Drug Interaction Report

Sodium Bicarbonate and Cefpodoxime: Interaction Details

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Sodium Bicarbonate

Alka-Seltzer® Heartburn Desempacho Neut brand of sodium bicarbonate
+

Cefpodoxime

Banan® Cefpoderm Dermaceph Simplicef Vantin®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Updated Aug 8, 2026
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Interaction severity
Moderate
Can be significant — usually manageable with monitoring.
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.

Of 26 documented Sodium Bicarbonate interactions, 12 are rated moderate — including this one.
Onset
rapid
Evidence
theoretical
Severity
Moderate

What happens

Decreased cefpodoxime effectiveness

Interaction Deep Dive

Absorption of cefpodoxime may be impaired if aluminum, calcium, or magnesium containing products are coadministered. Drugs that raise gastric pH reduce peak cefpodoxime concentrations. Administration of cefpodoxime with either aluminum hydroxide (120 mL) or sodium bicarbonate (12.6 g) significantly reduced the peak concentration and AUC compared to administration during fasting or with food1. A 40% decrease in the AUC of cefpodoxime has been reported when administered after two doses of an aluminum-magnesium antacid 2.

Why it happens (mechanism)

Decreased cefpodoxime absorption

Literature reports

1 report — tap to read

a) Concomitant administration of high doses of antacids (sodium bicarbonate and aluminum hydroxide) and cefpodoxime reduces peak plasma levels of cefpodoxime by 24% to 42% and the extent of absorption by 27% to 32% 3.

Common questions

Can I take Sodium Bicarbonate and Cefpodoxime together?

Decreased cefpodoxime effectiveness Always confirm with your pharmacist or prescriber before making any change.

How serious is the Sodium Bicarbonate and Cefpodoxime interaction?

It is rated moderate. Can be significant — usually manageable with monitoring.

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 strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

  • Does my dose of Sodium Bicarbonate or Cefpodoxime 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 (3)

  1. Hughes GS, Heald DL, Barker KB, et al: The effects of gastric pH and food on the pharmacokinetics of a new oral cephalosporin, cefpodoxime proxetil. Clin Pharmacol Ther 1989; 46:674-685. DOI
  2. Saathoff N, Lode H, Neider K, et al: Pharmacokinetics of cefpodoxime proxetil and interactions with an antacid and an H2 receptor antagonist. Antimicrob Agents Chemother 1992; 36:796-800. PubMed
  3. Product Information: Vantin(R), cefpodoxime. Pharmacia & Upjohn Company, Kalamazoo, MI, 2000. DailyMed
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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.