Reported Reactions

Adverse event reports that FDA received

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Biguanide adverse event reports that FDA received for the drugs of this class

Kind of class
Pharmacologic class (FDA Established Pharmacologic Class)
Drug pages
7

What a report is

A report is not proof that the drug was the cause of the event.

FDA says:

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.

Source: openFDA, Drug Adverse Event Overview, section "Responsible use of the data". The site read the page on . The data have the reports that FDA received through .

FDA also says:

There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event. The information in these reports has not been scientifically or otherwise verified as to a cause and effect relationship and cannot be used to estimate the incidence of these events.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Source: openFDA, Response of the drug event API (meta.disclaimer). The site read the page on .

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

Reports on file

Biguanide is a pharmacologic class: an FDA Established Pharmacologic Class. The class has 7 drug pages on this site.

From January 2004 to June 2026, FDA received 116,598 adverse event reports that name a drug of the class. In these reports the drug is a suspect or interacting product. A report that names two drugs of the class counts one time for each.

FDA received 7,340 reports in the 12 months to June 2026 and 7,269 in the 12 months before. FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.

Of the 1,332,454 drug reports that FDA received in the 12 months to June 2026, 7,340 (0.6%) name a drug of the class. Reports from consumers or other non-health professionals were 28.4% of the reports that name a drug of the class and 45.8% of all drug reports.

The number of people who use the product is not in the data. A count is not a rate.

Pharmacologic class

The Established Pharmacologic Class (EPC) of FDA is the class on the label of a drug. The site puts a drug in the class that its reports have most often.

Data version

openFDA FAERS release of 29 Oct 2026. Reports received through 30 Jun 2026.

Drugs of the class

The rows are in order of name. A brand name and its generic name are separate rows, because reporters name them separately.

FDA says:

Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.

Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of . The site read the page on .

Drug pages of the class Biguanide, in order of name
DrugName typeReportsReports, 12 months to June 2026
Actoplus MetPioglitazone and metformin hydrochlorideBrand name5580
InvokametCanagliflozin and metformin hydrochlorideBrand name1,3361
JanumetSitagliptin and metformin hydrochlorideBrand name10,509133
MetforminGeneric name66,4955,178
Metformin hclGeneric name11,3140
Metformin hydrochlorideGeneric name24,1871,851
XigduoDapagliflozin and metformin hydrochlorideBrand name2,199177

Reaction lookup

These are the reaction terms that the reports of the class record. Type a term or a plain word to find its count.

What this list leaves out

The table lists the 2,970 reaction terms that 5 or more reports record. A term with fewer than 5 reports is not in the table.

The site keeps reaction terms for 116,218 of the 116,598 reports (99.7%).

The reports of the other years are not in the counts.

So a count in the table can be lower than the count of FDA.

The table shows the first 50 of 2,970 terms.

Reaction terms in the reports that name a biguanide drug, most reports first
Reaction term (MedDRA) and plain meaningReportsShare of the 116,598 reports
Lactic acidosisa build-up of lactic acid in the blood19,73016.9%
Acute kidney injurysudden loss of kidney function11,62810%
Diarrhoealoose or frequent stools9,6538.3%
Toxicity to various agentspoisoning or toxic effect of one or more substances6,6745.7%
Nauseafeeling sick6,4425.5%
Hypoglycaemialow blood sugar6,2255.3%
Vomitingbeing sick6,1535.3%
Metabolic acidosistoo much acid in the body fluids6,1375.3%
Blood glucose increasedraised blood sugar reading6,1235.3%
Drug ineffectivethe medicine did not work as expected6,1165.2%
Hypotensionlow blood pressure4,0403.5%
Completed suicidedeath by suicide3,8593.3%
Dyspnoeashortness of breath3,6673.1%
Fatiguetiredness3,6403.1%
Malaisegeneral feeling of being unwell3,4322.9%
Weight decreasedweight loss3,3992.9%
Drug interactionan interaction between medicines3,2242.8%
Astheniaweakness or lack of energy3,1542.7%
Hyperkalaemiahigh blood potassium3,0722.6%
Dizzinesslight-headedness or unsteadiness3,0702.6%
Renal failurekidney failure3,0102.6%
Headachehead pain2,8642.5%
Overdosea dose above the recommended amount2,8332.4%
Off label useused for a purpose or in a way not on the label2,8062.4%
Abdominal painstomach or belly pain2,7472.4%
Renal failure acute2,4742.1%
Painpain, site not specified2,4322.1%
Intentional overdosea deliberate overdose2,4132.1%
Falla fall2,3912.1%
Confusional stateconfusion2,3322%
Dehydration2,3172%
Condition aggravatedthe condition being treated got worse2,2111.9%
Abdominal discomfortstomach discomfort2,1841.9%
Decreased appetitereduced appetite2,1441.8%
Arthralgiajoint pain2,1191.8%
Diabetes mellitus inadequate controldiabetes not well controlled2,0931.8%
Hypertensionhigh blood pressure2,0501.8%
Diabetic ketoacidosisa serious complication of diabetes with acid build-up1,9181.6%
Hyperglycaemiahigh blood sugar1,9181.6%
Abdominal pain upperupper stomach pain1,9021.6%
Shockshock, a collapse of the circulation1,8841.6%
Glycosylated haemoglobin increaseda raised HbA1c, the long-term sugar measure1,8381.6%
Pain in extremitypain in an arm or leg1,8221.6%
Weight increasedweight gain1,8051.5%
Pneumonialung infection1,7931.5%
Deaththe patient died; cause not stated by this term1,7701.5%
Pyrexiafever1,7171.5%
Drug hypersensitivityan allergic-type reaction (the term names a medicine)1,7161.5%
Cardiac arrestthe heart stopped1,7081.5%
Renal impairmentreduced kidney function1,6961.5%

Download all 2,970 terms of the class (CSV)

The counts add to more than 116,598 reports, because one report can record more than one term. FDA says:

No individual drug is connected to any individual reaction. When a report lists multiple drugs and multiple reactions, there is no way to conclude from the data therein that a given drug is responsible for a given reaction.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

Reports by month

Reports that name a biguanide drug, by month, five years to June 2026
05001,00020222023202420252026

FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.

Outcomes, patients and reporters

Outcomes in the reports of the class Biguanide
OutcomeReportsShareShare as a bar
Death16,18313.9%
Life-threatening14,45012.4%
Hospitalization (initial or prolonged)50,21943.1%
Disability or Permanent Damage3,1722.7%
Congenital Anomaly/Birth Defect1,7601.5%
Other Serious (Important Medical Events)58,18949.9%
Not serious21,80118.7%

An outcome in a report is not proof that a drug was the cause. The reporter gives the outcome, and FDA does not verify it. A report can have more than one outcome. FDA says:

The information in these reports has not been scientifically or otherwise verified as to a cause and effect relationship and cannot be used to estimate the incidence of these events.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

Age of the patient in the reports of the class Biguanide
AgeReportsShareShare as a bar
Under 24250.4%
2 to 111760.2%
12 to 171,1201%
18 to 449,8818.5%
45 to 6430,24525.9%
65 to 7422,02218.9%
75 and over17,80715.3%
Age not given34,92230%
Type of reporter in the reports of the class Biguanide
ReporterReportsShareShare as a bar
Physician32,97328.3%
Pharmacist9,9288.5%
Other health professional35,39530.4%
Lawyer4290.4%
Consumer or non-health professional33,07728.4%
Not given4,7964.1%

Official pages

The site checked these addresses on . The links open in a new tab.

Cite this page

Reported Reactions. Biguanide: adverse event reports that FDA received. https://reportedreactions.com/class/biguanide/ Source: U.S. Food and Drug Administration, openFDA Drug Adverse Event (FAERS) files, release of . Reports received through .

Where the data come from

The counts come from the openFDA Drug Adverse Event (FAERS) bulk files, release of 29 Oct 2026. The files have the reports that FDA received through 30 Jun 2026. A drug name is the name on the report. The site matches it to a brand name or a generic name of the National Drug Code Directory of 2 Nov 2026. A class is the pharmacologic class (EPC) of the FDA label.

The class of a drug is the Established Pharmacologic Class that openFDA attaches to its reports most often. When the reports have none, it is the class in the NDC Directory. The site does not publish a report narrative, a lot number, a detail of a patient or the identity of a reporter. The record of FDA is the authority. See how the site counts reports, the data sources and the corrections page.

Questions

Which drugs are in the Biguanide class on this site?

Actoplus Met, Invokamet, Janumet, Metformin, Metformin hcl, Metformin hydrochloride and 1 more, in order of name. The class of a drug comes from the pharmacologic class (EPC) on its FDA label.

Can the table of drugs rank the drugs?

No. FDA says:

Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

Common products may have a higher number of adverse events due to the higher total number of people using the product.

Source: openFDA, Drug Adverse Event Overview. The site read the page on .

Drugs also differ in the conditions that they treat and in their time on the market.

How does a person report an adverse event?

FDA runs MedWatch, a program that takes voluntary reports from health professionals, patients and consumers. The guide on how to report has the links.