Drug interactions
Chlorpropamide + Sulfadiazine
Severity: Major
Chlorpropamide and Sulfadiazine: major 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
Sulfonamide antibiotics can potentiate sulfonylureas and have caused hypoglycemia, sometimes severe. Chlorpropamide's long half-life makes episodes prolonged.
What this interaction means in plain words
Chlorpropamide and Sulfadiazine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Sulfadiazine inhibits CYP2C9 and displaces chlorpropamide from protein binding, raising free drug levels.
What to do
Monitor blood glucose closely and consider reducing the chlorpropamide dose during the antibiotic course. Prefer a non-sulfonamide antibiotic if possible.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Chlorpropamide
Frequently asked questions
Can I take Chlorpropamide with Sulfadiazine?
MediHelp rates the interaction as major. Chlorpropamide and Sulfadiazine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Sulfonamide antibiotics can potentiate sulfonylureas and have caused hypoglycemia, sometimes severe. Chlorpropamide's long half-life makes episodes prolonged.
How serious is the interaction between Chlorpropamide and Sulfadiazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood glucose closely and consider reducing the chlorpropamide dose during the antibiotic course. Prefer a non-sulfonamide antibiotic if possible.
What other medicines interact with Chlorpropamide?
MediHelp also lists interactions of Chlorpropamide with, for example, Ethanol, Exenatide, Insulin degludec-insulin aspart. The full list is on the Chlorpropamide page.
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