Lisinopril and Canrenoate: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Canrenoate
No brand names on recordLisinopril
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Both of these medicines can raise the potassium level in your blood. Canrenoate is a "potassium-sparing" water pill, which means it helps your body hold onto potassium. Lisinopril, a blood pressure medicine, lowers a hormone called aldosterone, which also makes you keep more potassium. Used together, they can push your potassium higher than either one alone.
Too much potassium can affect your heartbeat, so this matters. The good news is your care team knows about this combination and can manage it easily with simple blood tests. Please keep taking both as prescribed, and let your doctor or pharmacist know if you feel unusually weak, tired, or notice a slow or irregular heartbeat.
Additive hyperkalemia risk. Lisinopril (ACE inhibitor) suppresses aldosterone, reducing renal potassium excretion; canrenoate (an aldosterone antagonist, the active metabolite of spironolactone) further blocks aldosterone-mediated potassium excretion. The effect is pharmacodynamic, not a prodrug or CYP issue.
- Direction/magnitude: serum K+ may rise 1 to 1.5 mEq/L versus either agent alone.
- Onset: delayed. Evidence: probable. Severity: major (rare arrhythmias/death reported).
- Monitoring: baseline and periodic serum potassium and renal function; higher vigilance in CKD, diabetes, elderly, or with other K+-raising drugs/supplements.
Dose may need individualization by the care team based on potassium trends.
What happens
Increased risk of hyperkalemia
Interaction Deep Dive
By reducing aldosterone, angiotensin-converting enzyme (ACE) inhibitors promote the retention of potassium1. When a potassium-sparing diuretic (spironolactone, canrenoate potassium, aMILoride, triamterene) is taken together with an ACE inhibitor, serum potassium has been reported to rise by 1 to 1.5 mEq/L relative to the level seen with either agent taken by itself23. In some instances, this elevation has led to serious arrhythmias and fatalities45.
Why it happens (mechanism)
Increased potassium retention secondary to lowered aldosterone levels
How to manage this interaction
This combination is used in practice, but it needs monitoring. Your care team manages it by checking your blood.
- Keep taking both exactly as prescribed unless your prescriber tells you otherwise.
- Expect periodic blood tests for potassium and kidney function; your doses may be adjusted and individualized based on the results.
- Avoid extra potassium (salt substitutes, potassium supplements) unless your care team approves.
- Report symptoms like muscle weakness, tingling, fatigue, or a slow/irregular heartbeat promptly.
Ask your pharmacist or doctor before adding any new medicine or supplement.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) A study assessed the safety of combining an ACE inhibitor (captopril) with a thiazide/potassium-sparing diuretic in 332 hypertensive patients whose blood pressure had failed to normalize on the diuretics alone. Only a single case of hyperkalemia (6 mmol/liter) was observed, along with a very low rate of hypotension (1.6%) 6.
b) The consequences of adding spironolactone to an ACE inhibitor and a loop diuretic were examined in 214 patients with severe chronic congestive heart failure. Patients were randomized into one of five parallel treatment arms: placebo or spironolactone given as a single daily dose of 12.5 mg, 25 mg, 50 mg, or 75 mg over 12 weeks. Hypokalemia (serum potassium below 3.4 mmol/L) was seen in 10% of patients receiving placebo and in 0.5% of those receiving spironolactone. Hyperkalemia (serum potassium at or above 5.5 mmol/L) occurred in 5% of the placebo group, compared with 5%, 13%, 20%, and 24% in the 12.5-, 25-, 50-, and 75-mg spironolactone groups, respectively. Factors predicting hyperkalemia included the use of ACE inhibitors other than captopril, the ACE inhibitor dose, and elevated baseline serum creatinine or potassium levels. The authors concluded that daily doses of 12.5 mg to 25 mg of spironolactone given together with conventional therapy consisting of ACE inhibitors, loop diuretics, and digitalis are relatively safe, as long as serum potassium levels are monitored 7.
Common questions
Can I take Lisinopril and Canrenoate together?
Taking canrenoate and lisinopril together can raise your blood potassium to potentially dangerous levels, so your care team will monitor your potassium with regular blood tests. Keep taking both as prescribed and report weakness or an irregular heartbeat. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lisinopril and Canrenoate interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How is the Lisinopril and Canrenoate interaction managed?
This combination is used in practice, but it needs monitoring. Your care team manages it by checking your blood. Keep taking both exactly as prescribed unless your prescriber tells you otherwise. Expect periodic blood tests for potassium and kidney function; your doses may be adjusted and individualized based on the results. Avoid extra potassium (salt substitutes, potassium supplements) unless yo… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Lisinopril or Canrenoate need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (7)
- Product Information: Prinivil(R), lisinopril. Merck & Co. Inc. Whitehouse Station, NJ, 2003. DailyMed
- Armayor GM & Lopez LM: Lisinopril: a new angiotensin-converting enzyme inhibitor. Drug Intell Clin Pharm 1988; 22:365-372. PubMed
- Burnakis TG & Mioduch HJ: Combined therapy with captopril and potassium supplementation. A potential for hyperkalemia. Arch Intern Med 1984; 144:2371-2372. DOI
- Lakhani M: Complete heart block induced by hyperkalemia associated with treatment with a combination of captopril and spironolactone (letter). Br Med J 1986; 293:271.
- Johnston RT, de Bono DP, & Nyman CR: Preventable sudden death in patients receiving angiotensin converting enzyme inhibitors and loop/potassium sparing diuretic combinations. Int J Cardiol 1992; 34:213-215. PubMed
- Schohn DC, Spiesser R, Wehrlen M, et al: Aldactazine/captopril combination, safe and effective in mild to moderate systemic hypertension: report on a multicenter study of 967 patients. Am J Cardiol 1990; 65:4K-6K. PubMed
- Anon: Effectiveness of spironolactone added to an angiotensin-converting enzyme inhibitor and a loop diuretic for severe chronic congestive heart failure (The Randomized Aldactone Evaluation Study (RALES)). Am J Cardiol 1996; 78:902-907.
Keep reading about Canrenoate
Keep reading about Lisinopril
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