Drug Interaction Report

Sodium Bicarbonate and Ketoconazole Topical: Interaction Details

Name: Sodium Bicarbonate and Ketoconazole Topical Interaction
Creator: Dr. Brian Staiger, PharmD, BCPS

A pharmacist-reviewed analysis of the Sodium Bicarbonate and Ketoconazole Topical interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

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

Ketoconazole Topical

Extina® Foam Ketozole® Cream Kuric Nizoral AD® Shampoo Nizoral® Cream Nizoral® Shampoo Xolegel®

Sodium Bicarbonate

Alka-Seltzer® Heartburn Desempacho Neut brand of sodium bicarbonate

Medically reviewed by

Dr. Brian Staiger, PharmD, BCPS

Updated Aug 8, 2026

Editorial policy · Data sources

Interaction severity

Major

Potentially serious — often needs a change or close monitoring.

Minor

Moderate

Major

Contraindicated

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, 14 are rated major — including this one.

Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.

Onset

unspecified

Evidence

probable

Severity

Major

What happens

Reduced ketoconazole exposure and reduced efficacy of ketoconazole

Interaction Deep Dive

Caution is advised when using ketoconazole together with antacids such as aluminum hydroxide as coadministration may reduce ketoconazole plasma concentrations leading to a loss of ketoconazole therapeutic effect. If concomitant use is required, administer the antacid at least 1 hour before or 2 hours after ketoconazole administration. Monitor antifungal activity closely, an increase in ketoconazole dose may be indicated². Concurrent administration of ketoconazole with aluminum-, calcium- or magnesium-containing products or sodium bicarbonate has resulted in a decrease in both the Cmax and AUC of ketoconazole ¹⁴.

Why it happens (mechanism)

Changes in gastric pH; reduced ketoconazole absorption

Literature reports

2 reports — tap to read

a) An uncontrolled study was done in 10 fasting patients, with four patients given 200 mg of ketoconazole and 30 mL of Maalox(R), concomitantly. Their results showed a decrease in absorption but not to a significant degree ¹⁴.

b) Since ketoconazole is a dibasic compound, sufficient gastric acid is required for dissolution and absorption. Therefore drugs which markedly reduce gastric acidity, such as antacids, result in lower plasma concentrations of ketoconazole if administered concomitantly ³.

Common questions

Can I take Sodium Bicarbonate and Ketoconazole Topical together?

Reduced ketoconazole exposure and reduced efficacy of ketoconazole Always confirm with your pharmacist or prescriber before making any change.

How serious is the Sodium Bicarbonate and Ketoconazole Topical interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

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 Sodium Bicarbonate or Ketoconazole Topical 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 a safer alternative to one of these medications for me?

References (4)

Brass C, Galgiani JN, Blaschke TF, et al: Disposition of ketoconazole, an oral antifungal, in humans. Antimicrob Agents Chemother 1982; 21:151-158. PubMed
Product Information: Ketoconazole oral tablet, ketoconazole oral tablet. Taro Pharmaceuticals U.S.A. Inc. (per DailyMed), Hawthorne, NY, 2024. DailyMed
Van der Meer JWM, Keuning JJ, Scheijgrond HW, et al: The influence of gastric acidity on the bioavailability of ketoconazole. J Antimicrob Chemother 1980; 6:552-554.
Carlson JA, Mann HJ, & Canafax DM: Effect of pH on disintegration and dissolution of ketoconazole tablets. Am J Hosp Pharm 1983; 40:1334-1336. DOI

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Ketoconazole Topical

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All Ketoconazole Topical interactions (546) Ketoconazole Topical drug information

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Sodium Bicarbonate

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All Sodium Bicarbonate interactions (26) Sodium Bicarbonate drug information

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HelloPharmacist doesn't license one of the big commercial interaction databases, so what you'll find here is not a complete list of every known drug interaction. Instead, each entry is researched, analyzed, and written up individually — documented from the published literature, reviewed by a pharmacist, and cited so you can check every source yourself.

If a combination isn't listed here, it means we haven't documented it yet — never that it's safe. For screening a full medication list, we recommend pairing this site with a comprehensive tool like the Drugs.com Interaction Checker and, most importantly, a review by your own pharmacist. For a deep, plain-English, fully sourced explanation of a specific documented interaction — that's exactly what we built this for.

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.