Methenamine Mandelate 500 mg/5mL Solution, 473 mL
🆔 Identity & classification
Where does this data come from?
🏷️ RxNorm drug class
This medicine belongs to the Other antibacterials class.
Where does this data come from?
🏭 Manufacturer & labeler
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🩺 Clinical
Methenamine, an antibiotic, eliminates bacteria that cause urinary tract infections. It usually is used on a long-term basis to treat chronic infections and to prevent recurrence of infections. Antibiotics will not work for colds, flu, or other viral infections. This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
Read the full MedlinePlus article ↗- That's a great question. Methenamine isn't used to clear an active infection — it's used to prevent another one from taking hold. Once your other antibiotic has done that job, meth...
- Why do I need to take methenamine if my infection is already gone?
- Yes, it actually does. Methenamine only converts into its active antibacterial form in acidic urine. Foods and medications that make your urine more alkaline — less acidic — can re...
- Does it matter what I eat or drink while I'm on this medication?
Patient education
Supplement & herbal interactions
Some supplements/herbs that may interact with Methenamine Mandelate — tap one for details:
Methenamine Mandelate may be associated with lower levels of 7 nutrients — worth a chat with your pharmacist, not a cause for alarm.
Where does this data come from?
Ask a licensed pharmacist directly — free, answered by our team.
🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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UNII LKG8494WBH
Benzyl alcohol is a clear liquid used as a preservative and solvent in medicines. It helps prevent bacterial and fungal growth and dissolves other ingredients to create uniform liquid formulations.
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UNII SB8ZUX40TY
Saccharin sodium is an artificial sweetener made from saccharin salt. It's added to medicines to improve taste, especially in liquid formulations for children or bitter drugs.
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UNII 059QF0KO0R
Water is a liquid solvent that dissolves and mixes ingredients together in liquid medicines, syrups, and injections. It helps distribute the active drug evenly throughout the product.
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UNII TTV12P4NEE
Xanthan gum is a thickening and stabilizing ingredient made from fermented corn or other sugars. It's added to medicines to improve texture, prevent separation of liquids and solids, and help the product stay consistent.
4 inactive ingredients listed in the exact product block matched to this NDC.
Where does this data come from?
ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per mL | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | Not in the retail survey — common for institutional, discontinued, or low-volume packs. | |
| Medicaid paysCMS SDUD · 12 mo | No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data. | |
| Medicare drug plans payPart D · quarterly | No Part D plan price is available for this NDC in our data. | |
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Methenamine Mandelate 500 mg/5mLthis 85477-0115-16 | Oncora | 473 ml | — | — | FDA listed | — |
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⏳ Availability & generic status
We did not find an FDA-approved generic match for this exact strength, form and route.
Where does this data come from?
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
🔬 Reported adverse events (FAERS)
Top reported reactions
Age at onset
Reporter sex
Serious outcomes
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📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 85477-0115-16 You're viewing this | 473 mL in 1 BOTTLE (85477-115-16) | 2026-04-20 | Active |
🧭 About this NDC listing & data coverage
Listed without an FDA application
This product's marketing category indicates it is marketed without an approved FDA application (no NDA, ANDA, or BLA on file). Having an NDC does not by itself establish FDA approval — the NDC Directory is a listing system, not an approval decision. Approval-linked data such as Orange Book therapeutic-equivalence ratings therefore does not apply.
What data is (and isn’t) available for this NDC — tap to expand
| NDC identity (package / product / labeler codes) | ✓ Available |
| Labeler | ✓ Available |
| Product & package description | ✓ Available |
| Marketing category & status | ✓ Available |
| Active ingredient / dosage form / route | ✓ Available |
| FDA label (SPL via DailyMed) | ✓ Available |
| Package photos | ✓ Available |
| Inactive ingredients (structured) | ✓ Available |
| NADAC pharmacy acquisition price (CMS) | — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey. |
| Orange Book / therapeutic-equivalence data | — Not published for this NDC Applies only to products approved under an NDA/ANDA; many listings are out of scope. |
| HCPCS J-code billing crosswalk | — Not published for this NDC Most self-administered / retail products have no J-code — that is normal. |
| Medicaid utilization (CMS SDUD) | — Not published for this NDC CMS reports utilization only for NDCs with Medicaid claims above its privacy threshold. |
Questions about this listing
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Is the NDC printed on the package the same as the 11-digit billing NDC?
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📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
INDICATIONS AND USAGE Methenamine mandelate, USP is indicated for the suppression or elimination of bacteriuria associated with pyelonephritis, cystitis, and other chronic urinary tract infections; also for infected residual urine sometimes accompanying neurologic diseases. When used as recommended, methenamine mandelate, USP is particularly suitable for long-term therapy because of its safety and because resistance to the nonspecific bactericidal action of formaldehyde does not develop. Pathogens resistant to other antibacterial agents may respond to methenamine mandelate, USP because of the nonspecific effect of formaldehyde formed in an acid urine.
Prophylactic Use Rationale: Urine is a good culture medium for many urinary pathogens. Inoculation by a few organisms (relapse or reinfection) may lead to bacteriuria in susceptible individuals. Thus, the rationale of management in recurring urinary tract infection (bacteriuria) is to change the urine from a growth-supporting to a growth-inhibiting medium.
There is a growing body of evidence that long-term administration of methenamine mandelate, USP can prevent the recurrence of bacteriuria in patients with chronic pyelonephritis. T herapeutic Use Rationale: Methenamine mandelate, USP helps to sterilize the urine, and in some situations in which underlying pathologic conditions prevent sterilization by any means, it can help to suppress the bacteriuria. Methenamine mandelate, USP should not be used alone for acute infections with parenchymal involvement causing systemic symptoms such as chi ls and fever.
A thorough diagnostic investigation as a part of the overall management of the urinary tract infection should accompany the use of methenamine mandelate, USP.
⏱️ Dosage and Administration ▾
DOSAGE AND ADMINISTRATION The average adult dose is 4 g daily given as 2 teaspoon after each meal and at bedtime. Children 6 to 12 should receive half the adult dose, and children under 6 years of age should receive 250 mg per 30 lb body weight, four times daily. Since an acid urine is essential for antibacterial activity, with maximum efficacy occurring at pH 5.5 or below, restriction of alkalinizing foods and medication is thus desirable.
If testing of urine pH reveals the need, supplemental acidification should be given.
⛔ Contraindications ▾
CONTRAINDICATIONS Contraindicated in renal insufficiency. Methenamine mandelate, USP should not be used in patients who have previously exhibited hypersensitivity to it.
🤒 Adverse Reactions ▾
ADVERSE REACTIONS An occasional patient may experience gastrointestinal disturbance or a generalized skin rash. Microscopic and rarely gross hematuria have been described.
🔄 Drug Interactions ▾
DRUG INTERACTIONS Formaldehyde and sulfamethizole form an insoluble precipitate in acid urine; therefore, methenamine mandelate, USP should not be administered concurrently with sulfamethizole.
🔄 Drug / Laboratory Test Interactions ▾
DRUG & OR LABORATORY TEST INTERACTIONS Formaldehyde interferes with fluorometric procedures for determination of urinary catecholamines and vani lylmandelic acid (VMA), causing erroneously high results. Formaldehyde also causes falsely decreased urine estriol levels by reacting with estriol when acid hydrolysis techniques are used; estriol determinations which use enzymatic hydrolysis are unaffected by formaldehyde. Formaldehyde causes falsely elevated 17- hydroxycorticosteroid levels when the Porter-Silber method is used and falsely decreased 5-hydroxyindoleacetic acid (5HIAA) levels by inhibiting color development when nitrosonaphthol methods are used.
🤰 Pregnancy ▾
PREGNANCY Pregnancy Category C: Animal reproduction studies have not been conducted with methenamine mandelate, USP. It is also not known whether methenamine mandelate, USP can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Methenamine mandelate, USP should be given to a pregnant woman only if clearly needed.
Since introduction, published reports on the use of methenamine mandelate, USP in pregnant women have not shown an increased risk of fetal abnormalities from use during pregnancy.
🧬 Clinical Pharmacology ▾
CLINICAL PHARMACOLOGY Methenamine mandelate, USP is readily absorbed but remains essentially inactive until it is excreted by the kidney and concentrated in the urine. An acid urine is essential for antibacterial action, with maximum efficacy occurring at pH 5.5 or less. In an acid urine, mandelic acid exerts its antibacterial action and also contributes to the acidification of the urine.
Mandelic acid is excreted both by glomerular filtration and tubular excretion. The methenamine component, in an acid urine, is hydrolyzed to ammonia and to the bactericidal agent formaldehyde. There is equally effective antibacterial activity against both gram-positive and gram-negative organisms, since the antibacterial action of mandelic acid and formaldehyde is nonspecific.
There are reports that methenamine mandelate, USP is ineffective in some infections with Proteus vulgaris and urea-splitting strains of Pseudomonas aeruginosa and A aerogenes . Since urea-splitting strains may raise the pH of the urine, particular attention to supplementary acidification is required. However, results in any single case will depend to a large extent on the underlying pathology and the overall management.
📦 How Supplied / Storage and Handling ▾
HOW SUPPLIED Methenamine Mandelate Oral Solution, 500 mg/5 mL, is a clear solution and available in the following oral dosage forms: NDC 85477-115-16: 16 fl oz (473 mL) bottle Store at controlled room temperature between 20°-25°C (68°-77°F); excursions permitted to 15°-30°C (59°-86°F) [See USP controlled Room Temperature]. Dispense in a tight, light-resistant container as defined in the USP.
📋 Description ▾
DESCRIPTION Methenamine mandelate, USP, a urinary antibacterial agent, is the chemical combination of mandelic acid with methenamine. Methenamine mandelate, USP is available for oral use as oral liquid. Each 5 mL (teaspoon) contains 500 mg Methenamine Mandelate. The oral solution also contains Sodium Saccharine, Benzyl Alcohol, Xanthan Gum, Mixed Berry Flavor and Water for Injection.