Lisinopril and Tolazamide: 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
Tolazamide
Lisinopril
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.
Taking these two together may lower your blood sugar a little more than expected. Tolazamide (Tolinase) is a diabetes pill that lowers blood sugar, and lisinopril is a blood pressure medicine that can add to that effect. When blood sugar drops too low, you might feel shaky, sweaty, dizzy, or confused.
The good news is that this concern is mostly theoretical, and real-world studies did not show a big jump in serious low-sugar episodes. Please keep taking both exactly as prescribed. Just check your blood sugar as your care team suggests, and let your pharmacist or doctor know if you notice frequent lows. They can adjust things easily if needed.
Effect: Additive hypoglycemia risk when the sulfonylurea tolazamide is combined with the ACE inhibitor lisinopril. Neither drug is a prodrug in a way that alters direction; ACE inhibitors are thought to enhance insulin sensitivity, potentiating the glucose-lowering effect.
- Direction: Increased hypoglycemic effect.
- Mechanism: Unknown/proposed increased insulin sensitivity.
- Evidence: Theoretical; a self-controlled case series found no increased serious hypoglycemia with ACE inhibitors plus secretagogues (possible exception: glimepiride).
- Onset: Unspecified.
- Management: More frequent glucose monitoring during therapy and after ACE inhibitor withdrawal; antidiabetic dose may need individualized adjustment.
What happens
An increased risk of hypoglycemia
Interaction Deep Dive
Taking ACE inhibitors together with antidiabetic drugs can heighten the likelihood of hypoglycemia231. When such combined therapy cannot be avoided, glucose levels should be checked more often, not only while the patient is being treated but also once an ACE inhibitor is stopped 4. It may also be necessary to modify the insulin dose 23. According to findings from a self-controlled case series, combining ACE inhibitors with insulin secretagogues does not appear to raise the incidence of serious hypoglycemia, though glimepiride may be an exception 5.
Why it happens (mechanism)
Unknown
How to manage this interaction
Keep taking both medications as prescribed. Your care team can manage this easily with a little extra attention.
- Check your blood sugar more often, especially when you first start, change, or stop the lisinopril.
- Learn the signs of low blood sugar (shakiness, sweating, dizziness, confusion) and treat lows promptly.
- Your tolazamide dose may need to be adjusted and individualized by your care team if lows happen often.
- Report any frequent or severe low-sugar episodes to your pharmacist or prescriber so they can fine-tune your plan.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) A self-controlled case series examined Medicare claims data drawn from 5 states between 1999 and 2011 to evaluate simultaneous use of ACE inhibitors with insulin secretagogues (glimepiride, glipizide, glyburide, nateglinide, and repaglinide) or with metformin (used as a negative control). The endpoint assessed was hospital presentation for serious hypoglycemia. During the observation window, the counts of serious hypoglycemic events were 8159, 14,353, 11,129, 1595, 2901, and 32,639 for glimepiride, glipizide, glyburide, nateglinide, repaglinide, and metformin, respectively. The confounder-adjusted rate ratio (RR) was not significantly increased for glipizide, glyburide, repaglinide, or metformin, but was slightly increased for glimepiride (RR, 1.23; 95% CI, 1.11 to 1.37) and slightly decreased for nateglinide (RR, 0.73; 95% CI, 0.56 to 0.96). Aside from glimepiride, these findings indicate that concurrent use of an ACE inhibitor and insulin secretagogues was not linked to a heightened risk of serious hypoglycemia 5.
Common questions
Can I take Lisinopril and Tolazamide together?
Combining tolazamide with lisinopril may slightly increase the chance of low blood sugar, so monitor your glucose more closely and tell your care team about any frequent lows. This is manageable with monitoring and, if needed, a dose adjustment. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lisinopril and Tolazamide interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Lisinopril and Tolazamide interaction managed?
Keep taking both medications as prescribed. Your care team can manage this easily with a little extra attention. Check your blood sugar more often, especially when you first start, change, or stop the lisinopril. Learn the signs of low blood sugar (shakiness, sweating, dizziness, confusion) and treat lows promptly. Your tolazamide dose may need to be adjusted and individualized by your care team i… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
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 Tolazamide 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 (5)
- Product Information: Zestril(R) oral tablets, lisinopril oral tablets. AstraZeneca Pharmaceuticals LP (per FDA), Wilmington, DE, 2014. DailyMed
- Product Information: TOUJEO(R) subcutaneous injection, insulin glargine subcutaneous injection. sanofi-aventis (per manufacturer), Bridgewater, NJ, 2015. DailyMed
- Product Information: AFREZZA(R) oral inhalation powder, insulin human oral inhalation powder. MannKind Corporation(TM) (per manufacturer), Danbury, CT, 2014. DailyMed
- Product Information: AMARYL(R) oral tablets, glimepiride oral tablets. Sanofi-Aventis U.S. LLC (per FDA), Bridgewater, NJ, 2013. DailyMed
- Hee Nam Y, Brensinger CM, Bilker WB, et al: Angiotensin-converting enzyme inhibitors used concomitantly with insulin secretagogues and the risk of serious hypoglycemia. Clin Pharmacol Ther 2022; 111(1):218-226. PubMed
Keep reading about Tolazamide
Keep reading about Lisinopril
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