Sultamicillin and Atenolol: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 15, 2026 · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Atenolol
Sultamicillin
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
You're taking atenolol (a blood pressure and heart medicine) along with sultamicillin, an antibiotic that is closely related to ampicillin. Studies show this type of antibiotic can lower how much atenolol your body absorbs, which may make the atenolol work a little less well. In practice, this effect is small, and doctors haven't found it to cause real problems for most people.
The good news is this is easy to keep an eye on. Your care team can simply check your blood pressure and adjust your atenolol dose if needed. Keep taking both as prescribed, and let your pharmacist or doctor know if your blood pressure readings creep up.
Effect: Reduced atenolol effectiveness via decreased oral bioavailability. Sultamicillin is a mutual prodrug of ampicillin and sulbactam; ampicillin has been shown to reduce atenolol serum concentrations and AUC in 2 studies, with a dose-dependent effect (greater reduction with 1 g vs 250 mg).
- Direction: Decreased atenolol exposure / attenuated beta-blockade (PD reduction).
- Onset: Rapid.
- Evidence: Probable; clinical significance not established.
- Severity: Minor.
- Management: Monitor blood pressure (and heart rate) during concurrent use; individualize atenolol dose if response is inadequate.
What happens
Decreased atenolol effectiveness
Interaction Deep Dive
Taking ampicillin together with atenolol has been shown to lower atenolol serum levels in two studies, although the clinical relevance of this effect remains unproven12. When ampicillin was given at a higher dose (1 g rather than 250 mg), the reduction in atenolol's AUC was more pronounced2.
Why it happens (mechanism)
Decreased atenolol bioavailability
How to manage this interaction
This is considered a minor interaction, and it is easily managed. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
- Your care team may monitor your blood pressure (and possibly your heart rate) while you are on the antibiotic.
- If your blood pressure runs higher than usual, your atenolol dose may be adjusted and individualized by your doctor.
- Sultamicillin is usually a short course, so any effect is temporary.
Tell your pharmacist or prescriber if you notice higher blood pressure readings or your symptoms return.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) Atenolol pharmacokinetics were investigated in 6 healthy subjects who received 100 mg of atenolol as monotherapy over 6 days. The same subjects also received atenolol 100 mg together with 1 g ampicillin, 500 mg aspirin, and 300 mg allopurinol. Allopurinol and aspirin did not meaningfully change the kinetics of atenolol, whereas ampicillin lowered the bioavailability, mean peak plasma levels, mean steady-state concentration, urinary recovery, and the area under the plasma concentration-time curve. Exercise tachycardia was significantly greater with the ampicillin plus atenolol combination than with atenolol given alone 1.
Common questions
Can I take Sultamicillin and Atenolol together?
The antibiotic sultamicillin may slightly reduce how well atenolol works by lowering its absorption, but the effect is minor; just have your blood pressure monitored and your dose adjusted if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Sultamicillin and Atenolol interaction?
It is rated minor. Usually limited clinical impact.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How is the Sultamicillin and Atenolol interaction managed?
This is considered a minor interaction, and it is easily managed. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Your care team may monitor your blood pressure (and possibly your heart rate) while you are on the antibiotic. If your blood pressure runs higher than usual, your atenolol dose may be adjusted and individualized by your doctor. Sultamicillin… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Sultamicillin or Atenolol need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (2)
Keep reading about Atenolol
Keep reading about Sultamicillin
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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