Methenamine Hippurate side effects: what 1,208 FDA adverse event reports show

Methenamine Hippurate · 28 reaction terms · 391 drug–reaction co-reports · data 2026-09-14

Drug class

Not stated in label

Who reports

1,208 reports · 57% serious · 75 with death outcome · 81% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Methenamine hippurate tablets, USP is indicated for prophylactic or suppressive treatment of frequently recurring urinary tract infections when long-term therapy is considered necessary. This drug should only be used after eradication of the infection by other appropriate antimicrobial agents.

FDA label, Indications and Usage

What it is

DESCRIPTION Each white to off-white capsule shaped tablet contains 1g Methenamine Hippurate, USP which is the Hippuric Acid Salt of Methenamine (hexamethylene tetramine). The tablet also conta.

FDA label, Description section

Boxed warning

None in the current label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 20 strongest signals

Reporting / coding artifact 3No label text to screen 17

What the badges mean

Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
No label text to screen No validated FDA label was retrievable for this product, so the screen could not run. Disproportionality only.

Strongest disproportionality signals

Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 8 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Product taste abnormal	17	21.9 13.7–35.2ROR 22.2 · χ² 319 / p 1e-71	21.4 EB05 14.0 · IC025 +3.0 3/3 methods agree	Reporting / coding artifact	serious n=2	no trial data cached
Urinary tract infection (bladder infection)	163	16.6 14.4–19.2ROR 19.1 · χ² 2,395 / p <1e-300	16.6 EB05 14.5 · IC025 +3.7 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 17.3	no trial data cached
Cystitis	29	15.7 11.0–22.5ROR 16.1 · χ² 386 / p 3e-86	15.4 EB05 11.1 · IC025 +3.0 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 18.6	no trial data cached
Kidney infection	17	15.0 9.4–24.1ROR 15.2 · χ² 209 / p 1e-47	14.3 EB05 8.9 · IC025 +2.6 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 16.9	no trial data cached
Seasonal allergy	10	12.3 6.6–22.8ROR 12.4 · χ² 93 / p 3e-22	10.2 EB05 5.2 · IC025 +1.9 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious n=9	no trial data cached
Muscle spasticity	8	11.2 5.6–22.3ROR 11.3 · χ² 64 / p 5e-16	8.5 EB05 4.1 · IC025 +1.6 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 14.0	no trial data cached
Body height decreased	6	9.6 4.3–21.4ROR 9.7 · χ² 38 / p 3e-10	6.5 EB05 3.0 · IC025 +1.1 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious n=4	no trial data cached
Gastrointestinal carcinoma	5	9.4 3.9–22.7ROR 9.5 · χ² 30 / p 2e-8	6.0 EB05 2.6 · IC025 +0.9 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 9.5	no trial data cached
Urosepsis	5	9.4 3.9–22.6ROR 9.4 · χ² 30 / p 3e-8	6.0 EB05 2.6 · IC025 +0.9 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 9.5	no trial data cached
Hallucination, visual	11	9.1 5.0–16.4ROR 9.2 · χ² 71 / p 2e-17	7.3 EB05 4.1 · IC025 +1.7 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 9.5	no trial data cached
Product use complaint	8	8.9 4.5–17.9ROR 9.0 · χ² 49 / p 1e-12	6.6 EB05 3.4 · IC025 +1.4 3/3 methods agree	Reporting / coding artifact	serious n=4	no trial data cached
Vitreous floaters	5	8.9 3.7–21.4ROR 8.9 · χ² 28 / p 7e-8	5.7 EB05 2.5 · IC025 +0.8 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious n=4	no trial data cached
Bladder disorder	5	8.7 3.6–20.9ROR 8.7 · χ² 27 / p 1e-7	5.6 EB05 2.4 · IC025 +0.8 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious n=2	no trial data cached
Wrist fracture	6	8.7 3.9–19.3ROR 8.7 · χ² 33 / p 4e-9	5.9 EB05 2.8 · IC025 +1.0 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 10.2	no trial data cached
Delusion	7	7.8 3.7–16.4ROR 7.9 · χ² 35 / p 1e-9	5.6 EB05 2.8 · IC025 +1.1 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 1.4	no trial data cached
Localised infection	10	7.2 3.9–13.3ROR 7.2 · χ² 47 / p 3e-12	5.6 EB05 3.2 · IC025 +1.4 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 8.4	no trial data cached
Eye irritation	17	5.3 3.3–8.5ROR 5.3 · χ² 55 / p 6e-14	4.7 EB05 3.1 · IC025 +1.4 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 3.1	no trial data cached
Product physical issue	6	5.2 2.3–11.6ROR 5.2 · χ² 16 / p 2e-5	3.9 EB05 2.0 · IC025 +0.6	Reporting / coding artifact	–	no trial data cached
Multiple sclerosis relapse	17	4.3 2.7–6.8ROR 4.3 · χ² 39 / p 2e-10	3.9 EB05 2.6 · IC025 +1.1 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 4.6	no trial data cached
Multiple sclerosis	10	3.6 1.9–6.7ROR 3.6 · χ² 16 / p 3e-5	3.2 EB05 1.9 · IC025 +0.6	No label text to screen label has no adverse-reaction text	serious PRR 4.3	no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Urinary tract infection (bladder infection)	163	16.6 14.4–19.2ROR 19.1 · χ² 2,395 / p <1e-300	16.6 EB05 14.5 · IC025 +3.7 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 17.3	no trial data cached
Cystitis	29	15.7 11.0–22.5ROR 16.1 · χ² 386 / p 3e-86	15.4 EB05 11.1 · IC025 +3.0 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 18.6	no trial data cached
Multiple sclerosis relapse	17	4.3 2.7–6.8ROR 4.3 · χ² 39 / p 2e-10	3.9 EB05 2.6 · IC025 +1.1 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 4.6	no trial data cached
Eye irritation	17	5.3 3.3–8.5ROR 5.3 · χ² 55 / p 6e-14	4.7 EB05 3.1 · IC025 +1.4 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 3.1	no trial data cached
Kidney infection	17	15.0 9.4–24.1ROR 15.2 · χ² 209 / p 1e-47	14.3 EB05 8.9 · IC025 +2.6 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 16.9	no trial data cached
Product taste abnormal	17	21.9 13.7–35.2ROR 22.2 · χ² 319 / p 1e-71	21.4 EB05 14.0 · IC025 +3.0 3/3 methods agree	Reporting / coding artifact	serious n=2	no trial data cached
Hallucination, visual	11	9.1 5.0–16.4ROR 9.2 · χ² 71 / p 2e-17	7.3 EB05 4.1 · IC025 +1.7 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 9.5	no trial data cached
Multiple sclerosis	10	3.6 1.9–6.7ROR 3.6 · χ² 16 / p 3e-5	3.2 EB05 1.9 · IC025 +0.6	No label text to screen label has no adverse-reaction text	serious PRR 4.3	no trial data cached
Localised infection	10	7.2 3.9–13.3ROR 7.2 · χ² 47 / p 3e-12	5.6 EB05 3.2 · IC025 +1.4 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 8.4	no trial data cached
Seasonal allergy	10	12.3 6.6–22.8ROR 12.4 · χ² 93 / p 3e-22	10.2 EB05 5.2 · IC025 +1.9 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious n=9	no trial data cached
Product use complaint	8	8.9 4.5–17.9ROR 9.0 · χ² 49 / p 1e-12	6.6 EB05 3.4 · IC025 +1.4 3/3 methods agree	Reporting / coding artifact	serious n=4	no trial data cached
Muscle spasticity	8	11.2 5.6–22.3ROR 11.3 · χ² 64 / p 5e-16	8.5 EB05 4.1 · IC025 +1.6 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 14.0	no trial data cached
Delusion	7	7.8 3.7–16.4ROR 7.9 · χ² 35 / p 1e-9	5.6 EB05 2.8 · IC025 +1.1 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 1.4	no trial data cached
Product physical issue	6	5.2 2.3–11.6ROR 5.2 · χ² 16 / p 2e-5	3.9 EB05 2.0 · IC025 +0.6	Reporting / coding artifact	–	no trial data cached
Wrist fracture	6	8.7 3.9–19.3ROR 8.7 · χ² 33 / p 4e-9	5.9 EB05 2.8 · IC025 +1.0 3/3 methods agree	No label text to screen label has no adverse-reaction text	serious PRR 10.2	no trial data cached

Unlabeled candidate signals

Every screened signal with n ≥ 20 was either labeled, an indication term, or an artifact pattern — no unlabeled candidate stood out in the top signals.

Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.

Common questions

What are the most reported side effects of Methenamine Hippurate?

In FDA FAERS, the most frequently co-reported reaction terms for Methenamine Hippurate are urinary tract infection, cystitis, multiple sclerosis relapse, eye irritation, kidney infection, hallucination, visual. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.

Does Methenamine Hippurate have an FDA boxed warning?

No. The FDA label retrieved for Methenamine Hippurate has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Methenamine Hippurate causes these side effects?

No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.

Sources & methods

FDA label via openFDA (set ID 4263d826-7de2-4011-b8ec-ba1f5222f0e6, effective 20260203; matched on openfda.generic_name.exact:"METHENAMINE HIPPURATE" AND openfda.product_type:"HUMAN PRESCRIPTION DRUG")
Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA count= aggregation, field patient.drug.openfda.generic_name.exact, 28 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction
Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
Seriousness and sex counts from openFDA count=serious, patient.patientsex, seriousnessdeath

Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.