pressure and heart failure.
• Examples of beta blockers include acebutolol (Sectral), atenolol (Tenormin), betaxolol (Kerlone, Betoptic S), bisoprolol fumarate (Zebeta), carvedilol (Coreg), esmolol (Brevibloc), metoprolol (Lopressor, Toprol XL), nadolol (Corgard), nebivolol (Bystolic), penbutolol (Levatol), propranolol (Hemangeol, Inderal LA, Inderal XL, InnoPran XL), sotalol (Betapace, Sorine), and timolol ophthalmic (Timoptic, Betimol, Istalol).
• Examples of ARBs include azilsartan (Edarbi), candesartan (Atacand), eprosartan (Teveten), irbesartan (Avapro), telmisartan (Micardis), valsartan (Diovan), losartan (Cozaar), and olmesartan (Benicar).
• Side effects of beta blockers and ARBs that are similar include rash, diarrhea, and fatigue.
• Side effects of beta blockers that are different from ARBs include nausea, stomach cramps, vomiting, blurred vision, disorientation, insomnia, hair loss, weakness, muscle cramps, and sexual dysfunction.
• Side effects of ARBs that are different from beta blockers include cough, high blood potassium (hyperkalemia), low blood pressure, dizziness, headache, drowsiness, metallic or salty taste in the mouth, orthostatic hypotension (low blood pressure upon standing), indigestion, and upper respiratory tract infection.
• Sudden withdrawal from beta blockers may worsen angina (chest pain) and cause heart attacks, serious abnormal heart rhythms, or sudden death.

Beta blockers, or beta-adrenergic blocking agents, block the neurotransmitters norepinephrine and epinephrine (adrenaline) from binding to beta-receptors on nerves. This helps dilate blood vessels, which results in a reduction of heart rate and blood pressure. Beta blockers are used to treat high blood pressure, angina (chest pain), heart failure, abnormal heart rhythms, tremors, pheochromocytoma, migraine headache prevention, hypertrophic subaortic stenosis, hyperthyroidism, panic disorder, anxiety, akathisia (restlessness or inability to sit still), eye pressure caused by glaucoma, and aggressive behavior. Beta blockers are also used to prevent future heart attacks and death after a heart attack.

Angiotensin II receptor blockers (ARBs) block the action of angiotensin II by preventing it from binding to receptors on the muscles surrounding blood vessels. Angiotensin II causes muscles surrounding blood vessels to contract, which increases pressure within the vessels and can cause high blood pressure (hypertension). When angiotensin II can’t bind to receptors, blood vessels enlarge (dilate) and blood pressure is reduced, making it easier for the heart to pump blood. ARBs are used to treat high blood pressure and heart failure, and to prevent kidney failure in people with diabetes or high blood pressure. ARBs are also used in patients with high blood pressure and an enlarged heart to prevent diabetes and reduce the risk of stroke. ARBs also may prevent atrial fibrillation from recurring.

Beta Blockers

Beta blockers may cause:

• Diarrhea
• Stomach cramps
• Nausea
• Vomiting

Other important side effects include:

• Rash
• Blurred vision
• Disorientation
• Insomnia
• Hair loss
• Weakness
• Muscle cramps
• Fatigue

As an extension of their beneficial effect, they slow heart rate and reduce blood pressure, but they may cause adverse effects such as heart failure or heart block in patients with heart problems.

Beta blockers should not be withdrawn suddenly because sudden withdrawal may worsen angina (chest pain) and cause heart attacks, serious abnormal heart rhythms, or sudden death.

Central nervous system effects of beta blockers include:

• Headache
• Depression
• Confusion
• Dizziness
• Nightmares
• Hallucinations

Beta blockers that block β2 receptors may cause shortness of breath in asthmatics.

As with other drugs used for treating high blood pressure, sexual dysfunction may occur.

Beta blockers may cause low or high blood glucose and mask the symptoms of low blood glucose (hypoglycemia) in people with diabetes.
Other serious side effects of beta-blockers include:

• Raynaud's phenomenon
• Lupus erythematosus
• Bronchospasm
• Serious allergic reactions
• Erythema multiform
• Steven Johnson Syndrome
• Toxic epidermal necrolysis

ARBs

ARBs are well tolerated by most individuals. The most common side effects are

• cough,
• elevated potassium levels in the blood (hyperkalemia),
• low blood pressure,
• dizziness,
• headache,
• drowsiness,
• diarrhea,
• abnormal taste sensation (metallic or salty taste),
• rash,
• orthostatic hypotension (low blood pressure upon standing),
• fatigue,
• indigestion, and
• upper respiratory tract infection.

Compared to ACE inhibitors, cough occurs less often with ARBs.

The most serious, but rare, side effects are

• kidney failure,
• liver failure (hepatitis),
• serious allergic reactions,
• a decrease in white blood cells,
• a decrease in blood platelets, and
• swelling of tissues (angioedema).

There have been reports of rhabdomyolysis (destruction of skeletal muscle) in patients receiving ARBs.

Individuals who have narrowing of both arteries that supply the kidneys or have had a severe reaction to ARBs should avoid them.

Like other antihypertensives, ARBs have been associated with sexual dysfunction.

Beta Blockers

ARBs

• Combining propranolol (Inderal) or pindolol (Visken) with thioridazine (Mellaril) or chlorpromazine (Thorazine) may result in low blood pressure (hypotension) and abnormal heart rhythms because the drugs interfere with each other's elimination and result in increased levels of the drugs.
• Dangerous elevations in blood pressure may occur when clonidine (Catapres) is combined with a beta blocker, or when clonidine or beta blocker is discontinued after their concurrent use. Blood pressure should be closely monitored after initiation or discontinuation of clonidine or a beta blocker when they have been used together.
• Phenobarbital and similar agents may increase the breakdown and reduce blood levels of propanolol (Inderal) or metoprolol (Lopressor, Toprol XL). This may reduce effectiveness of the beta blocker.
• Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) (for example, ibuprofen) may counteract the blood pressure reducing effects of beta blockers by reducing the effects of prostaglandins, which play a role in control of blood pressure.
• Beta blockers may prolong hypoglycemia (low blood sugar) and mask symptoms of hypoglycemia in diabetics who are taking insulin or other diabetic medications.
• ARBs have few interactions with other drugs.
• Since ARBs may increase blood levels of potassium, the use of potassium supplements, salt substitutes (which often contain potassium), or other drugs that increase potassium may result in excessive blood potassium levels and cardiac arrhythmias.
• ARBs may also increase the blood concentration of lithium (Eskalith, Lithobid) and lead to an increase in side effects from lithium.
• Rifampin (Rifadin) reduces the blood levels of losartan, and fluconazole (Diflucan) reduces the conversion of losartan to its active form. These effects could decrease the effects of losartan.
• ARBs should not be combined with ACE inhibitors because such combinations increase the risk of hypotension, hyperkalemia, and renal impairment.
• ARBs should not be combined with aliskiren (Tekturna) because such combinations increase the risk of kidney failure, excessive low blood pressure, and hyperkalemia.

Beta Blockers

• acebutolol (Sectral)
• atenolol (Tenormin)
• betaxolol (Kerlone)
• betaxolol (Betoptic S)
• bisoprolol fumarate (Zebeta)
• carteolol (Cartrol, discontinued)
• carvedilol (Coreg)
• esmolol (Brevibloc)
• labetalol (Trandate [Normodyne - discontinued])
• metoprolol (Lopressor, Toprol XL)
• nadolol (Corgard)
• nebivolol (Bystolic)
• penbutolol (Levatol)
• pindolol (Visken, discontinued)
• propranolol (Hemangeol, Inderal LA, Inderal XL, InnoPran XL)
• sotalol (Betapace, Sorine)
• timolol (Blocadren, discontinued)
• timolol ophthalmic solution (Timoptic, Betimol, Istalol)

ARBs

The following is a list of currently available ARBs:

• azilsartan (Edarbi)
• candesartan (Atacand),
• eprosartan (Teveten),
• irbesartan (Avapro),
• telmisartan (Micardis),
• valsartan (Diovan),
• losartan (Cozaar), and
• olmesartan (Benicar).