Lisinopril and Piretanide: 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
Piretanide
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.
Piretanide is a water pill (loop diuretic) and lisinopril is a blood pressure medicine (an ACE inhibitor). When you take these two together, especially the first dose or two of lisinopril, your blood pressure can drop suddenly when you stand up. This can make you feel dizzy, lightheaded, or like you might faint.
This happens because the water pill lowers your body's fluid, and lisinopril relaxes your blood vessels. Put together, that can be a bit much at first. The good news is this effect is usually temporary, and your care team can manage it easily by adjusting timing, doses, and keeping an eye on your blood pressure. Rise slowly from sitting or lying down for the first few days.
Effect: First-dose postural hypotension when an ACE inhibitor (lisinopril) is added to loop diuretic (piretanide) therapy. Mechanism: pharmacodynamic, not pharmacokinetic. Diuretic-induced volume/sodium depletion plus ACE-inhibitor vasodilation and RAAS suppression, producing an exaggerated hypotensive response. No clinically significant PK interaction.
- Onset: rapid (first dose)
- Evidence: probable; severity moderate
- Caveat: ACE inhibitors may paradoxically reduce GFR/natriuresis, risking fluid retention
Management: If feasible, hold the diuretic 2 to 3 days before initiating the ACE inhibitor; otherwise start a very low ACE-inhibitor dose in the evening with BP monitoring for 4 hours post-dose. Monitor BP, volume status, and weight for up to 2 weeks after any dose change.
What happens
Postural hypotension (first dose)
Interaction Deep Dive
The introduction of ACE inhibitors to ongoing loop diuretic treatment has been associated with reports of severe postural hypotension. Patients who are sodium depleted or hypovolemic as a result of diuretic use or restricted sodium intake frequently experience first dose hypotension, a response that is typically transient91017. One would expect this pairing to enhance natriuresis; however, ACE inhibitors can paradoxically diminish glomerular filtration as well as the diuretic and natriuretic effects of diuretics, which may result in edema and fluid retention64. No pharmacokinetic interactions of clinical significance have been noted between these two drug classes.
Why it happens (mechanism)
Vasodilation and relative intra-vascular volume depletion
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Your care team knows how to handle this combination.
- They may space out the start of the two drugs, or begin lisinopril at a very low dose, often in the evening.
- They will likely monitor your blood pressure closely, especially in the first hours after your first lisinopril dose and over the next couple of weeks.
- They may also check your fluid status and weight after any dose changes.
Tell your pharmacist or doctor if you feel dizzy, faint, or lightheaded when standing. For now, get up slowly from sitting or lying down.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
3 reports — tap to read
a) One study found that captopril did not change the renal excretion or the diuretic action of furosemide in hypertensive patients 2. However, more recent findings show that standard doses of captopril reduce the natriuretic and diuretic effects of furosemide in patients with mild to moderate congestive heart failure. Sodium excretion rose by 623% during furosemide use; this fell to 242% when captopril was added 3. Several authors have described weight gain, sodium retention, and peripheral edema in patients receiving diuretic therapy when ACE inhibitors were started 456.
b) In a single-dose investigation, oral benazepril (10 mg) and oral furosemide (40 mg) were given separately and together to 12 healthy volunteers. No significant effects on benazepril pharmacokinetics were seen. The urinary excretion of total furosemide dropped by 10% to 20% when the drugs were given together. When each drug was given alone as a single dose, blood pressure and pulse were not significantly affected. However, a fall in erect blood pressure and a rise in pulse rate were observed with the combination. The greatest effects were seen four hours after administration (122 to 104 mm Hg and 87 to 107 beats per minute, respectively). Most subjects taking the combination experienced dizziness, which occurred together with reductions in blood pressure 7.
c) Combined captopril and furosemide therapy has been reported to enhance the hypotensive effects of captopril. In one patient with high plasma renin activity who received 50 mg captopril and intravenous furosemide, blood pressure fell sharply from 290/150 mm Hg to 135/60 mm Hg within 10 minutes 8.
Common questions
Can I take Lisinopril and Piretanide together?
Adding lisinopril to piretanide can cause a sharp drop in blood pressure with the first dose, leaving you dizzy when you stand; it is usually temporary and your care team can manage it with low starting doses and close blood pressure monitoring. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lisinopril and Piretanide interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How is the Lisinopril and Piretanide interaction managed?
Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Your care team knows how to handle this combination. They may space out the start of the two drugs, or begin lisinopril at a very low dose, often in the evening. They will likely monitor your blood pressure closely, especially in the first hours after your first lisinopril dose and over the next couple of… 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 Piretanide 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 anything you'd monitor while I'm on both?
References (10)
- Vlasses PH, Ferguson RK, & Chatterjee K: Captopril: clinical pharmacology and benefit-to-risk ratio in hypertension and congestive heart failure. Pharmacotherapy 1982; 2:1-17. PubMed
- Fujimura A, Shimokawa Y, & Ebihara A: Influence of captopril on urinary excretion of furosemide in hypertensive subjects. J Clin Pharmacol 1990; 30:538-542. PubMed
- McLay JS, McMurray JJ, Bridges AB, et al: Acute effects of captopril on the renal actions of furosemide in patients with chronic heart failure. Am Heart J 1993; 126:879-886. PubMed
- Cleland JGF, Gillen G, & Dargie HJ: The effects of frusemide and angiotensin-converting enzyme inhibitors and their combination on cardiac and renal haemodynamics in heart failure. Eur Heart J 1988; 9:132-141. PubMed
- Odemuyiwa O, Gilmartin J, Kenny D, et al: Captopril and the diuretic requirements in moderate and severe chronic heart failure. Eur Heart J 1989; 10:586-590. PubMed
- Flapan AD, Davies E, Waugh C, et al: Acute administration of captopril lowers the natriuretic and diuretic response to a loop diuretic in patients with chronic cardiac failure. Eur Heart J 1991; 12:924-927. PubMed
- De Lepeleire I, Van Hecken A, Verbesselt R, et al: Interaction between furosemide and the converting enzyme inhibitor benazepril in healthy volunteers. Eur J Clin Pharmacol 1988; 34:465-468. PubMed
- Case DB, Atlas SA, Laragh JH, et al: Clinical experience with blockade of the renin-angiotensin-aldosterone system by an oral converting-enzyme inhibitor (SQ 14,255, captopril) in hypertensive patients. Prog Cardiovasc Dis 1978; 21:195-206.
- Clementy J, Schwebig A, Mazaud C, et al: Comparative study of the efficacy and tolerance of Capozide and Moduretic administered in a single daily dose for the treatment of chronic moderate arterial hypertension. Postgrad Med J 1986; 62(suppl 1):132.
- Gluck Z, Beretta-Piccoli C, & Reubi FC: Long-term effects of captopril on renal function in hypertensive patients. Eur J Clin Pharmacol 1984; 26:315-323. PubMed
Keep reading about Piretanide
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