ACE Inhibitors: Uses, Benefits, and Side Effects
Complete guide to ACE inhibitors: how they work, their benefits, side effects, and management strategies.
Understanding ACE Inhibitors
Angiotensin-converting enzyme (ACE) inhibitors are a class of medications widely prescribed to manage various cardiovascular and renal conditions. These drugs work by blocking the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor that plays a critical role in regulating blood pressure and fluid balance. By inhibiting this conversion, ACE inhibitors help relax blood vessels, decrease the amount of work the heart must perform, and ultimately reduce blood pressure. ACE inhibitors have become a cornerstone of treatment for patients with hypertension, heart failure, chronic kidney disease, and coronary artery disease.
The development of ACE inhibitors marked a significant advancement in cardiovascular medicine. These medications not only address the symptoms of various cardiovascular conditions but also provide protective effects on the heart and kidneys by reducing proteinuria and slowing disease progression. Understanding how ACE inhibitors work and their clinical applications can help patients and healthcare providers make informed decisions about treatment options.
How ACE Inhibitors Work
ACE inhibitors function by inhibiting the angiotensin-converting enzyme, which is responsible for converting angiotensin I into angiotensin II. Angiotensin II is a hormone that causes blood vessels to constrict, which increases blood pressure and forces the heart to work harder. When ACE inhibitors block this conversion, several beneficial effects occur:
- Vasodilation of the efferent arteriole: Blood vessels relax and dilate, allowing blood to flow more freely and reducing blood pressure.
- Decreased cardiac workload: The heart does not need to work as hard to pump blood throughout the body, reducing strain on the heart muscle.
- Reduced intraglomerular pressure: Lower pressure in the kidneys helps protect renal function and reduces proteinuria, making these drugs beneficial for patients with chronic kidney disease.
- Increased bradykinin levels: Inhibition of ACE, which is also a kininase enzyme, leads to accumulation of bradykinin, a substance that promotes vasodilation and reduces inflammation.
Beyond their immediate blood pressure-lowering effects, ACE inhibitors provide long-term cardiovascular and renal protection through these mechanisms.
Clinical Uses and Benefits
Hypertension Management
ACE inhibitors are among the most commonly prescribed medications for treating hypertension. They reduce blood pressure effectively and are well-tolerated by most patients. When used as monotherapy or in combination with other antihypertensive agents, ACE inhibitors help patients achieve target blood pressure goals.
Heart Failure
ACE inhibitors have been the cornerstone of treatment for patients with heart failure with reduced ejection fraction (HFrEF). Their use is associated with reduced rates of morbidity and death, improved exercise tolerance, and decreased hospitalizations. The European Society of Cardiology recommends ACE inhibitors for patients with symptomatic heart failure with reduced ejection fraction, as well as those with asymptomatic left ventricular systolic dysfunction.
Chronic Kidney Disease
ACE inhibitors reduce proteinuria by lowering intraglomerular pressure and reducing hyperfiltration, which helps slow the progression of chronic kidney disease. These medications provide renal protective effects independent of their blood pressure-lowering capabilities.
Coronary Artery Disease
For patients with stable coronary artery disease, an ACE inhibitor should be considered even with normal left ventricular function. These medications help reduce cardiovascular events and improve long-term outcomes in this patient population.
Post-Myocardial Infarction
ACE inhibitors have proven beneficial in reducing mortality and reinfarction rates in patients with a history of myocardial infarction.
Common ACE Inhibitor Medications
Several ACE inhibitors are available on the market, each with slightly different characteristics. Common examples include lisinopril and ramipril, which work by relaxing blood vessels and reducing the workload on the heart. Other commonly prescribed ACE inhibitors include enalapril, perindopril, and captopril. These medications are typically taken once or twice daily, depending on the specific agent and patient needs.
Side Effects and Adverse Reactions
Common Side Effects
While ACE inhibitors are generally well-tolerated, some patients experience side effects. The most common side effect is a persistent dry cough, which occurs in approximately 5% to 20% of patients. This cough is caused by the accumulation of bradykinin and other kinins in the lungs and typically resolves within a few weeks of discontinuing the medication.
Other common side effects may include dizziness, lightheadedness, fatigue, and headache. These effects are usually mild and may diminish with continued use.
Serious Adverse Effects
Angioedema: A potentially serious but rare side effect is angioedema, characterized by swelling of the face, lips, tongue, or throat. This condition requires immediate medical attention. African Americans have a higher risk of developing angioedema with ACE inhibitors compared with the rest of the US population, highlighting the importance of ethnic and individual considerations in medication selection.
Hyperkalemia: ACE inhibitors cause the body to retain more potassium than usual because they limit aldosterone secretion, which normally causes excess potassium to be excreted in urine. Elevated serum potassium levels can be dangerous, particularly in patients with impaired renal function or those taking other medications that raise potassium levels.
Declining Renal Function: These medications can cause a slight decrease in the glomerular filtration rate (GFR) and increase serum creatinine, particularly in patients with pre-existing renal disease or those with certain risk factors.
Ethnic Differences in Adverse Reactions
Certain populations experience higher rates of specific adverse effects. Chinese Americans have a higher risk than whites of developing cough with ACE inhibitors, while African Americans have an elevated risk of angioedema.
Monitoring and Management
Laboratory Monitoring
Patients taking ACE inhibitors require regular monitoring to ensure safety and efficacy. Healthcare providers should monitor:
- Serum potassium levels: Regular checks help identify hyperkalemia early, particularly at the start of therapy or after dose adjustments.
- Serum creatinine and GFR: These markers of kidney function should be monitored to detect any decline in renal function.
- Blood pressure: Regular blood pressure checks ensure that the medication is effectively controlling blood pressure.
Despite the benefits of ACE inhibitors, concern for adverse effects including hyperkalemia and a rise in serum creatinine has led to reluctance to prescribe these drugs, and they are often underused in patients who may derive the greatest benefit.
Managing Hyperkalemia and Renal Function
Several strategies can help manage the risk of hyperkalemia and declining renal function in patients taking ACE inhibitors. These include dietary education about limiting potassium intake, regular laboratory monitoring, dose adjustments based on kidney function, and careful consideration of concomitant medications that may increase potassium levels.
Drug Interactions
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
One of the most important drug interactions involves NSAIDs, which are commonly used for headaches, minor injuries, arthritis, and cold or flu symptoms. When taken with ACE inhibitors, NSAIDs can cause kidney failure or a condition called the “triple whammy” (TW), a life-threatening interaction that may lead to acute kidney injury. NSAIDs may also decrease the effectiveness of ACE inhibitors.
Other Significant Interactions
Other noteworthy interactions include L-arginine, which may lower blood pressure excessively when combined with ACE inhibitors, and licorice, which can counteract the effects of these medications by causing sodium retention and raising blood pressure.
Potassium-sparing diuretics, potassium supplements, and other medications that increase potassium levels should be used cautiously with ACE inhibitors due to the risk of hyperkalemia.
ACE Inhibitors versus ARBs
Comparative Efficacy
Angiotensin II receptor blockers (ARBs) were developed as an alternative for patients unable to tolerate the adverse effects of ACE inhibitors. While both drug classes inhibit the renin-angiotensin-aldosterone system, they work through different mechanisms. ACE inhibitors reduce the activity of angiotensin II at both the AT1 and AT2 receptors, while ARBs block only the AT1 receptors.
Recent evidence suggests that the presumed superiority of ACE inhibitors over ARBs may have been overstated. A meta-regression analysis showed that differences between ACE inhibitors and ARBs compared with placebo were largely due to higher event rates in placebo groups in the ACE inhibitor trials. Recent studies indicate that ARBs may produce greater decreases in cardiovascular events than ACE inhibitors, especially in patients with established cardiovascular disease.
Side Effect Profile
An important advantage of ARBs over ACE inhibitors is their superior tolerability. ARBs are generally better tolerated than ACE inhibitors, particularly regarding the incidence of cough and other side effects.
Treatment Guidelines
Despite emerging evidence of comparable efficacy, most clinical guidelines still recommend ACE inhibitors as first-line therapy for appropriate patients, with ARBs reserved for those unable to tolerate ACE inhibitors.
Combination Therapies
ACE Inhibitors with Other Cardiovascular Drugs
The addition of beta-blockers and mineralocorticoid receptor blockers to ACE inhibitors is associated with a further decrease in mortality risk for patients with HFrEF. However, some patients cannot tolerate these combinations or optimized doses because of worsening hypotension or increased risk of developing acute kidney injury or hyperkalemia.
Adding a daily low dose of a mineralocorticoid receptor blocker to an ACE inhibitor is particularly effective in controlling refractory proteinuria and is associated with decreased rates of mortality, cardiovascular mortality, and hospitalization for heart failure in patients with HFrEF. However, this regimen can lead to a higher frequency of hyperkalemia, and patients require frequent dietary education and monitoring of serum potassium.
ACE Inhibitors and Neprilysin Inhibitors
Neprilysin inhibitors represent a newer addition to heart failure therapy. The combination of the ARB valsartan and the neprilysin inhibitor sacubitril is associated with a 20% further decrease in rates of cardiovascular mortality and hospitalization and a 16% decrease in total mortality for patients with HFrEF compared with an ACE inhibitor alone. However, there can be more hypotension and angioedema with this combination. Importantly, an ACE inhibitor cannot be used together with valsartan-sacubitril due to increased risk of angioedema and cough.
Special Considerations in Surgery
ACE inhibitors require special consideration in patients undergoing noncardiac surgery. While withholding ACE inhibitors before noncardiac surgery reduces the risk of intraoperative hypotension, these medications should be restarted as soon as possible after surgery to preserve their long-term therapeutic benefits, especially in patients with cardiovascular disease.
Patient Education
Patients taking ACE inhibitors should be educated about several important aspects of their therapy:
- Take the medication as prescribed, even if feeling well
- Report persistent cough, dizziness, or difficulty breathing to their healthcare provider
- Avoid NSAIDs without consulting their healthcare provider
- Maintain regular follow-up appointments and laboratory monitoring
- Limit potassium intake in diet if advised by their healthcare provider
- Continue lifestyle modifications including diet, exercise, and stress management
- Inform all healthcare providers about ACE inhibitor use, particularly before surgery
Frequently Asked Questions
Q: How long does it take for ACE inhibitors to work?
A: ACE inhibitors typically begin lowering blood pressure within hours of the first dose, but it may take several weeks to achieve the full therapeutic effect. Patients should continue taking the medication as prescribed even if they do not feel immediate effects.
Q: Can ACE inhibitors be stopped suddenly?
A: No, ACE inhibitors should not be stopped suddenly without medical guidance. Abrupt discontinuation may lead to rebound hypertension or worsening of heart failure symptoms. Any changes to medication should be discussed with a healthcare provider.
Q: Are ACE inhibitors safe during pregnancy?
A: ACE inhibitors should be avoided during pregnancy, particularly in the second and third trimesters, as they can harm the developing fetus. Women of childbearing age should discuss contraception and pregnancy planning with their healthcare provider.
Q: Can I take ACE inhibitors with other blood pressure medications?
A: Yes, ACE inhibitors can be combined with other antihypertensive agents for better blood pressure control, but combinations should only be made under medical supervision to avoid excessive blood pressure reduction.
Q: What should I do if I experience a persistent cough?
A: A persistent dry cough is a common side effect of ACE inhibitors. If the cough is bothersome, consult your healthcare provider about switching to an ARB or other alternative medication.
References
- ACE Inhibitor and ARB Therapy: Practical Recommendations — Cleveland Clinic, Hernan Rincon-Choles, MD, MS. 2025. https://consultqd.clevelandclinic.org/ace-inhibitor-and-arb-therapy-practical-recommendations
- ACE Inhibitors and ARBs: Managing Potassium and Renal Function — Cleveland Clinic Journal of Medicine. 2019-12-15. https://www.ccjm.org/content/86/9/601
- Lisinopril Tablets — Cleveland Clinic. 2025. https://my.clevelandclinic.org/health/drugs/19162-lisinopril-tablets
- Angiotensin-Converting Enzyme Inhibitors (Drug Interactions) — EBSCO Research Starters. 2025. https://www.ebsco.com/research-starters/health-and-medicine/angiotensin-converting-enzyme-inhibitors-drug-interactions
- Hold ACE Inhibitors and ARBs Before Noncardiac Surgery — Cleveland Clinic Medical Education. October 2025. https://www.clevelandclinicmeded.com/online/journal/10_October-2025/0531681/
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