Drug interactions
Probenecid + Sulfamethoxazole
Severity: Moderate
Probenecid and Sulfamethoxazole: 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
Probenecid can raise and prolong sulfamethoxazole plasma concentrations. Higher exposure may increase the risk of dose-related adverse effects such as rash, hematologic effects and crystalluria.
What this interaction means in plain words
Probenecid and Sulfamethoxazole 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.
Why it happens
Probenecid inhibits renal tubular secretion of sulfonamides via organic anion transporters, reducing their renal clearance.
What to do
Monitor for sulfonamide adverse effects such as rash and cytopenias, and maintain adequate hydration. Consider reducing the sulfamethoxazole dose if toxicity appears or renal function is impaired.
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 Probenecid
- Ketorolac intranasal + Probenecid Contraindicated
- Ketorolac + Probenecid Contraindicated
- Baricitinib + Probenecid Major
- Ceftazidime / avibactam + Probenecid Major
- Methotrexate + Probenecid Major
- Pralatrexate + Probenecid Major
Frequently asked questions
Can I take Probenecid with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Probenecid and Sulfamethoxazole 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. Probenecid can raise and prolong sulfamethoxazole plasma concentrations. Higher exposure may increase the risk of dose-related adverse effects such as rash, hematologic effects and crystalluria.
How serious is the interaction between Probenecid and Sulfamethoxazole?
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 for sulfonamide adverse effects such as rash and cytopenias, and maintain adequate hydration. Consider reducing the sulfamethoxazole dose if toxicity appears or renal function is impaired.
What other medicines interact with Probenecid?
MediHelp also lists interactions of Probenecid with, for example, Ketorolac intranasal, Ketorolac, Baricitinib. The full list is on the Probenecid page.
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