Reported Reactions

Drugs › Nitroimidazole antimicrobial

Brand name · Bismuth subcitrate potassium, metronidazole, and tetracycline hydrochloride

Pylera: adverse event reports filed with FDA

992 reports list it as a suspect or interacting product, 2008–2026. Class: Nitroimidazole antimicrobial. Also reported as Pylera Capsule.

992
reports as suspect product
0% of all reports · about 54 a year
91
reports, 12 months to June 2026
66 in the 12 months before
83.5%
marked serious by the reporter
84.2% across the class
1.6%
record death among outcomes, as reported
16 reports · not verified by FDA

992 adverse event reports received by FDA list the brand name Pylera (bismuth subcitrate potassium, metronidazole, and tetracycline hydrochloride) as a suspect or interacting product, from March 2008 to June 2026. A further 130 reports list it only as a concomitant medication, and those are not counted in the figures on this page.

In the 12 months to June 2026, 91 reports listed it, up 38% from 66 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 54 reports a year and 0% of the 20,646,523 reports in the database, and 3.1% of the reports for the nitroimidazole antimicrobial class. How many people take it is not in the data, so a count is not a rate of occurrence.

The reactions recorded most often are nausea (11.8%), headache (10.8%) and diarrhoea (9.3%). A report can list several reactions, so shares add to more than 100%; 286 different terms appear across these reports. Nausea is recorded in 11.8% of these reports, a larger share than in the median nitroimidazole antimicrobial drug (8.6%).

83.5% of the reports are marked serious by the reporter (84.2% across the class); 1.6% record death among the outcomes and 36.5% record hospitalisation, as reported. 32.1% of the reports came from physicians, and the largest patient age group is 45 to 64 (28.7%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

01019Jul 2021: 4Aug 2021: 9Sep 2021: 6Oct 2021: 1Nov 2021: 19Dec 2021: 22022Jan 2022: 1Feb 2022: 3Mar 2022: 4Apr 2022: 11May 2022: 3Jun 2022: 12Jul 2022: 6Aug 2022: 4Sep 2022: 7Oct 2022: 3Nov 2022: 7Dec 2022: 72023Jan 2023: 5Feb 2023: 4Mar 2023: 6Apr 2023: 7May 2023: 3Jun 2023: 8Jul 2023: 4Aug 2023: 0Sep 2023: 4Oct 2023: 0Nov 2023: 4Dec 2023: 62024Jan 2024: 7Feb 2024: 6Mar 2024: 7Apr 2024: 4May 2024: 10Jun 2024: 7Jul 2024: 6Aug 2024: 5Sep 2024: 7Oct 2024: 1Nov 2024: 3Dec 2024: 52025Jan 2025: 3Feb 2025: 3Mar 2025: 6Apr 2025: 11May 2025: 2Jun 2025: 14Jul 2025: 3Aug 2025: 6Sep 2025: 7Oct 2025: 10Nov 2025: 6Dec 2025: 142026Jan 2026: 5Feb 2026: 7Mar 2026: 8Apr 2026: 13May 2026: 8Jun 2026: 4

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

048952008: 1120082009: 182010: 220102011: 22012: 220122013: 362014: 4720142015: 672016: 6720162017: 732018: 9520182019: 822020: 9120202021: 822022: 6820222023: 512024: 6820242025: 852026: 452026

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Pylera reports recording the termmedian drug in nitroimidazole antimicrobial

  1. Nauseafeeling sick11.8%117
  2. Headachehead pain10.8%107
  3. Diarrhoealoose or frequent stools9.3%92
  4. Dizzinesslight-headedness or unsteadiness7.6%75
  5. Astheniaweakness or lack of energy7%69
  6. Vomitingbeing sick6.8%67
  7. Off label useused for a purpose or in a way not on the label5.5%55
  8. Pruritusitching5.4%54
  9. Abdominal pain upperupper stomach pain5.3%53
  10. Fatiguetiredness4.7%47
  11. Pyrexiafever4.6%46
  12. Dyspnoeashortness of breath4.5%45
  13. Abdominal painstomach or belly pain4.3%43
  14. Paraesthesiatingling or pins and needles4.3%43
  15. Vertigoa spinning sensation3.8%38
  16. Decreased appetitereduced appetite3.6%36
  17. Malaisegeneral feeling of being unwell3.4%34
  18. Anxietyanxiety3.3%33
  19. Dysgeusiaaltered taste3.2%32
  20. Myalgiamuscle pain3%30
  21. Angioedemadeep swelling of skin or mucous membranes2.9%29
  22. Rashskin rash2.7%27
  23. Painpain, site not specified2.6%26
  24. Somnolencedrowsiness2.6%26
  25. Palpitationsawareness of the heartbeat2.5%25
  26. Erythemaskin redness2.3%23
  27. Depressionlow mood2.2%22
  28. Tremorshaking2.2%22

Top 30 of 286 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 3 drugs in the nitroimidazole antimicrobial class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Outcomes recorded

Death1.6%16
Life-threatening3.5%35
Hospitalisation (initial or prolonged)36.5%362
Disability5.3%53
Congenital anomaly0.3%3
Other serious49.7%493
Not serious16.5%164

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 32,128 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Patient age

Under 20.1%1
2 to 110%0
12 to 170.4%4
18 to 4423.6%234
45 to 6428.7%285
65 to 7410.1%100
75 and over7.6%75
Age not given29.5%293

Patient sex

Female59.6%591
Male35%347
Not given5.4%54

Who reported

Physician32.1%318
Pharmacist8.7%86
Other health professional18.2%181
Lawyer0%0
Consumer or non-health professional30.9%307
Not given10.1%100

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 20.8% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Helicobacter infection57057.5%
Helicobacter gastritis13813.9%
Gastritis161.6%
Gastric ulcer helicobacter121.2%
Helicobacter test positive101%
Peptic ulcer70.7%

The indication field is filled in by the reporter and is often blank; shares are of all 992 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Pylera reports
Omeprazole27127.3%
Esomeprazole798%
Pantoprazole717.2%
Amlodipine191.9%
Atorvastatin171.7%
Pantoprazole sodium161.6%
Amoxicillin151.5%
Metformin151.5%
Metformine151.5%
Humalog141.4%

Other products listed in reports where Pylera is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.

In context

MeasurePyleraNitroimidazole antimicrobialAll reports
Reports as suspect product99232,12820,646,523
Share of that pool—3.1%0%
Reports, latest 12 months91—1,332,454
Marked serious83.5%84.2%57.4%
Death recorded among outcomes, per 1,000 reports168991
Hospitalisation recorded, per 1,000 reports365373213
Consumer-filed share30.9%20.6%45.8%
Top term, share of reportsNausea 11.8%median 8.6%3.8%

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Other drugs in the nitroimidazole antimicrobial class

DrugName typeReportsLatest 12 monthsMarked serious
Metronidazolegeneric24,3321,69490.1%
Flagylbrand6,80411263.1%

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.

Questions about Pylera reports

How many adverse event reports has FDA received for Pylera?

992 reports list Pylera as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 91 of them arrived in the latest 12 months. Another 130 list it only as a concomitant medication.

What reactions are recorded in Pylera reports?

nausea (11.8%), headache (10.8%), diarrhoea (9.3%), faeces discoloured (7.7%) and dizziness (7.6%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Pylera was responsible.

How serious are the reports?

83.5% are marked serious by the reporter. Among the outcomes recorded, 1.6% of reports include death and 36.5% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.

Who files these reports?

physician (32.1%), consumer or non-health professional (30.9%) and other health professional (18.2%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Pylera rising?

91 reports in the 12 months to June 2026, up 38% from 66 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.

Do these reports show that Pylera was responsible for these reactions?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.

Is this a list of the side effects of Pylera?

No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.

How do I report an adverse event?

Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Pylera as a suspect or interacting product; reports listing it only as a concomitant medication (130) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.