Prescription medicine
Metformin Brand names: Glumetza, Riomet; first approved as Glucophage
Metformin (Glucophage) is a prescription medicine with an FDA approval on record since 1995. FDA's NDC Directory lists it from 80 generic labelers, and pharmacies paid $0.0145 per metformin HCl 500 mg tablet in the October 7, 2026 NADAC survey.
- Generic listed
- Boxed warning
Check it at the source: the metformin FDA label on DailyMed (effective September 3, 2026, Granules India Ltd); the NDA 20357 record on Drugs@FDA; every metformin label on DailyMed.
Highlights of the record
FDA label of September 3, 2026; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026; NADAC October 7, 2026
WARNING: LACTIC ACIDOSIS.
Postmarketing cases of metformin-associated lactic acidosis have resulted in death, hypothermia, hypotension, and resistant bradyarrhythmias. The onset of metformin-associated lactic acidosis is often subtle, accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, somnolence, and abdominal pain. Metformin-associated lactic acidosis was characterized by elevated blood lactate levels (>5 mmol/Liter), anion gap acidosis (without evidence of ketonuria or ketonemia), an increased lactate/pyruvate ratio, and metformin plasma levels generally >5 mcg/mL [see Warnings and Precautions (5.1)]. Risk factors for metformin-associated lactic acidosis include renal impairment, concomitant use of certain drugs (e.g., carbonic anhydrase inhibitors such as topiramate), age 65 years old or greater, having a radiological study with contrast, surgery and other procedures, hypoxic states (e.g., acute congestive heart failure), excessive alcohol intake, hepatic impairment, and mitochondrial diseases [see Warnings and Precautions (5.1)]. Steps to reduce the risk of and manage metformin-associated lactic acidosis in these high risk groups are provided in the full prescribing information [see Dosage and Administration (2.2), Contraindications (4), Warnings and Precautions (5.1), and Drug Interactions (7) ]. […]
Used for
From the label: indications and usageMetformin hydrochloride extended-release tablets are indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus.
Forms and strengths
- 500 mg
- 625 mg
- 750 mg
- 850 mg
- 1000 mg
- 500 mg/5ml
Extended-release tablet; tablet; film-coated tablet; film-coated extended-release tablet; coated tablet.
On the market
- Earliest approval on file
- March 3, 1995 Glucophage, Emd Serono Inc; Drugs@FDA’s file, where older or withdrawn approvals can be missing
- Generic approvals
- 103 first January 24, 2002; 57 with a marketed status in Drugs@FDA
- Labelers listed (NDC)
- 82 of which 80 under generic applications, 2 under brand applications, repackagers included
- Last listed patent
- May 1, 2035 Riomet ER for oral suspension; not a generic launch date
Supply and safety
- Pharmacy cost (NADAC)
- $0.0145 per tablet Metformin HCl 500 mg tablet
- Shortage (FDA)
- No current entry
- Recalls by its makers (FDA)
- 61 since 2011 1 Class I among all firms' recalls; latest March 13, 2025; 1 more by firms not listed as its makers
- FAERS reports
- 410,076 through July 30, 2026
What is metformin used for?
From the label: indications and usageMetformin hydrochloride extended-release tablets are indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Metformin hydrochloride extended-release tablets are biguanide indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus
Conditions named in the indications of metformin's FDA labels, with every medicine labeled for each:
FDA pharmacologic class: Biguanide.
Source: FDA drug label (METFORMIN HYDROCHLORIDE), Granules India Ltd, effective September 3, 2026 (SPL set 73197cb5-3e23-4ac0-b189-f9bc848bce66), via openFDA; the full label on DailyMed
What does the patient leaflet for metformin say first?
The FDA-approved Medication Guide or Patient Information that comes with the medicine, in its own words.
From the patient leaflet: What is the most important information I should know about metformin hydrochloride extended release tablets?Serious side effects can happen in people taking metformin hydrochloride extended-release tablets, including: Lactic Acidosis. Metformin hydrochloride, the medicine in metformin hydrochloride extended-release tablets, can cause a rare, but serious, side effect called lactic acidosis (a build-up of lactic acid in the blood) that can cause death. Lactic acidosis is a medical emergency and must be treated in a hospital. Stop taking metformin hydrochloride extended-release tablets and call your healthcare provider right away if you get any of the following symptoms of lactic acidosis: feel very weak and tired have unusual (not normal) muscle pain have trouble breathing have unusual sleepiness or sleep longer than usual have unexplained stomach or intestinal problems with nausea and vomiting, or diarrhea feel cold, especially in your arms and legs feel dizzy or lightheaded have a slow or irregular heartbeat You have a higher chance of getting lactic acidosis if you: have kidney problems. People whose kidneys are not working properly should not take metformin hydrochloride extended-release tablets. have liver problems. have congestive heart failure that requires treatment with medicines. drink a lot of alcohol (very often or short-term "binge" drinking). get dehydrated (lose a large amount of body fluids). This can happen if you are sick with a fever, vomiting, or diarrhea. […]
From the patient leaflet: What should I avoid while taking metformin hydrochloride extended-release tablets?Do not drink a lot of alcoholic drinks while taking metformin hydrochloride extended-release tablets. This means you should not binge drink for short periods, and you should not drink a lot of alcohol on a regular basis. Alcohol can increase the chance of getting lactic acidosis.
From the patient leaflet: How should I store metformin hydrochloride extended-release tablets?Store metformin hydrochloride extended-release tablets at 20°–25°C (68°–77°F). Keep metformin hydrochloride extended-release tablets and all medicines out of the reach of children.
Source: FDA drug label (Metformin Hydrochloride), Unichem Pharmaceuticals (USA), Inc., effective July 1, 2026 (SPL set 9eebed09-2562-4d21-b3b3-c06562fe3f99), via openFDA; the full label on DailyMed
Is there a generic for metformin (Glucophage)?
The FDA approved the first generic metformin on January 24, 2002. 103 generic applications are approved; 57 of them carry a current (not discontinued) marketing status in Drugs@FDA; that status is not evidence that the generic is on sale.
FDA's NDC Directory lists metformin from 80 labelers under a generic (ANDA) application and from 2 brand labelers. A listing means the company has registered the product for sale; it does not show that every pharmacy stocks it.
The Orange Book lists no patent for Glucophage tablets; a patent listed only for Riomet ER for oral suspension runs to May 1, 2035. A patent or exclusivity date is not the date a generic goes on sale: court cases and settlements move it either way.
- 1995 earliest approval on file
- 2002 first generic approved
- 2035 last listed patent
- red ticks recalls
Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)
What do pharmacies pay for metformin (Glucophage)?
In CMS's NADAC survey of October 7, 2026, pharmacies paid $0.0145 per Metformin HCl 500 mg tablet, down 1% from $0.0147 on October 8, 2025. Prices per unit in the table differ many-fold by strength, form and brand, so compare like with like. The chart's scale runs from the lowest to the highest price shown, not from zero. NADAC is what retail pharmacies paid their wholesalers, per unit, in CMS's monthly survey; what a patient pays depends on insurance and the pharmacy.
- Metformin HCl 500 mg tablet (generic)
| Strength and form | Brand or generic | Pharmacy cost | 30 tablets, or one pen or vial | 12-month change |
|---|---|---|---|---|
| Metformin ER 1,000 mg gastric-retentive tablet | Generic | $0.336 per tablet many times the lowest per-tablet cost; NADAC records the price, not why | $10.07 | -34% |
| Metformin ER 1,000 mg osmotic tablet | Generic | $0.314 per tablet many times the lowest per-tablet cost; NADAC records the price, not why | $9.43 | +5% |
| Metformin ER 500 mg gastric-retentive tablet | Generic | $0.271 per tablet | $8.13 | -22% |
| Metformin ER 500 mg osmotic tablet | Generic | $0.164 per tablet | $4.93 | +1% |
| Metformin HCl 1,000 mg tablet | Generic | $0.0232 per tablet | $0.695 | -2% |
| Metformin HCl 500 mg tablet | Generic | $0.0145 per tablet | $0.435 | -1% |
| Metformin HCl 500 mg/5 mL solution | Generic | $0.383 per mL | n/a | -42% |
| Metformin HCl 625 mg tablet | Generic | $12.53 per tablet many times the lowest per-tablet cost; NADAC records the price, not why | $375.80 | -3% |
| Metformin HCl 750 mg tablet | Generic | $14.61 per tablet many times the lowest per-tablet cost; NADAC records the price, not why | $438.15 | no change |
| Metformin HCl 850 mg tablet | Generic | $0.024 per tablet | $0.719 | +7% |
| Metformin HCl ER 500 mg tablet | Generic | $0.0284 per tablet | $0.851 | -3% |
| Metformin HCl ER 750 mg tablet | Generic | $0.0526 per tablet | $1.58 | +0.2% |
Source: CMS National Average Drug Acquisition Cost (NADAC) survey, October 7, 2026: what retail pharmacies paid per unit; not a counter price
Has metformin been recalled?
The FDA's Enforcement Report lists 62 recalls naming metformin since 2011: 1 Class I (the most serious), 57 Class II, 4 Class III; 13 still ongoing. 1 of them is by a firm that FDA's NDC Directory does not list as a maker of metformin and that holds no application for it in Drugs@FDA, such as compounding pharmacies or bulk-ingredient suppliers; the recall notice names the product recalled. A recall names products and lots, not every product of the medicine.
| Started | Class | Company | Reason |
|---|---|---|---|
| March 13, 2025 | Class II | Glenmark Pharmaceuticals Inc., USA | CGMP Deviations |
| February 25, 2025 | Class II | A-S Medication Solutions LLC | Presence of Foreign Tablets/Capsules. |
| December 30, 2024 | Class II | Granules Pharmaceuticals Inc. | Presence of Foreign Tablets/Capsules: A Paracetamol 500 mg tablet was found in a 1000-count bottle of Metformin HCL ER Tablets USP, 500 mg. |
| February 22, 2023 | Class II | Teva Pharmaceuticals USA Inc | CGMP Deviations: Detection of N-Nitrosodimethylamine (NDMA) levels in excess of the Acceptable Daily Intake Limit. |
| December 30, 2021 | Class II | RemedyRepack Inc. | CGMP Deviations: Detection of N-Nitrosodimethylamine (NDMA) levels in excess of the Acceptable Daily Intake Limit. |
| December 27, 2021 | Class II | VIONA PHARMACEUTICALS INC | CGMP Deviations- Detection of N-Nitrosodimethylamine (NDMA) levels in excess of the Acceptable Daily Intake Limit. |
| June 1, 2021 | Class II | VIONA PHARMACEUTICALS INC | CGMP Deviations: Detection of N-Nitrosodimethylamine (NDMA) levels in excess of the Acceptable Daily Intake Limit. |
| May 4, 2021 | Class II | SUN PHARMACEUTICAL INDUSTRIES INC | Presence of foreign substance: identified as activated carbon. |
Source: FDA Enforcement Report (drug recalls) via openFDA, through October 8, 2026
What does the metformin label say about other medicines?
The metformin label names 10 other medicines in its interaction, contraindication or warning sections. The labels of 39 other medicines name metformin. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.
| Medicine named | Section | What the label says |
|---|---|---|
| Acetazolamide | drug interactions | Carbonic Anhydrase Inhibitors Clinical Impact: Carbonic anhydrase inhibitors frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of these drugs with metformin hydrochloride extended-release tablets may increase the … Intervention: Consider more frequent monitoring of these patients. Examples: Topiramate, zonisamide, acetazolamide or dichlorphenamide. |
| Cimetidine | drug interactions | Drugs that Reduce Metformin Hydrochloride Extended-Release Tablets Clearance Clinical Impact: Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (…) could increase systemic exposure to metformin and may increase the risk for lactic acidosis. Intervention: Consider the benefits and risks of concomitant use with metformin hydrochloride extended-release tablets. Examples: Ranolazine, vandetanib, dolutegravir, and cimetidine. |
| Dichlorphenamide | drug interactions | Carbonic Anhydrase Inhibitors Clinical Impact: Carbonic anhydrase inhibitors frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of these drugs with metformin hydrochloride extended-release tablets may increase the … Intervention: Consider more frequent monitoring of these patients. Examples: Topiramate, zonisamide, acetazolamide or dichlorphenamide. |
| Dolutegravir | drug interactions | Drugs that Reduce Metformin Hydrochloride Extended-Release Tablets Clearance Clinical Impact: Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (…) could increase systemic exposure to metformin and may increase the risk for lactic acidosis. Intervention: Consider the benefits and risks of concomitant use with metformin hydrochloride extended-release tablets. Examples: Ranolazine, vandetanib, dolutegravir, and cimetidine. |
| Isoniazid | drug interactions | Clinical Impact: Certain drugs tend to produce hyperglycemia and may lead to loss of glycemic control. … phenytoin, nicotinic acid, sympathomimetics, calcium channel blockers, and isoniazid. |
| Phenytoin | drug interactions | Clinical Impact: Certain drugs tend to produce hyperglycemia and may lead to loss of glycemic control. … corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blockers, and isoniazid. |
| Ranolazine | drug interactions | Drugs that Reduce Metformin Hydrochloride Extended-Release Tablets Clearance Clinical Impact: Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (…) could increase systemic exposure to metformin and may increase the risk for lactic acidosis. Intervention: Consider the benefits and risks of concomitant use with metformin hydrochloride extended-release tablets. Examples: Ranolazine, vandetanib, dolutegravir, and cimetidine. |
| Topiramate | boxed warning | Risk factors for metformin-associated lactic acidosis include renal impairment, concomitant use of certain drugs (e.g., carbonic anhydrase inhibitors such as topiramate), age 65 years old or greater, having a radiological study with contrast, surgery and other procedures, hypoxic states (e.g., acute congestive heart … |
| Vandetanib | drug interactions | Drugs that Reduce Metformin Hydrochloride Extended-Release Tablets Clearance Clinical Impact: Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (…) could increase systemic exposure to metformin and may increase the risk for lactic acidosis. Intervention: Consider the benefits and risks of concomitant use with metformin hydrochloride extended-release tablets. Examples: Ranolazine, vandetanib, dolutegravir, and cimetidine. |
| Zonisamide | drug interactions | Carbonic Anhydrase Inhibitors Clinical Impact: Carbonic anhydrase inhibitors frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of these drugs with metformin hydrochloride extended-release tablets may increase the … Intervention: Consider more frequent monitoring of these patients. Examples: Topiramate, zonisamide, acetazolamide or dichlorphenamide. |
Other labels that name metformin
Source: FDA drug label (METFORMIN HYDROCHLORIDE), Granules India Ltd, effective September 3, 2026 (SPL set 73197cb5-3e23-4ac0-b189-f9bc848bce66), via openFDA; the full label on DailyMed
What do FAERS reports show for metformin?
The FDA Adverse Event Reporting System holds 410,076 reports that list metformin among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 33,853 are coded as a death and 144,551 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.
Reports received each year
The most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026
What else is labeled for the same conditions as metformin?
21 other medicines are given the same way (oral) and in the same FDA class as metformin or labeled mainly for the same use (type 2 diabetes), the same class first. Type 2 diabetes lists all 52 medicines labeled for it, by any route. The first 8 are below. They are listed as records, not as substitutes: whether one can replace another is a prescriber's decision.
| Medicine | Shared indication | Generic labelers (oral) | Pharmacy cost | Shortage |
|---|---|---|---|---|
| Glipizide | Type 2 diabetes | 31 labelers | $0.0339 per tablet 5 mg tablet | No current entry |
| Glimepiride | Type 2 diabetes | 29 labelers | $0.0507 per tablet 4 mg tablet | No current entry |
| Pioglitazone | Type 2 diabetes | 22 labelers | $0.0675 per tablet 15 mg tablet | No current entry |
| Glyburide | Type 2 diabetes | 16 labelers | $0.0643 per tablet 5 mg tablet | A presentation being discontinued |
| Sitagliptin | Type 2 diabetes | 4 labelers | $3.77 per tablet 100 mg tablet | No current entry |
| Repaglinide | Type 2 diabetes | 7 labelers | $0.0987 per tablet 1 mg tablet | No current entry |
| Nateglinide | Type 2 diabetes | 9 labelers | $0.179 per tablet 60 mg tablet | No current entry |
| Acarbose | Type 2 diabetes | 6 labelers | $0.274 per tablet 100 mg tablet | No current entry |
Source: FDA drug labels (indications), NDC Directory, NADAC of October 7, 2026, FDA shortages (October 8, 2026)
How does metformin compare with medicines for the same use?
10 side-by-side pages set metformin beside a medicine whose label shares a use: approvals, generics, pharmacy cost, warnings and supply.
What next?
- Alternatives to metformin
- 21 medicines for the same use
- Other biguanides
- the pharmacologic class, with prices and generics
- Metformin side effects
- the label's list beside FAERS reports
- Check an interaction
- what two or more labels say about each other