What is the fastest acting Angiotensin-Converting Enzyme (ACE) inhibitor?

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Last updated: May 3, 2025View editorial policy

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From the FDA Drug Label

In most patients studied, onset of antihypertensive activity was seen at one hour after oral administration of an individual dose of lisinopril, with peak reduction of blood pressure achieved by 6 hours

The most faster acting ACE inhibitor is Lisinopril, with an onset of action of 1 hour and peak reduction of blood pressure achieved by 6 hours 1.

  • Key points:
    • Onset of action: 1 hour
    • Peak reduction of blood pressure: 6 hours
  • Main idea: Lisinopril has a relatively fast onset of action compared to other ACE inhibitors.

From the Research

The fastest-acting ACE inhibitor is captopril, which begins working within 15-30 minutes after oral administration. Captopril is typically dosed at 12.5-25 mg orally, with effects peaking around 1-2 hours after intake. This rapid onset makes captopril particularly useful in hypertensive urgencies where quick blood pressure reduction is needed. The medication works by blocking the conversion of angiotensin I to angiotensin II, thereby reducing vasoconstriction and blood pressure. Unlike other ACE inhibitors that require hepatic activation, captopril is active in its administered form, explaining its faster onset. When using captopril, monitor for common side effects including hypotension, cough, hyperkalemia, and angioedema. The medication can be taken with or without food, though food may slightly delay absorption. For maintenance therapy, longer-acting ACE inhibitors like lisinopril or enalapril are often preferred due to their once-daily dosing convenience.

Some key points to consider when using captopril include:

  • Its rapid onset of action, making it suitable for hypertensive emergencies 2
  • The importance of monitoring for side effects, such as hypotension and hyperkalemia 3
  • The potential for captopril to be used in combination with other medications, such as diuretics and beta-blockers 4
  • The availability of alternative ACE inhibitors, such as lisinopril and enalapril, which may be preferred for maintenance therapy due to their longer duration of action 5, 6

Overall, captopril is a valuable option for the treatment of hypertension and heart failure, particularly in situations where rapid blood pressure reduction is necessary. Its efficacy and safety profile make it a commonly used medication in clinical practice 2.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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