Drug interactions
Chlorthalidone + Tolbutamide
Severity: Minor
Chlorthalidone and Tolbutamide: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Thiazide-type diuretics such as chlorthalidone can raise blood glucose and reduce the glucose-lowering effect of sulfonylureas. Glycemic control may worsen, particularly at higher diuretic doses or with potassium depletion.
What this interaction means in plain words
Chlorthalidone and Tolbutamide have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Chlorthalidone belongs to Cardiovascular; Tolbutamide belongs to Endocrine.
Why it happens
Thiazide-induced hypokalemia and reduced insulin secretion and sensitivity oppose the hypoglycemic action of tolbutamide (pharmacodynamic antagonism).
What to do
Monitor blood glucose and HbA1c after starting or changing chlorthalidone and adjust the antidiabetic dose if needed. Correct hypokalemia.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Chlorthalidone
Other interactions of Tolbutamide
- Glyburide-metformin + Tolbutamide Major
- Insulin degludec-liraglutide + Tolbutamide Major
- Aceclofenac + Tolbutamide Moderate
- Acemetacin + Tolbutamide Moderate
- Acetylsalicylic acid + Tolbutamide Moderate
- Albiglutide + Tolbutamide Moderate
Frequently asked questions
Can I take Chlorthalidone with Tolbutamide?
MediHelp rates the interaction as minor. Chlorthalidone and Tolbutamide have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Thiazide-type diuretics such as chlorthalidone can raise blood glucose and reduce the glucose-lowering effect of sulfonylureas. Glycemic control may worsen, particularly at higher diuretic doses or with potassium depletion.
How serious is the interaction between Chlorthalidone and Tolbutamide?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood glucose and HbA1c after starting or changing chlorthalidone and adjust the antidiabetic dose if needed. Correct hypokalemia.
What other medicines interact with Chlorthalidone?
MediHelp also lists interactions of Chlorthalidone with, for example, Amifostine, Atenolol-chlorthalidone, Candesartan-hydrochlorothiazide. The full list is on the Chlorthalidone page.
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