Home›Methenamine Sodium Phosphate Monobasic Monohydrate Phenyl Sa›Methenamine Sodium Phosphate Monobasic Monohydrate Phenyl Sa + Ketoconazole

Does Methenamine Sodium Phosphate Monobasic Monohydrate Phenyl Sa Interact with Ketoconazole?

Methenamine Sodium Phosphate Monobasic Monohydrate Phenyl Sa and Ketoconazole have a moderate drug interaction according to U.S. FDA drug labeling data. May cause increased gastrointestinal pH resulting in marked reduction in ketoconazole absorption. Take combination at least 2 hours after ketoconazole. The mechanism involves increased gastrointestinal ph reducing ketoconazole absorption. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.

Severity: Moderate
Ketoconazole Class: Azole Antifungal
Management: Monitor for effects
Data Source: U.S. FDA via OpenFDA

How This Interaction Works

The interaction between Methenamine Sodium Phosphate Monobasic Monohydrate Phenyl Sa and Ketoconazole occurs because increased gastrointestinal ph reducing ketoconazole absorption. Clinically, this means may cause increased gastrointestinal ph resulting in marked reduction in ketoconazole absorption. take combination at least 2 hours after ketoconazole. This is classified as a moderate interaction. While it may not require stopping either medication, your healthcare provider should be aware you are taking both so they can monitor for potential effects and adjust treatment if necessary.

What To Tell Your Doctor or Pharmacist

If you are taking Methenamine Sodium Phosphate Monobasic Monohydrate Phenyl Sa and your doctor is considering prescribing Ketoconazole (or vice versa), make sure to:

Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
Ask whether the benefits of combining these medications outweigh the risks for your specific situation
Ask what symptoms to watch for that would indicate the interaction is causing problems
Ask whether any dosage adjustments are needed
Never stop or change either medication without first consulting your healthcare provider

💊 Methenamine Sodium Phosphate Monobasic Monohydrate Phenyl Sa(Mb Caps)+💊 Ketoconazole(T8 Keto Flush)

Severity & Interaction Details

🟡

moderate

Be aware — moderate interaction

Documented interaction with manageable risk. May require dose adjustment or monitoring.

Severity scale

MinorContra

On record

Yes

Drug A class

—

Drug B class

Azole Antifungal

Source

NLP:methenamine, sodium phosphate, monobasic, anhydrous, phenyl salicylate, methylene blue and hyoscyamine sulfate

What this means in plain English

May cause increased gastrointestinal pH resulting in marked reduction in ketoconazole absorption. Take combination at least 2 hours after ketoconazole.

About Methenamine Sodium Phosphate Monobasic Monohydrate Phenyl Sa and Ketoconazole

Ketoconazole is an Azole Antifungal. You may recognize them by the brand names Mb Caps and Ketodan. Both medications are taken by mouth. Ketoconazole additionally carries an FDA boxed warning, the FDA's strongest safety alert.

What the FDA label says

"Increased gastrointestinal pH reducing ketoconazole absorption"

📖 Source: NLP:methenamine, sodium phosphate, monobasic, anhydrous, phenyl salicylate, methylene blue and hyoscyamine sulfate

Recent research & FDA safety updates

Live

Auto-aggregated from PubMed E-utilities and FDA safety data.

FDA

FDA Safety Alert: Albuterol Sulfate Inhalation Solution, 0.5%, 25 mg/5 mL (5 mg/mL*), 30x5 mL Sterile Unit-Dose Vials,about Methenamine Sodium Phosphate Monobasic Monohydrate Phenyl Sa · 2026-04

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Data integrity: Every interaction shown is extracted directly from official U.S. FDA drug labeling via openFDA and the U.S. National Library of Medicine (NIH) — no interactions are invented, inferred, or manually edited. Maintained by CheckDrugInteractions.com. See our methodology or report a correction at support@checkdruginteractions.com.

Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine, supplemented with a small number of well-established interactions from curated clinical references. For informational purposes only. Always consult your pharmacist or physician.