ACE Inhibitors

The class of drugs calledangiotensin converting enzyme(ACE) inhibitors, as the class name suggests, reduces the activity ofangiotensinconvertingenzyme．ACE converts angiotensin I produced by the body to angiotensin IIintheblood．血管紧张素ⅱ我s a very potent chemical that causes the muscles surrounding blood vessels to contract and narrow the blood vessels. Narrowing of blood vessels increases the pressure within the blood vessels and may lead tohigh blood pressure(hypertension).

By reducing the activity of ACE,ACE inhibitorsdecrease the formation of angiotensin II which leads to widening (dilation) of blood vessels, and thereby reducesblood pressure．By lowering blood pressure against which theheartmust pump, the amount of work that the heart must do is reduced. ACE inhibitors also reduce blood pressure in the kidneys, slowing the progression ofkidneydiseasedue to high blood pressure ordiabetes．

ACE inhibitors are effective for

• controlof blood pressure,
• congestive heart failure, and
• prevention ofstrokeand hypertension, or diabetes-related kidney damage.

ACE inhibitors are especially important because they have been shown to prevent

• earlydeathresulting from hypertension,
• heart failure, or heart attacks; in studies of patients with hypertension, heart failure, or prior heart attacks, patients who received an ACE inhibitor survived longer than patients who did not receive an ACE inhibitor.
• ACE inhibitors may be combined with other drugs to achieve optimal blood pressure control.

• ACE inhibitors are very similar, and all are effective for treating hypertension.
• Some are eliminated primarily by the kidneys while others are also eliminated inbileandfeces．
• This difference in elimination may be important in choosing among ACE inhibitors in patients with reduced kidney orliverfunction, who may accumulate drugs that are excreted via the kidneys or liver.
• Except forcaptopril(Capoten) andlisinopril(Prinivil,Zestril), ACE inhibitors are inactive until they are converted to an active form in the body.

Common side effects are:

• dizziness,
• headache,
• drowsiness,
• diarrhea,
• low blood pressure,
• weakness,
• cough, and
• rash．

Rare side effects of ACE inhibitors include

• Anabnormaltaste(metallic or salty), elevated bloodpotassiumlevels, and sexualdysfunctionmay also occur.
• A nonproductive and persistent cough may occur in 5%-25% of individuals. It may take up to 2 weeks or longer for coughing to subside after the ACE inhibitor is discontinued. If one ACE inhibitor causes cough, it is likely that the others will also.
• 血管紧张素转换酶抑制剂可能导致出生缺陷,therefore, should not be used duringpregnancy．
• Individuals withstenosis(narrowing) of both arteries supplying the kidneys may experience worsening of kidney function.

Other side effects of ACE inhibitors include

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

ACE inhibitors have few important interactions with other drugs.

• Quinapril(Accupril) may reduce theabsorptionoftetracyclinebecause quinapril (Accupril) containsmagnesiumwhich binds to tetracycline in theintestineand prevents its absorption.
  
  
• Combining potassium supplements, salt substitutes (which often contain potassium), or other drugs that increase potassium levels with ACE inhibitors may result in excessive blood potassium levels because ACE inhibitors can further increase potassium to toxic levels.
  
  
• ACE inhibitors may increase blood concentrations of lithium (Eskalith) and possibly increase side effects of lithium.
  
  
• Nonsteroidal antiinflammatory drugs [NSAIDs, for example, aspirin, ibuprofen, indomethacin (Indocin, Indocin IV), and naproxen (Naprosyn, Naprelan)] may reduce the blood pressure-lowering effects of ACE inhibitors.

The following is a list of the ACE inhibitors that are available in the United States:

• benazepril(Lotensin, LotensinHct),
• captopril (Capoten),
• enalapril(Vasotec),
• fosinopril (Monopril),
• lisinopril (Prinivil, Zestril),
• moexipril (Univasc)
• perindopril (Aceon),
• quinapril (Accupril),
• ramipril(Altace), and
• trandolapril (Mavik).