Metformin

Metformin Brand Names

Fortamet | Glucophage | Glucophage XR | Glumetza | Riomet | RIOMET ER

What is Metformin

Metformin is an oral biguanide used to improve glycemic control in adult and pediatric patients 10 years and older with type 2 diabetes mellitus (DM).

The actions of metformin differ from, yet complement, those of other antidiabetic therapies.

Metformin is first-line in the treatment of type 2 DM. The combination of metformin with lifestyle interventions should be initiated in most patients at the time of diagnosis of type 2 DM.

Metformin was chosen as the initial drug therapy based on its efficacy, safety, and cost.

While metformin carries a low risk for lactic acidosis as outlined in the prescribing information and boxed warning of all metformin-containing products, care in prescribing and monitoring can reduce this risk.

In patients with established cardiovascular (CV) disease, heart failure (HF), or chronic kidney disease (CKD), a sodium-glucose co-transporter 2 (SGLT2) inhibitor or glucagon-like peptide-1 receptor agonist (GLP-1 RA) with proven CV benefit and reduction of CKD progression is recommended for add-on therapy, independent of baseline A1C or individualized A1C target.

In a follow-up study to the UKPDS, researchers found that after 10-years of resuming typical care, patients originally randomized to metformin therapy had a 33% relative reduction in the risk of myocardial infarction and a 27% relative reduction in the risk of death from any cause as compared to patients receiving conventional therapy; the reductions in cardiovascular risk persisted even though A1C concentrations were similar in the 2 groups after 1 year of follow-up.

In patients with prediabetes, metformin reduces the risk of future diabetes by 25% to 30% and may confer cardiovascular benefit.

Metformin has been found useful in the off-label treatment of polycystic ovary syndrome (PCOS); it lowers serum androgens and restores normal menstrual cycles and ovulation, and may improve pregnancy rates.

Additionally, limited data indicate that it may delay puberty onset in females with precocious puberty and delay menarche onset in females with early-normal onset of puberty.

Indications

1. drug-induced obesity
2. gestational diabetes
3. infertility
4. insulin resistance
5. polycystic ovary syndrome
6. precocious puberty
7. prediabetes
8. prolongation of pubertal growth
9. type 2 diabetes mellitus

Side Effects

1. abdominal pain
2. anorexia
3. chest pain (unspecified)
4. chills
5. cholestasis
6. diarrhea
7. dizziness
8. dysgeusia
9. dyspepsia
10. elevated hepatic enzymes
11. flatulence
12. flushing
13. folate deficiency
14. headache
15. hepatitis
16. hyperhidrosis
17. hypoglycemia
18. infection
19. lactic acidosis
20. malaise
21. megaloblastic anemia
22. metabolic acidosis
23. metallic taste
24. myalgia
25. nausea
26. palpitations
27. rash
28. rhabdomyolysis
29. vitamin B12 deficiency
30. vomiting
31. weight loss

Monitoring Parameters

• blood glucose
• CBC
• glycosylated hemoglobin A1c (HbA1c)
• LFTs
• serum creatinine/BUN

Contraindications

• acidemia
• acute heart failure
• acute myocardial infarction
• adrenal insufficiency
• alcoholism
• breast-feeding
• burns
• cardiac disease
• cardiogenic shock
• children
• dehydration
• diabetic ketoacidosis
• diarrhea
• ethanol ingestion
• ethanol intoxication
• fever
• gastroparesis
• geriatric
• GI obstruction
• heart failure
• hepatic disease
• hypercortisolism
• hyperglycemia
• hyperthyroidism
• hypoglycemia
• hypothyroidism
• hypoxemia
• ileus
• infants
• infection
• lactic acidosis
• malnutrition
• metabolic acidosis
• pernicious anemia
• pituitary insufficiency
• polycystic ovary syndrome
• pregnancy
• radiographic contrast administration
• renal disease
• renal failure
• renal impairment
• sepsis
• surgery
• trauma
• type 1 diabetes mellitus
• vomiting

Do not use metformin in patients who have a known metformin hypersensitivity.

Interactions

• Abacavir; Dolutegravir; Lamivudine
• Abacavir; Lamivudine, 3TC
• Abacavir; Lamivudine, 3TC; Zidovudine, ZDV
• Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine
• Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine
• Acetaminophen; Chlorpheniramine; Phenylephrine; Phenyltoloxamine
• Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine
• Acetaminophen; Dextromethorphan; Phenylephrine
• Acetaminophen; Dextromethorphan; Pseudoephedrine
• Acetaminophen; Guaifenesin; Phenylephrine
• Acetaminophen; Propoxyphene
• Acetaminophen; Pseudoephedrine
• Acetazolamide
• Acetohexamide
• Acrivastine; Pseudoephedrine
• Adefovir
• Aliskiren; Amlodipine; Hydrochlorothiazide, HCTZ
• Aliskiren; Hydrochlorothiazide, HCTZ
• Aliskiren; Valsartan
• Amiloride; Hydrochlorothiazide, HCTZ
• Amlodipine; Benazepril
• Amlodipine; Hydrochlorothiazide, HCTZ; Olmesartan
• Amlodipine; Hydrochlorothiazide, HCTZ; Valsartan
• Amlodipine; Olmesartan
• Amlodipine; Telmisartan
• Amlodipine; Valsartan
• Amoxicillin; Clarithromycin; Lansoprazole
• Amoxicillin; Clarithromycin; Omeprazole
• Amphetamine
• Amphetamine; Dextroamphetamine
• Amphetamines
• Androgens
• Angiotensin II receptor antagonists
• Angiotensin-converting enzyme inhibitors
• Atazanavir; Cobicistat
• Atenolol; Chlorthalidone
• atypical antipsychotic
• Azilsartan
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• Benazepril
• Benazepril; Hydrochlorothiazide, HCTZ
• Bendroflumethiazide; Nadolol
• Benzphetamine
• Beta-blockers
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• Bisoprolol; Hydrochlorothiazide, HCTZ
• Bortezomib
• Brigatinib
• Brompheniramine; Carbetapentane; Phenylephrine
• Brompheniramine; Dextromethorphan; Phenylephrine
• Brompheniramine; Hydrocodone; Pseudoephedrine
• Brompheniramine; Pseudoephedrine
• Bumetanide
• Candesartan
• Candesartan; Hydrochlorothiazide, HCTZ
• Capmatinib
• Captopril
• Captopril; Hydrochlorothiazide, HCTZ
• Carbetapentane; Chlorpheniramine; Phenylephrine
• Carbetapentane; Diphenhydramine; Phenylephrine
• Carbetapentane; Guaifenesin; Phenylephrine
• Carbetapentane; Phenylephrine
• Carbetapentane; Phenylephrine; Pyrilamine
• Carbetapentane; Pseudoephedrine
• Carbinoxamine; Dextromethorphan; Pseudoephedrine
• Carbinoxamine; Hydrocodone; Phenylephrine
• Carbinoxamine; Hydrocodone; Pseudoephedrine
• Carbinoxamine; Phenylephrine
• Carbinoxamine; Pseudoephedrine
• Cephalexin
• Cetirizine; Pseudoephedrine
• Chlophedianol; Dexchlorpheniramine; Pseudoephedrine
• Chlophedianol; Guaifenesin; Phenylephrine
• Chloroquine
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• Chlorpheniramine; Dextromethorphan; Phenylephrine
• Chlorpheniramine; Dihydrocodeine; Phenylephrine
• Chlorpheniramine; Dihydrocodeine; Pseudoephedrine
• Chlorpheniramine; Guaifenesin; Hydrocodone; Pseudoephedrine
• Chlorpheniramine; Hydrocodone; Phenylephrine
• Chlorpheniramine; Hydrocodone; Pseudoephedrine
• Chlorpheniramine; Phenylephrine
• Chlorpheniramine; Pseudoephedrine
• Chlorpropamide
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• Emtricitabine
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• Emtricitabine; Rilpivirine; Tenofovir disoproxil fumarate
• Emtricitabine; Tenofovir alafenamide
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• Enalapril, Enalaprilat
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• Enalapril; Hydrochlorothiazide, HCTZ
• Entecavir
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• Ethinyl Estradiol; Norgestimate
• Ethinyl Estradiol; Norgestrel
• Ethotoin
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• Famotidine
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• Garlic, Allium sativum
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• Glipizide
• Glipizide; Metformin
• Glyburide
• Glyburide; Metformin
• Glycopyrrolate
• Glycopyrrolate; Formoterol
• Green Tea
• Guaifenesin; Hydrocodone; Pseudoephedrine
• Guaifenesin; Phenylephrine
• Guaifenesin; Pseudoephedrine
• Hydralazine; Hydrochlorothiazide, HCTZ
• Hydrochlorothiazide, HCTZ
• Hydrochlorothiazide, HCTZ; Irbesartan
• Hydrochlorothiazide, HCTZ; Lisinopril
• Hydrochlorothiazide, HCTZ; Losartan
• Hydrochlorothiazide, HCTZ; Methyldopa
• Hydrochlorothiazide, HCTZ; Metoprolol
• Hydrochlorothiazide, HCTZ; Moexipril
• Hydrochlorothiazide, HCTZ; Olmesartan
• Hydrochlorothiazide, HCTZ; Propranolol
• Hydrochlorothiazide, HCTZ; Quinapril
• Hydrochlorothiazide, HCTZ; Spironolactone
• Hydrochlorothiazide, HCTZ; Telmisartan
• Hydrochlorothiazide, HCTZ; Triamterene
• Hydrochlorothiazide, HCTZ; Valsartan
• Hydrocodone; Phenylephrine
• Hydrocodone; Potassium Guaiacolsulfonate; Pseudoephedrine
• Hydrocodone; Pseudoephedrine
• Hydroxychloroquine
• Hydroxyprogesterone
• Ibuprofen; Pseudoephedrine
• Indacaterol; Glycopyrrolate
• Indapamide
• Insulin Aspart
• Insulin Aspart; Insulin Aspart Protamine
• Insulin Degludec
• Insulin Degludec; Liraglutide
• Insulin Detemir
• Insulin Glargine
• Insulin Glargine; Lixisenatide
• Insulin Glulisine
• Insulin Lispro
• Insulin Lispro; Insulin Lispro Protamine
• Insulin, Inhaled
• Insulins
• Iodipamide Meglumine
• Ionic Contrast Media
• Ioxaglate Meglumine; Ioxaglate Sodium
• Irbesartan
• Isophane Insulin (NPH)
• Lamivudine, 3TC
• Lamivudine, 3TC; Zidovudine, ZDV
• Lamivudine; Tenofovir Disoproxil Fumarate
• Lamotrigine
• Lanreotide
• Ledipasvir; Sofosbuvir
• Lente Insulin
• Leuprolide; Norethindrone
• Levomefolate
• Levonorgestrel
• Levothyroxine
• Levothyroxine; Liothyronine (Porcine)
• Levothyroxine; Liothyronine (Synthetic)
• Linezolid
• Liothyronine
• Lisdexamfetamine
• Lisinopril
• Lithium
• Lomefloxacin
• Loratadine; Pseudoephedrine
• Lorcaserin
• Losartan
• Lovastatin; Niacin
• Mecasermin rinfabate
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• Medroxyprogesterone
• Meglitinides
• Memantine
• Mestranol; Norethindrone
• Metformin; Repaglinide
• Methamphetamine
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• Metolazone
• Metyrapone
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• Moexipril
• Monoamine oxidase inhibitors
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• Nateglinide
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• Niacin, Niacinamide
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• Nicotine
• Nifedipine
• Non-Ionic Contrast Media
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• Norgestrel
• Octreotide
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• Orlistat
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• Oxymetholone
• Pasireotide
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• Pentoxifylline
• Perindopril
• Perindopril; Amlodipine
• Phenothiazines
• Phentermine; Topiramate
• Phenylephrine
• Phenylephrine; Promethazine
• Phenytoin
• Prasterone, Dehydroepiandrosterone, DHEA (Dietary Supplements)
• Prasterone, Dehydroepiandrosterone, DHEA (FDA-approved)
• Progesterone
• Progestins
• Propantheline
• Propoxyphene
• Protease inhibitors
• Pseudoephedrine
• Pyrimethamine; Sulfadoxine
• Quinapril
• Quinolones
• Ramipril
• Ranolazine
• Regular Insulin
• Regular Insulin; Isophane Insulin (NPH)
• Repaglinide
• Reserpine
• Sacubitril; Valsartan
• Salicylates
• Segesterone Acetate; Ethinyl Estradiol
• Sofosbuvir
• Sofosbuvir; Velpatasvir
• Sofosbuvir; Velpatasvir; Voxilaprevir
• Somatropin, rh-GH
• Sparfloxacin
• Sulfadiazine
• Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole
• Sulfasalazine
• Sulfisoxazole
• Sulfonamides
• Sulfonylureas
• Tacrolimus
• Tafenoquine
• Tegaserod
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• Tenofovir Alafenamide
• Tenofovir, PMPA
• Testolactone
• Testosterone
• Thiazide diuretics
• Thyroid hormones
• tobacco
• Tolazamide
• Tolbutamide
• Topiramate
• Torsemide
• Trandolapril
• Trandolapril; Verapamil
• Trospium
• Ultralente Insulin
• Valsartan
• Vandetanib
• Zonisamide