Drug interactions
Ampicillin-sulbactam + Doxycycline
Severity: Moderate
Ampicillin-sulbactam and Doxycycline: 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
Bacteriostatic tetracyclines may blunt the bactericidal activity of beta-lactams, which depend on actively growing bacteria. Clinical evidence is mostly from older studies in serious infections such as meningitis.
What this interaction means in plain words
Ampicillin-sulbactam and Doxycycline 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.
Ampicillin-sulbactam belongs to Anti Bacterial; Doxycycline belongs to Anti Bacterial.
Why it happens
Tetracycline-induced inhibition of bacterial protein synthesis and growth reduces beta-lactam killing, which requires cell wall synthesis.
What to do
Avoid the combination in severe infections such as meningitis or endocarditis where bactericidal activity is essential. Otherwise monitor clinical response.
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 Ampicillin-sulbactam
Other interactions of Doxycycline
- Acitretin + Doxycycline Contraindicated
- Aminolevulinic acid + Doxycycline Major
- Cholera vaccine + Doxycycline Major
- Doxycycline + Isotretinoin Major
- Doxycycline + Methoxyflurane Major
- Doxycycline + Microbiota Major
Frequently asked questions
Can I take Ampicillin-sulbactam with Doxycycline?
MediHelp rates the interaction as moderate. Ampicillin-sulbactam and Doxycycline 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. Bacteriostatic tetracyclines may blunt the bactericidal activity of beta-lactams, which depend on actively growing bacteria. Clinical evidence is mostly from older studies in serious infections such as meningitis.
How serious is the interaction between Ampicillin-sulbactam and Doxycycline?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination in severe infections such as meningitis or endocarditis where bactericidal activity is essential. Otherwise monitor clinical response.
What other medicines interact with Ampicillin-sulbactam?
MediHelp also lists interactions of Ampicillin-sulbactam with, for example, Methotrexate, Allopurinol, Bcg vaccine live. The full list is on the Ampicillin-sulbactam page.
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