Angiotensin II Receptor Blockers vs. Calcium Channel Blockers

• Angiotensin II receptor blockers (ARBs) and calcium channel blockers (CCBs) are used to treat high blood pressure.
• Angiotensin II receptor blockers (ARBs) are also used to prevent diabetes and reduce the risk of stroke in patients with high blood pressure and an enlarged heart, and they may also prevent the recurrence of atrial fibrillation.
• Calcium channel blockers (CCBs) are also used to treat angina (chest pain), and abnormal heart rhythms. They also may be used after a heart attack.
• Examples of angiotensin II receptor blockers include azilsartan (Edarbi), candesartan (Atacand), eprosartan (Teveten), irbesartan (Avapro), telmisartan (Micardis), valsartan (Diovan, Prexxartan), losartan (Cozaar), olmesartan (Benicar), sacubitril/valsartan (Entresto), and nebivolol/valsartan (Byvalson).
• Examples of calcium channel blockers include amlodipine (Norvasc), amlodipine/atorvastatin (Caduet), amlodipine/benazepril (Lotrel), amlodipine/valsartan (Exforge), amlodipine/telmisartan (Twynsta), amlodipine/olmesartan (Azor), amlodipine/olmesartan/hydroclorothiazide (Tribenzor), amlodipine/aliskiren/hydroclorothiazide, amlodipine/perindopril (Prestalia), clevidipine (Cleviprex), diltiazem (Cardizem), felodipine (Cardene, Cardene SR), isradipine, nicardipine, nimodipine, nisoldipine (Sular), and verapamil (Calan).
• Side effects of angiotensin II receptor blockers (ARBs) and calcium channel blockers (CCBs) that are similar include dizziness, headache, drowsiness, rash, and low blood pressure (hypotension).
• Side effects of angiotensin II receptor blockers (ARBs) that are different from calcium channel blockers (CCBs) include cough, high blood potassium (hyperkalemia), orthostatic hypotension (low blood pressure upon standing), diarrhea, abnormal taste sensation (metallic or salty taste), fatigue, indigestion, increased blood glucose levels, flu-like symptoms, sinus infection, bronchitis, and upper respiratory tract infections.
• Side effects of calcium channel blockers (CCBs) that are different from angiotensin II receptor blockers (ARBs) include constipation, nausea, swelling of the legs and feet with fluid (edema), liver dysfunction, and over growth of the gums.

Angiotensin II receptor blockers (ARBs) are used to control high blood pressure, treat heart failure, and prevent kidney failure in people with diabetes or high blood pressure. ARBs also may prevent diabetes and reduce the risk of stroke in patients with high blood pressure and an enlarged heart, and they may also prevent the recurrence of atrial fibrillation. Angiotensin II is a potent chemical formed in the blood that causes muscles surrounding blood vessels to contract, narrowing the vessels. This narrowing increases pressure within the vessels and can cause high blood pressure (hypertension). Angiotensin II receptor blockers (ARBs) work by preventing angiotensin II from binding to angiotensin II receptors on the muscles surrounding blood vessels so blood vessels enlarge (dilate) and blood pressure is reduced.

Calcium channel blockers (CCBs) are used to treat high blood pressure, angina (chest pain), and abnormal heart rhythms. They also may be used after a heart attack. Calcium channel blockers dilate the arteries, which reduces pressure in the arteries and makes it easier for the heart to pump blood. As a result, the heart needs less oxygen, which can relieve or prevent angina. CCBs are also used to treat high blood pressure and certain types of abnormally rapid heart rhythms.

ARBs

ARBs are well tolerated by most people. 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,
• increased blood glucose levels,
• flu-like symptoms,
• sinusitis (sinus infection),
• bronchitis, and
• upper respiratory tract infections.

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

• Serious side effects of ARBs
• • The most serious, but rare, side effects are
• o kidney failure,
• o liver failure (hepatitis),
• o serious allergic reactions,
• o a decrease in white blood cells,
• o a decrease in blood platelets, and
• o 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.

CCBs

The most common side effects of calcium channel blockers are:

• Constipation
• Nausea
• Headache
• Rash
• Edema (swelling of the legs and feet with fluid)
• Low blood pressure
• Drowsiness
• Dizziness

Liver dysfunction and over growth of the gums also occurs.

When diltiazem (Cardizem) or verapamil (Calan, Isoptin) are given to individuals with heart failure, symptoms of heart failure may worsen because these drugs reduce the ability of the heart to pump blood.

Like other blood pressure medications, calcium channel blockers are associated with sexual dysfunction.

ARBs

• 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.

CCBs

Most of the interactions of calcium channel blockers occur with verapamil (Calan, Isoptin) or diltiazem (Cardizem). The interaction occurs because verapamil and diltiazem decrease the elimination of a number of drugs by the liver. Through this mechanism, verapamil and diltiazem may reduce the elimination and increase the blood levels of carbamazepine (Tegretol), simvastatin (Zocor), atorvastatin (Lipitor), and lovastatin (Mevacor). This can lead to toxicity from these drugs.

Grapefruit juice (approximately 200 ml) may elevate blood concentrations of felodipine (Plendil), verapamil (Calan, Isoptin), nisoldipine (Sular), nifedipine (Adalat, Procardia), nicardipine (Cardene), and possibly amlodipine (Norvasc). Grapefruit juice should not be consumed within 2 hours before or 4 hours after administration of affected calcium channel blockers.

ARBs

The ARBs that are currently available are:

• azilsartan (Edarbi)
• candesartan (Atacand)
• eprosartan (Teveten)
• irbesartan (Avapro)
• telmisartan (Micardis)
• valsartan (Diovan, Prexxartan)
• losartan (Cozaar)
• olmesartan (Benicar)
• entresto (sacubitril/valsartan)
• byvalson (nebivolol/valsartan)

ARBs are similar in actions and side effects. They differ in how they are eliminated from the body and the extent to which they are distributed throughout the body.

• Some ARBs need to be converted to an active form in the body before they can lower blood pressure. In addition, some ARBs are better at lowering blood pressure.
• In some studies, irbesartan (Avapro) and candesartan (Atacand) reduced blood pressure better than losartan (Cozaar).

CCBs

The calcium channel blockers that have been approved for use in the US include:

• amlodipine (Norvasc)
• amlodipine and atorvastatin (Caduet)
• amlodipine and benazepril (Lotrel)
• amlodipine and valsartan (Exforge)
• amlodipine and telmisartan (Twynsta)
• amlodipine and olmesartan (Azor)
• amlodipine and olmesartan and hydroclorothiazide (Tribenzor)
• amlodipine and aliskiren and hydroclorothiazide
• amlodipine and perindopril (Prestalia)
• clevidipine (Cleviprex)
• diltiazem (Cardizem)
• felodipine (Cardene, Cardene SR)
• isradipine
• nicardipine
• nimodipine
• nisoldipine (Sular)
• verapamil (Calan)

Calcium channel blockers differ in their duration of action, the process by which they are eliminated from the body, and, most importantly, in their ability to affect heart rate and contraction. Some calcium channel blockers (for example, amlodipine [Norvasc]) have very little effect on heart rate and contraction so they are safer to use in individuals who have heart failure or bradycardia (a slow heart rate). Verapamil (Calan, Isoptin) and diltiazem (Cardizem) have the greatest effects on the heart and reduce the strength and rate of contraction. Therefore, they are used in reducing heart rate when the heart is beating too fast.