Acarbose and Chlorothiazide: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 10, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Chlorothiazide
Acarbose
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.
What's going on: Chlorothiazide (Diuril) is a water pill. One of its known side effects is that it can nudge your blood sugar upward. Acarbose (Precose) is a diabetes medicine that helps keep blood sugar down. So the water pill may work against your diabetes control, and your blood sugar could run higher than usual.
The good news is this is very manageable. Please keep taking both medicines exactly as prescribed. Your care team can check your blood sugar a bit more often and fine-tune your diabetes medicine if needed, especially if the water pill is ever started or stopped. Talk with your pharmacist or doctor if you notice higher readings.
Effect: Chlorothiazide, a thiazide diuretic, may impair glucose tolerance and raise blood glucose, potentially reducing glycemic control achieved with acarbose and altering (usually increasing) antidiabetic/insulin requirements.
Mechanism: Altered glucose metabolism (thiazide-induced hyperglycemia); this is a PD interaction, not a CYP or transporter effect. Neither agent is metabolically activated in a way that reverses direction.
- Direction: Reduced net antidiabetic effect / hyperglycemia risk
- Onset: Unspecified
- Evidence: Theoretical
- Management: Monitor glucose more frequently, including on diuretic withdrawal; individualize/adjust antidiabetic or insulin dosing per response.
What happens
An increased risk of hyperglycemia and an increased insulin requirement
Interaction Deep Dive
Some diuretics can affect glucose tolerance or blood sugar concentrations, which may make a patient more susceptible to hyperglycemia or a loss of glycemic control. The need for insulin might rise123, fall, or remain the same4. When a particular diuretic must be given together with an antidiabetic drug, monitor glucose values more often, including when the diuretic is discontinued56. Adjusting the dose of oral antidiabetic drugs or insulin may become necessary78.
Why it happens (mechanism)
Altered glucose metabolism
How to manage this interaction
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. This interaction is manageable with monitoring.
- Your care team may check your blood sugar more often while you take these together.
- Watch especially when the water pill (chlorothiazide) is started, changed, or stopped, since your sugar readings can shift.
- Your acarbose or insulin dose may need to be adjusted and individualized by your care team based on your readings.
- Tell your pharmacist or doctor if you notice consistently higher blood sugar or symptoms like increased thirst or frequent urination.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acarbose and Chlorothiazide together?
Chlorothiazide can raise blood sugar and partly offset acarbose, so your blood sugar may run higher; keep taking both, monitor your glucose more closely, and let your care team adjust your diabetes medicine as needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acarbose and Chlorothiazide interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Acarbose and Chlorothiazide interaction managed?
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. This interaction is manageable with monitoring. Your care team may check your blood sugar more often while you take these together. Watch especially when the water pill (chlorothiazide) is started, changed, or stopped, since your sugar readings can shift. Your acarbose or insulin dose may need to be adjusted and 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.
Questions for your pharmacist
- Does my dose of Acarbose or Chlorothiazide 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 (8)
- Product Information: TOUJEO(R) subcutaneous injection, insulin glargine subcutaneous injection. sanofi-aventis (per manufacturer), Bridgewater, NJ, 2015. DailyMed
- Product Information: Tresiba subcutaneous injection solution, insulin degludec subcutaneous injection solution. Novo Nordisk A/S (per EMA), Bagsvaerd, Denmark, 2013. DailyMed
- Product Information: SEMGLEE(R) subcutaneous injection, insulin glargine-yfgn subcutaneous injection. Mylan Pharmaceuticals Inc (per FDA), Morgantown, WV, 2023. DailyMed
- Product Information: chlorthalidone oral tablets, chlorthalidone oral tablets. Pliva,Inc, East Hanover, NJ, 2004. DailyMed
- Product Information: XIGDUO(TM) XR oral extended release tablets, dapagliflozin metformin HCl oral extended release tablets. AstraZeneca Pharmaceuticals LP (per manufacturer), Wilmington, DE, 2014. DailyMed
- Product Information: GLUMETZA(R) oral extended-release tablets, metformin HCl oral extended-release tablets. Santarus, Inc. (per Manufacturer), San Diego, CA, 2013. DailyMed
- Product Information: ACCURETIC(TM) oral tablets, quinapril HCl hydrochlorothiazide oral tablets. Parke-Davis (per FDA), New York, NY, 2015.
- Product Information: DYRENIUM(R) oral capsules, triamterene oral capsules. Wellspring Pharmaceutical Corporation, Ontario, Canada, 2005. DailyMed
Keep reading about Chlorothiazide
Keep reading about Acarbose
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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