Drug interactions
Chlorpropamide + Sulfisoxazole
Severity: Major
Chlorpropamide and Sulfisoxazole: 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
Sulfisoxazole can potentiate sulfonylurea action and has been associated with hypoglycemia. The effect on long-acting chlorpropamide may be prolonged.
What this interaction means in plain words
Chlorpropamide and Sulfisoxazole 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
Sulfisoxazole displaces chlorpropamide from plasma proteins and inhibits CYP2C9.
What to do
Monitor blood glucose closely and reduce the chlorpropamide dose if needed. Use a non-sulfonamide antibiotic where 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 Sulfisoxazole?
MediHelp rates the interaction as major. Chlorpropamide and Sulfisoxazole 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. Sulfisoxazole can potentiate sulfonylurea action and has been associated with hypoglycemia. The effect on long-acting chlorpropamide may be prolonged.
How serious is the interaction between Chlorpropamide and Sulfisoxazole?
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 reduce the chlorpropamide dose if needed. Use a non-sulfonamide antibiotic where 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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