Drug · FAERS side-effect profile with label screen
Metronidazole Topical side effects: what 47,359 FDA adverse event reports show
Drug class
FDA label (Established Pharmacologic Class) · compare the class
Brand names
Metronidazole
openFDA label
Who reports
47,359 reports · 87% serious · 5,345 with death outcome · 61% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Metronidazole gel USP (topical), 0.75%, is indicated for topical application in the treatment of inflammatory papules and pustules of rosacea.
FDA label, Indications and Usage
What it is
DESCRIPTION Metronidazole gel USP (topical), 0.75%, contains metronidazole, at a concentration of 7.5 mg per gram (0.75%) in a gel consisting of carbopol 980, edetate disodium, methylparaben, propylene glycol, propylparaben, purified water, and sodium hydroxide.
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 40 strongest signals
Reporting / coding artifact 6Lab value / disease marker 2No label text to screen 32
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.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- 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, for the 300 most-reported drugs, adjusted for age band), and flags pairs whose reports are unusually skewed by sex or come mostly from consumers. Each row also shows the PRR against the other drugs of the same FDA class, which removes most confounding by the condition being treated, and a calibrated p-value: on validation, known non-causes average an ROR of about 2, so significance is judged against that empirical null (✓ = p < 0.05 after calibration). 1,207 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
Show:
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Vaginal flatulence | 245 | 1,873.3 1,404.4–2,498.7ROR 1,883.0 · calibrated p 5e-20 ✓ | 344.8 EB05 310.1 · IC025 +7.5 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.4 (3.7–5.3) | No label text to screen label has no adverse-reaction text | serious n=245 · ♀ 100% (drug 61%) | not reported in cached trials |
| Appendicolith | 284 | 1,360.1 1,074.3–1,722.1ROR 1,368.3 · calibrated p 2e-18 ✓ | 323.6 EB05 293.2 · IC025 +7.5 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.5 (3.8–5.3) | No label text to screen label has no adverse-reaction text | serious n=284 · ♀ 0% (drug 61%) · 96% clinician | not reported in cached trials |
| Sleep disorder therapy | 127 | 971.0 710.5–1,327.1ROR 973.6 · calibrated p 2e-16 ✓ | 288.4 EB05 248.7 · IC025 +6.8 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.5 (3.5–5.8) | Reporting / coding artifact | serious n=127 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Antacid therapy | 79 | 860.7 588.5–1,259.0ROR 862.2 · calibrated p 1e-15 ✓ | 271.0 EB05 224.4 · IC025 +6.3 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.5 (3.3–6.1) | Reporting / coding artifact | serious n=79 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Analgesic therapy | 120 | 285.8 227.1–359.7ROR 286.5 · calibrated p 3e-11 ✓ | 168.4 EB05 144.6 · IC025 +6.4 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.5 (3.5–5.8) | Reporting / coding artifact | serious n=120 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Drug therapy | 108 | 226.3 179.4–285.5ROR 226.8 · calibrated p 2e-10 ✓ | 145.5 EB05 123.9 · IC025 +6.2 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.5 (3.5–5.9) | Reporting / coding artifact | serious n=108 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Anticoagulant therapy | 78 | 173.4 133.4–225.4ROR 173.7 · calibrated p 2e-9 ✓ | 120.7 EB05 99.9 · IC025 +5.7 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.5 (3.3–6.2) | Reporting / coding artifact | serious n=78 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Malignant melanoma stage 0 | 44 | 142.0 101.1–199.6ROR 142.2 · calibrated p 2e-8 ✓ | 102.7 EB05 79.7 · IC025 +5.1 3/3 methods agree vs other Nitroimidazole Antimicrobials: only this drug | No label text to screen label has no adverse-reaction text | serious n=44 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Congenital hiatus hernia | 51 | 132.3 96.7–181.0ROR 132.4 · calibrated p 3e-8 ✓ | 98.1 EB05 77.5 · IC025 +5.2 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.5 (3.1–6.6) | No label text to screen label has no adverse-reaction text | serious n=51 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Bacteroides infection | 46 | 95.5 69.4–131.3ROR 95.6 · calibrated p 3e-7 ✓ | 76.1 EB05 59.4 · IC025 +4.9 3/3 methods agree vs other Nitroimidazole Antimicrobials: only this drug | No label text to screen label has no adverse-reaction text | serious n=46 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Female genital tract fistula | 280 | 86.0 75.7–97.7ROR 86.5 · calibrated p 4e-7 ✓ | 71.7 EB05 64.9 · IC025 +5.8 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.9 (3.3–4.6) | No label text to screen label has no adverse-reaction text | serious n=280 · ♀ 100% (drug 61%) | not reported in cached trials |
| Toxic encephalopathy | 631 | 64.8 59.7–70.5ROR 65.7 · calibrated p 2e-6 ✓ | 56.5 EB05 52.9 · IC025 +5.6 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.3 (3.9–4.8) | No label text to screen label has no adverse-reaction text | serious n=630 · ♀ 38% (drug 61%) · 100% clinician | not reported in cached trials |
| Dysmetria | 62 | 50.7 39.0–65.9ROR 50.8 · calibrated p 2e-5 ✓ | 44.9 EB05 36.3 · IC025 +4.6 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.9 (2.8–5.5) | No label text to screen label has no adverse-reaction text | serious n=62 · 100% clinician | not reported in cached trials |
| Proctitis | 279 | 48.9 43.2–55.3ROR 49.1 · calibrated p 2e-5 ✓ | 43.9 EB05 39.7 · IC025 +5.2 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.2 (3.6–4.9) | No label text to screen label has no adverse-reaction text | serious n=279 · ♀ 94% (drug 61%) | not reported in cached trials |
| Radiculopathy | 262 | 48.8 42.9–55.4ROR 49.0 · calibrated p 2e-5 ✓ | 43.8 EB05 39.6 · IC025 +5.1 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.1 (3.5–4.9) | No label text to screen label has no adverse-reaction text | serious n=262 · ♀ 100% (drug 61%) | not reported in cached trials |
| Cerebellar ataxia | 90 | 45.6 36.7–56.7ROR 45.7 · calibrated p 3e-5 ✓ | 41.1 EB05 34.4 · IC025 +4.7 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.9 (3.0–5.2) | No label text to screen label has no adverse-reaction text | serious n=88 · ♀ 30% (drug 61%) · 100% clinician | not reported in cached trials |
| Bloody discharge | 103 | 43.5 35.5–53.2ROR 43.5 · calibrated p 4e-5 ✓ | 39.3 EB05 33.4 · IC025 +4.7 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.1 (3.1–5.3) | No label text to screen label has no adverse-reaction text | serious n=103 · ♀ 100% (drug 61%) · 90% clinician | not reported in cached trials |
| Pancreatitis haemorrhagic | 41 | 42.5 30.9–58.6ROR 42.6 · calibrated p 6e-5 ✓ | 38.2 EB05 29.4 · IC025 +4.2 3/3 methods agree vs other Nitroimidazole Antimicrobials: only this drug | No label text to screen label has no adverse-reaction text | serious n=41 · ♀ 100% (drug 61%) · 100% clinician | not reported in cached trials |
| Cerebellar syndrome | 193 | 42.3 36.5–49.0ROR 42.4 · calibrated p 4e-5 ✓ | 38.5 EB05 34.1 · IC025 +4.9 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.0 (3.3–4.8) | No label text to screen label has no adverse-reaction text | serious n=192 · 100% clinician | not reported in cached trials |
| Pseudomembranous colitis | 183 | 39.2 33.7–45.6ROR 39.4 · calibrated p 6e-5 ✓ | 36.0 EB05 31.8 · IC025 +4.8 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.4 (2.8–4.1) | No label text to screen label has no adverse-reaction text | serious n=183 · 100% clinician | not reported in cached trials |
| Chronic sinusitis | 292 | 37.4 33.2–42.1ROR 37.6 · calibrated p 8e-5 ✓ | 34.4 EB05 31.2 · IC025 +4.8 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.2 (3.6–4.9) | No label text to screen label has no adverse-reaction text | serious n=291 · ♀ 100% (drug 61%) | NCT01426269: 4/235 (1.7%) on Metronidazole Topical; 2/65 (3.1%) control |
| Hyperphosphataemia | 165 | 37.3 31.8–43.7ROR 37.4 · calibrated p 8e-5 ✓ | 34.3 EB05 30.2 · IC025 +4.7 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.3 (3.5–5.4) | No label text to screen label has no adverse-reaction text | serious n=164 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Reversible airways obstruction | 37 | 34.2 24.5–47.8ROR 34.3 · calibrated p 2e-4 ✓ | 31.4 EB05 23.8 · IC025 +3.9 3/3 methods agree vs other Nitroimidazole Antimicrobials: only this drug | No label text to screen label has no adverse-reaction text | serious n=38 · ♀ 0% (drug 61%) · 100% consumer | not reported in cached trials |
| Macular degeneration | 853 | 34.1 31.8–36.5ROR 34.7 · calibrated p 1e-4 ✓ | 31.7 EB05 29.9 · IC025 +4.8 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.5 (4.1–4.9) | No label text to screen label has no adverse-reaction text | serious PRR 22.6 · ♀ 100% (drug 61%) | not reported in cached trials |
| Megacolon | 110 | 33.4 27.5–40.5ROR 33.5 · calibrated p 2e-4 ✓ | 31.0 EB05 26.4 · IC025 +4.5 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.1 (3.2–5.3) | No label text to screen label has no adverse-reaction text | serious n=110 · ♀ 25% (drug 61%) · 100% clinician | not reported in cached trials |
| International normalised ratio fluctuation | 146 | 33.1 28.0–39.1ROR 33.2 · calibrated p 2e-4 ✓ | 30.7 EB05 26.8 · IC025 +4.5 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.0 (3.2–5.0) | Lab value / disease marker | serious n=145 · ♀ 100% (drug 61%) · 94% clinician | not reported in cached trials |
| Blood phosphorus increased | 188 | 32.7 28.2–38.0ROR 32.9 · calibrated p 2e-4 ✓ | 30.4 EB05 27.0 · IC025 +4.6 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.3 (3.6–5.3) | Lab value / disease marker | serious n=188 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Bronchopulmonary aspergillosis allergic | 62 | 32.1 24.8–41.5ROR 32.1 · calibrated p 2e-4 ✓ | 29.7 EB05 24.0 · IC025 +4.2 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.5 (3.2–6.4) | No label text to screen label has no adverse-reaction text | serious n=62 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Abortion incomplete | 122 | 30.5 25.4–36.7ROR 30.6 · calibrated p 3e-4 ✓ | 28.5 EB05 24.5 · IC025 +4.4 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.9 (3.1–5.0) | No label text to screen label has no adverse-reaction text | ♀ 100% (drug 61%) · 100% clinician | not reported in cached trials |
| Pouchitis | 53 | 28.9 21.9–38.2ROR 29.0 · calibrated p 4e-4 ✓ | 27.0 EB05 21.4 · IC025 +4.0 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 2.7 (1.9–3.8) | No label text to screen label has no adverse-reaction text | serious n=53 · ♀ 40% (drug 61%) · 100% clinician | not reported in cached trials |
| Dysbiosis | 48 | 28.2 21.0–37.7ROR 28.2 · calibrated p 5e-4 ✓ | 26.3 EB05 20.6 · IC025 +3.9 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.2 (2.9–6.3) | No label text to screen label has no adverse-reaction text | serious n=48 · ♀ 100% (drug 61%) · 100% clinician | not reported in cached trials |
| Chronic kidney disease-mineral and bone disorder | 60 | 26.1 20.1–33.9ROR 26.1 · calibrated p 7e-4 ✓ | 24.5 EB05 19.7 · IC025 +3.9 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.0 (2.8–5.6) | No label text to screen label has no adverse-reaction text | serious n=60 | not reported in cached trials |
| Clostridium difficile colitis | 584 | 25.7 23.7–27.9ROR 26.0 · calibrated p 6e-4 ✓ | 24.3 EB05 22.7 · IC025 +4.4 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.2 (2.9–3.6) | No label text to screen label has no adverse-reaction text | serious PRR 16.3 · 92% clinician | not reported in cached trials |
| Pathogen resistance | 486 | 24.9 22.8–27.3ROR 25.2 · calibrated p 7e-4 ✓ | 23.6 EB05 21.9 · IC025 +4.4 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.4 (3.9–5.0) | Reporting / coding artifact | serious PRR 16.3 · ♀ 27% (drug 61%) · 100% clinician | not reported in cached trials |
| Linear iga disease | 84 | 23.5 18.9–29.2ROR 23.5 · calibrated p 0.001 ✓ | 22.2 EB05 18.5 · IC025 +3.9 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.3 (3.2–5.8) | No label text to screen label has no adverse-reaction text | serious n=84 · 100% clinician | not reported in cached trials |
| Fixed eruption | 85 | 23.3 18.8–29.0ROR 23.4 · calibrated p 0.001 ✓ | 22.1 EB05 18.4 · IC025 +3.9 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.5 (3.3–6.0) | No label text to screen label has no adverse-reaction text | serious n=72 · 100% clinician | not reported in cached trials |
| Fistula discharge | 61 | 22.3 17.2–28.8ROR 22.3 · calibrated p 0.001 ✓ | 21.1 EB05 17.0 · IC025 +3.8 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 2.5 (1.8–3.4) | No label text to screen label has no adverse-reaction text | serious n=60 · ♀ 0% (drug 61%) | not reported in cached trials |
| Acinetobacter infection | 51 | 21.8 16.5–28.9ROR 21.9 · calibrated p 0.002 ✓ | 20.7 EB05 16.3 · IC025 +3.7 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.2 (2.9–6.1) | No label text to screen label has no adverse-reaction text | serious n=51 · 100% clinician | not reported in cached trials |
| Total lung capacity decreased | 74 | 21.4 16.9–27.0ROR 21.4 · calibrated p 0.002 ✓ | 20.4 EB05 16.7 · IC025 +3.8 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.4 (3.2–6.0) | No label text to screen label has no adverse-reaction text | serious n=74 · ♀ 0% (drug 61%) · 100% clinician | not reported in cached trials |
| Hyperparathyroidism secondary | 114 | 20.8 17.3–25.1ROR 20.9 · calibrated p 0.002 ✓ | 19.9 EB05 17.0 · IC025 +3.9 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 4.0 (3.1–5.2) | No label text to screen label has no adverse-reaction text | serious n=114 | not reported in cached trials |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Metronidazole Topical as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (1 of 40 signal terms matched).
- NCT01426269 — Evaluation of Relapse, Efficacy and Safety of Long-term Treatment With Oracea® vs Placebo (N=235, PHASE4; 15 AE terms posted; arms: Period 1: Oral Doxycycline and Topical M; Period 2: Oral Doxycycline; Period 2: Placebo)
- NCT01230814 — Topical Metronidazole and Miconazole Co-formulated Vaginal Suppositories for Preventing Vaginal Infections in (N=234, PHASE2; 35 AE terms posted; arms: Arm 1: Metronidazole Plus Miconazole; Arm 2: Placebo)
Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.
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 |
|---|---|---|---|---|---|---|
| Drug ineffective (drug did not work) | 4,555 | 1.5 1.5–1.6ROR 1.6 · calibrated p 0.700 | 1.5 EB05 1.5 · IC025 +0.6 vs other Nitroimidazole Antimicrobials: PRR 3.8 (3.6–3.9) | Reporting / coding artifact | serious PRR 2.5 | not reported in cached trials |
| Nausea | 3,422 | 1.9 1.9–2.0ROR 2.0 · calibrated p 0.942 | 1.9 EB05 1.9 · IC025 +0.9 vs other Nitroimidazole Antimicrobials: PRR 3.3 (3.2–3.4) | No label text to screen label has no adverse-reaction text | serious PRR 2.2 | NCT01426269: 2/235 (0.9%) on Metronidazole Topical |
| Off label use (used outside approved label) | 3,311 | 1.7 1.6–1.7ROR 1.7 · calibrated p 0.796 | 1.7 EB05 1.6 · IC025 +0.7 vs other Nitroimidazole Antimicrobials: PRR 3.6 (3.4–3.8) | Reporting / coding artifact | serious PRR 1.9 | not reported in cached trials |
| Diarrhoea (diarrhea) | 2,684 | 1.9 1.8–1.9ROR 1.9 · calibrated p 0.889 | 1.8 EB05 1.8 · IC025 +0.8 vs other Nitroimidazole Antimicrobials: PRR 3.0 (2.8–3.1) | No label text to screen label has no adverse-reaction text | serious PRR 1.9 | not reported in cached trials |
| Vomiting | 2,300 | 2.2 2.1–2.3ROR 2.2 · calibrated p 0.933 | 2.2 EB05 2.1 · IC025 +1.0 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.1 (3.0–3.3) | No label text to screen label has no adverse-reaction text | serious PRR 2.0 | not reported in cached trials |
| Pyrexia (fever) | 2,260 | 2.9 2.8–3.0ROR 3.0 · calibrated p 0.627 | 2.9 EB05 2.8 · IC025 +1.5 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.1 (3.0–3.3) | No label text to screen label has no adverse-reaction text | serious PRR 2.3 | not reported in cached trials |
| Headache | 2,213 | 1.6 1.5–1.6ROR 1.6 · calibrated p 0.703 | 1.6 EB05 1.5 · IC025 +0.6 vs other Nitroimidazole Antimicrobials: PRR 3.5 (3.3–3.7) | No label text to screen label has no adverse-reaction text | serious PRR 1.9 | NCT01426269: 1/235 (0.4%) on Metronidazole Topical (serious AE) |
| Pain | 2,096 | 1.5 1.4–1.6ROR 1.5 · calibrated p 0.663 | 1.5 EB05 1.5 · IC025 +0.5 vs other Nitroimidazole Antimicrobials: PRR 3.1 (2.9–3.3) | No label text to screen label has no adverse-reaction text | serious PRR 1.4 | NCT01426269: 1/235 (0.4%) on Metronidazole Topical (serious AE) |
| Abdominal pain | 2,089 | 4.0 3.8–4.2ROR 4.1 · calibrated p 0.352 | 4.0 EB05 3.8 · IC025 +1.9 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.1 (3.0–3.3) | No label text to screen label has no adverse-reaction text | serious PRR 3.4 | NCT01230814: 8/116 (6.9%) on Metronidazole Topical; 17/116 (14.7%) control |
| Fatigue (tiredness) | 1,923 | 1.1 1.0–1.1ROR 1.1 · calibrated p 0.373 | 1.1 EB05 1.1 · IC025 +0.1 vs other Nitroimidazole Antimicrobials: PRR 3.1 (2.9–3.2) | No label text to screen label has no adverse-reaction text | serious PRR 1.2 | not reported in cached trials |
| Dizziness | 1,664 | 1.5 1.4–1.6ROR 1.5 · calibrated p 0.641 | 1.5 EB05 1.4 · IC025 +0.5 vs other Nitroimidazole Antimicrobials: PRR 3.4 (3.2–3.7) | No label text to screen label has no adverse-reaction text | serious PRR 1.5 | not reported in cached trials |
| Condition aggravated | 1,594 | 2.3 2.2–2.5ROR 2.4 · calibrated p 0.861 | 2.3 EB05 2.2 · IC025 +1.1 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.4 (3.2–3.6) | Reporting / coding artifact | serious PRR 2.2 | not reported in cached trials |
| Dyspnoea (shortness of breath) | 1,566 | 1.2 1.2–1.3ROR 1.2 · calibrated p 0.463 | 1.2 EB05 1.2 · IC025 +0.2 vs other Nitroimidazole Antimicrobials: PRR 3.2 (3.0–3.4) | No label text to screen label has no adverse-reaction text | serious PRR 1.1 | not reported in cached trials |
| Acute kidney injury (sudden kidney damage) | 1,532 | 4.5 4.3–4.7ROR 4.6 · calibrated p 0.282 | 4.4 EB05 4.3 · IC025 +2.1 3/3 methods agree vs other Nitroimidazole Antimicrobials: PRR 3.7 (3.5–4.0) | No label text to screen label has no adverse-reaction text | serious PRR 2.9 | not reported in cached trials |
| Malaise (feeling unwell) | 1,458 | 1.5 1.4–1.5ROR 1.5 · calibrated p 0.632 | 1.5 EB05 1.4 · IC025 +0.5 vs other Nitroimidazole Antimicrobials: PRR 3.3 (3.1–3.5) | No label text to screen label has no adverse-reaction text | serious PRR 1.5 | not reported in cached trials |
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.
✓ A hand-written Bradford Hill causality assessment exists for this drug: Metronidazole ↔ Peripheral neuropathy.
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 Metronidazole Topical?
In FDA FAERS, the most frequently co-reported reaction terms for Metronidazole Topical are nausea, diarrhoea, vomiting, pyrexia, headache, pain. 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 Metronidazole Topical have an FDA boxed warning?
No. The FDA label retrieved for Metronidazole Topical has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Metronidazole Topical 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 05707735-e676-412a-9a77-ebd003afb16c, effective 20250912; matched on
openfda.generic_name.exact:"METRONIDAZOLE TOPICAL" 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, fieldpatient.drug.openfda.generic_name.exact, 1,247 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 - ClinicalTrials.gov API v2 (query
METRONIDAZOLE TOPICAL, results-bearing studies sorted by enrollment)
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