Can perindopril (angiotensin-converting enzyme inhibitor) cause diarrhea?

Can Perindopril Cause Diarrhea?

Yes, perindopril can cause diarrhea, though it occurs infrequently as a direct adverse effect (reported in approximately 4-5% of patients), and more rarely as part of serious gastrointestinal angioedema.

Direct Gastrointestinal Side Effects

According to the FDA drug label, diarrhea is a recognized adverse effect of perindopril, occurring in 4.3% of patients in U.S. placebo-controlled trials 1. This represents a relatively uncommon but documented side effect that typically does not require drug discontinuation. In a Chinese study, diarrhea occurred in 5% of patients treated with perindopril 2.

The mechanism appears related to ACE inhibitor effects on bradykinin metabolism and prostaglandin release, which can affect gastrointestinal motility and secretion.

Serious Gastrointestinal Manifestations

More concerning is ACE inhibitor-induced gastrointestinal angioedema, a rare but potentially serious complication that presents with abdominal pain, nausea, vomiting, and diarrhea 3, 4, 5. While most case reports involve other ACE inhibitors like lisinopril, this is considered a class effect affecting all ACE inhibitors including perindopril 3.

Key Features of ACE Inhibitor-Induced GI Angioedema:

• Presentation: Abdominal pain with nausea, vomiting, and/or diarrhea
• Timing: Unpredictable—can occur within weeks or after years of therapy 5
• Imaging findings: Small bowel wall thickening and ascites on CT scan 3, 4
• Demographics: Increased incidence in African American women 3
• Resolution: Symptoms typically improve within 48-72 hours after drug discontinuation 4

Rare Collagenous Colitis

A single case report documented perindopril-induced collagenous colitis with chronic diarrhea and hypokalemia 6. The patient developed diarrhea 3 weeks after starting perindopril, with resolution within 3 days of discontinuation and histologic normalization at 4 months.

Clinical Management Algorithm

If a patient on perindopril develops diarrhea:

1. Mild, isolated diarrhea (no other symptoms):

   • Consider symptomatic management
   • Monitor for persistence or worsening
   • Rule out other causes (infections, dietary changes, other medications)

2. Diarrhea with abdominal pain, nausea, or vomiting:

   • Immediately consider ACE inhibitor-induced GI angioedema
   • Obtain CT abdomen/pelvis looking for small bowel wall thickening and ascites
   • Discontinue perindopril immediately if imaging suggests angioedema
   • Provide supportive care with IV fluids
   • Symptoms should improve within 48 hours if drug-related

3. Chronic diarrhea with hypokalemia:

   • Consider colonoscopy with biopsies to evaluate for microscopic colitis
   • Discontinue perindopril if collagenous colitis confirmed

Important Caveats

• Do not rechallenge with perindopril or any other ACE inhibitor if GI angioedema is diagnosed—recurrence is highly likely 3
• Consider switching to an angiotensin receptor blocker (ARB) as an alternative, though cross-reactivity can rarely occur
• The FDA label warns that inadequate fluid intake or excessive diarrhea can lead to excessive blood pressure drops in patients on ACE inhibitors 1
• African American women appear at higher risk for GI angioedema 3

Bottom line: While simple diarrhea from perindopril is uncommon and usually mild, any patient on perindopril presenting with diarrhea plus abdominal pain should be evaluated urgently for potentially serious GI angioedema, which requires immediate drug discontinuation.