Drug interactions
Hydrochlorothiazide + Tolbutamide
Severity: Minor
Hydrochlorothiazide 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 diuretics can raise blood glucose and reduce the effect of sulfonylureas such as tolbutamide. Loss of glycemic control may occur, particularly at higher thiazide doses.
What this interaction means in plain words
Hydrochlorothiazide 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.
Hydrochlorothiazide belongs to Cardiovascular; Tolbutamide belongs to Endocrine.
Why it happens
Thiazides impair glucose tolerance via hypokalemia and reduced insulin secretion, opposing the antihyperglycemic effect (pharmacodynamic antagonism).
What to do
Monitor blood glucose when starting or changing the thiazide and increase the sulfonylurea dose or adjust therapy if control worsens.
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 Hydrochlorothiazide
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 Hydrochlorothiazide with Tolbutamide?
MediHelp rates the interaction as minor. Hydrochlorothiazide 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 diuretics can raise blood glucose and reduce the effect of sulfonylureas such as tolbutamide. Loss of glycemic control may occur, particularly at higher thiazide doses.
How serious is the interaction between Hydrochlorothiazide 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 when starting or changing the thiazide and increase the sulfonylurea dose or adjust therapy if control worsens.
What other medicines interact with Hydrochlorothiazide?
MediHelp also lists interactions of Hydrochlorothiazide with, for example, Dofetilide, Amifostine, Amiodarone. The full list is on the Hydrochlorothiazide page.
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