Drug interactions
Chlorothiazide + Insulin glargine
Severity: Minor
Chlorothiazide and Insulin glargine: 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 effectiveness of insulin, so insulin needs may increase.
What this interaction means in plain words
Chlorothiazide and Insulin glargine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Chlorothiazide belongs to Cardiovascular; Insulin glargine belongs to Endocrine.
Why it happens
Thiazides impair glucose tolerance, partly through hypokalemia reducing insulin secretion, and may increase insulin resistance.
What to do
Monitor glucose and potassium after starting chlorothiazide and increase the insulin dose if needed.
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 Insulin glargine
Other interactions of Chlorothiazide
Frequently asked questions
Can I take Chlorothiazide with Insulin glargine?
MediHelp rates the interaction as minor. Chlorothiazide and Insulin glargine 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 effectiveness of insulin, so insulin needs may increase.
How serious is the interaction between Chlorothiazide and Insulin glargine?
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 glucose and potassium after starting chlorothiazide and increase the insulin dose if needed.
What other medicines interact with Insulin glargine?
MediHelp also lists interactions of Insulin glargine with, for example, Alogliptin-pioglitazone, Ethanol, Glimepiride-pioglitazone. The full list is on the Insulin glargine page.
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