VentralinkVentralink Medication Education Series
ACE Inhibitors & ARBs • Article 6 of 6
ACE Inhibitors vs. ARBs
What's the Difference and Which Is Right for You?
A head-to-head comparison of lisinopril, losartan, and their medication families
Key Takeaways
- Same effectiveness: ACE inhibitors and ARBs work equally well for blood pressure, heart failure, and kidney protection
- Different side effects: ACE inhibitors cause cough in 5-20% of patients; ARBs rarely do
- Either can be first choice: Many doctors now start directly with ARBs due to better tolerability; both are valid first-line options
- Shared cautions: Both classes require monitoring of kidney function and potassium levels
If you've read through our series on ACE inhibitors and ARBs, you've seen the impressive benefits: extending life in heart failure, protecting hearts after heart attacks, preventing strokes and heart attacks in high-risk patients, and slowing diabetic kidney disease. But you may have noticed something: both drug classes seem to work for all these conditions.
So what's the difference? When should your doctor choose one over the other? And if you're already on one of these medications, should you consider switching?
Two Paths to the Same Destination
As we discussed in Article 1, the renin-angiotensin system is like a cascade—one hormone triggers the next, ultimately producing angiotensin II, which raises blood pressure and causes other harmful effects. ACE inhibitors and ARBs both block this system, but at different points.
Think of it this way: ACE inhibitors prevent the creation of a harmful chemical messenger. ARBs let the messenger be created but block it from delivering its message. Either way, the harmful effects of angiotensin II are prevented.
The Cough: The Most Important Practical Difference
This is a tickly, non-productive cough that doesn't go away. It's not dangerous, but it can be very annoying—some patients describe it as a constant urge to clear their throat. It's caused by bradykinin, a substance that builds up when ACE is blocked. ARBs don't affect bradykinin, so they rarely cause cough.
Important Note About the Cough
The cough from ACE inhibitors can take weeks or even months to develop. If you've been on an ACE inhibitor for a while and develop a persistent cough, mention it to your doctor. Switching to an ARB usually resolves it within a few weeks.
Angioedema: A Rare But Serious Concern
Sudden swelling of the face, lips, tongue, or throat. This is rare but can be life-threatening if it affects the airway. It's also caused by bradykinin buildup. If you've had angioedema with an ACE inhibitor, you should NOT take another ACE inhibitor, and most doctors will be cautious about ARBs as well (though they're generally safer).
⚠️ Warning: Higher Risk Groups
Angioedema is 2-4 times more common in Black patients. This is one reason ARBs may be preferred as first-line therapy in this population, though both classes are still effective and widely used.
Side Effects Both Classes Share
Because ACE inhibitors and ARBs work on the same hormone system, they share some effects that require monitoring:
High Potassium
Both can raise potassium levels. Your doctor will check blood tests periodically, especially if you have kidney disease or take other medications that affect potassium.
Kidney Function Changes
A small rise in creatinine (a measure of kidney function) is normal when starting these medications. Larger increases need attention.
Low Blood Pressure
Especially with the first dose or if you're dehydrated. Dizziness when standing up can occur.
Pregnancy Risk
Both classes can cause serious harm to developing babies. Women who could become pregnant should discuss alternatives.
When Doctors Choose One Over the Other
Quick Decision Guide
Summary: Making the Choice
Effectiveness: Both classes work equally well for blood pressure, heart protection, and kidney protection
Main difference: ACE inhibitors cause cough in 5-20% of patients; ARBs rarely do
Switching is easy: If one class causes problems, the other usually works without issues
Don't combine: Taking both an ACE inhibitor and ARB together doesn't help and increases side effects
What matters most: Taking one of these medications consistently. The choice between them is far less important than taking either one.
Questions to Ask Your Doctor
- • "Am I on an ACE inhibitor or an ARB? Why was that one chosen for me?"
- • "If I'm having side effects, could I switch to the other type?"
- • "How often do I need blood tests to monitor my kidney function and potassium?"
- • "Are there any medications or supplements I should avoid while taking this?"