Drug interactions
Ampicillin-sulbactam + Methotrexate
Severity: Major
Ampicillin-sulbactam and Methotrexate: 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
Penicillins can raise methotrexate concentrations and prolong exposure, leading to increased myelosuppression, mucositis and other toxicity. The effect is most concerning with high-dose methotrexate or impaired renal function.
What this interaction means in plain words
Ampicillin-sulbactam and Methotrexate 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.
Ampicillin-sulbactam belongs to Anti Bacterial; Methotrexate belongs to Oncology.
Why it happens
Competition for renal tubular secretion reduces methotrexate renal clearance.
What to do
Monitor methotrexate levels, renal function and blood counts when co-administered, and consider an alternative antibiotic during high-dose methotrexate.
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 Ampicillin-sulbactam
Other interactions of Methotrexate
- Acitretin + Methotrexate Contraindicated
- Adenovirus types 4 and 7 live + Methotrexate Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Methotrexate Contraindicated
- Ketorolac + Methotrexate Contraindicated
- Measles mumps and rubella vaccine live + Methotrexate Contraindicated
- Measles mumps and rubella vaccine + Methotrexate Contraindicated
Frequently asked questions
Can I take Ampicillin-sulbactam with Methotrexate?
MediHelp rates the interaction as major. Ampicillin-sulbactam and Methotrexate 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. Penicillins can raise methotrexate concentrations and prolong exposure, leading to increased myelosuppression, mucositis and other toxicity. The effect is most concerning with high-dose methotrexate or impaired renal function.
How serious is the interaction between Ampicillin-sulbactam and Methotrexate?
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 methotrexate levels, renal function and blood counts when co-administered, and consider an alternative antibiotic during high-dose methotrexate.
What other medicines interact with Ampicillin-sulbactam?
MediHelp also lists interactions of Ampicillin-sulbactam with, for example, Allopurinol, Bcg vaccine live, Chloramphenicol. The full list is on the Ampicillin-sulbactam page.
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