Drug interactions
Chlorothiazide + Tolbutamide
Severity: Moderate
Chlorothiazide and Tolbutamide: moderate 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 diuretics can raise blood glucose and may blunt the effect of sulfonylureas, so glycemic control can worsen after a thiazide is added.
What this interaction means in plain words
Chlorothiazide and Tolbutamide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Chlorothiazide belongs to Cardiovascular; Tolbutamide belongs to Endocrine.
Why it happens
Thiazide-induced hypokalemia and reduced insulin secretion and sensitivity oppose tolbutamide.
What to do
Monitor blood glucose and potassium when chlorothiazide is started. Adjust the tolbutamide dose if needed and correct hypokalemia.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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
Other interactions of Chlorothiazide
Frequently asked questions
Can I take Chlorothiazide with Tolbutamide?
MediHelp rates the interaction as moderate. Chlorothiazide and Tolbutamide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Thiazide diuretics can raise blood glucose and may blunt the effect of sulfonylureas, so glycemic control can worsen after a thiazide is added.
How serious is the interaction between Chlorothiazide and Tolbutamide?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood glucose and potassium when chlorothiazide is started. Adjust the tolbutamide dose if needed and correct hypokalemia.
What other medicines interact with Tolbutamide?
MediHelp also lists interactions of Tolbutamide with, for example, Glyburide-metformin, Insulin degludec-liraglutide, Aceclofenac. The full list is on the Tolbutamide page.
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