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Metformin

Metformin

Metformin belongs to the class of medications called oral hypoglycemics, which are medications that lower blood sugar. It is used to control blood glucose (blood sugar) for people with Type 2 Diabetes.

Available form

Tablet, Tablet

Dosage

500mg, 850mg, 1000mg

Manufacturers

Angita Pharma, Apotex, Auro Pharma, Dominion Pharmacal, Jamp Pharma Corporation, Laboratoire Riva, Mantra Pharma, Marcan Pharmaceuticals, Mint Pharmaceuticals, Mylan Pharmaceuticals

Branded drugs

Glucophage, Glumetza

Buy Metformin Full drug details

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Metformin information

Dosage

Side Effects

Available Form

Contraindications

Precautions

Warnings

Directions of use

The recommended adult dose of metformin ranges from 500 mg 3 or 4 times a day to 850 mg 2 or 3 times a day. The maximum daily dose should not exceed 2,550 mg. Tablets should be taken with food whenever possible to reduce the risk of nausea and vomiting. Metformin may be used alone or with other medications that reduce blood sugar. To ensure that the medication is working well, monitor your blood glucose on a regular basis as directed by your doctor or diabetes educator.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take Metformin exactly as prescribed by your doctor. If you miss a dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store Metformin at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Metformin. If you are concerned about side effects, discuss the risks and benefits of Metformin with your doctor.

The following side effects have been reported by at least 1% of people taking Metformin. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

Diarrhea
dizziness or lightheadedness
increased sensitivity of skin to the sun
loss of appetite
metallic taste in mouth
nausea
passing of gas
stomach ache
vomiting
weight loss

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

decreased coordination
feeling cold
feeling extremely weak, tired, or uncomfortable
low blood sugar (mild), including:

anxiety
behavioural changes similar to being drunk
blurred vision
cold sweats
confusion
cool, pale skin
difficulty concentrating
drowsiness
excessive hunger
fast heartbeat
headache
nausea
nervousness
nightmares
restless sleep
shakiness
slurred speech

peripheral Neuropathy (e.g., numbness, prickling, tingling in hands or feet)
signs of Anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath, rapid heartbeat, dark urine)
slow or irregular heart beat
thinking difficulties (e.g., poor decision making, decreased concentration, twitching, trembling, trouble speaking or swallowing)
trouble breathing
unusual muscle pain

Stop taking the medication and seek immediate medical attention if any of the following occur:

lactic acidosis (quick and severe), including:

fast, shallow breathing
muscle pain or cramping
slow or irregular heartbeat
unusual sleepiness
unusual stomach ache (after the initial stomach ache that can occur at the start of therapy)
unusual tiredness or weakness

seizure
signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, Fever, chills, rapid heartbeat, swollen abdomen)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Metformin.

There may be an interaction between metformin and any of the following:

Acetazolamide
acetylsalicylic acid (Asa)
alcohol
angiotensin converting enzyme inhibitors (ACEIs; Captopril, Enalapril, Ramipril)
antipsychotics (e.g., Clozapine, Olanzapine, Quetiapine, Risperidone)
beta 2 agonists (e.g., salbutamol, formoterol, terbutaline)
birth control pills
Brinzolamide
Bupropion
calcium channel blockers (e.g., Amlodipine, Diltiazem, Nifedipine, Verapamil)
Cephalexin
Cimetidine
corticosteroids (e.g., Dexamethasone, Prednisone)
Danazol
decongestants (e.g., phenylephrine, Pseudoephedrine)
diabetic drugs (e.g., Glyburide, insulin, Repaglinide, Sitagliptin)
Disopyramide
diuretics (water pills; e.g., Amiloride, Furosemide, Hydrochlorothiazide)
dofetilide
dolutegravir
estrogens (e.g., conjugated estrogen, Estradiol, ethinyl estradiol)
Glucagon
glycopyrrolate
Hepatitis C antivirals (e.g., dasabuvir, ombitasvir, paritaprevir, ritonavir)
HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
iodinated contrast material
Lamotrigine
Lanreotide
mifepristone
monoamine oxidase inhibitors (M.O.S. e.g., Moclobemide, Phenelzine, Rasagiline, Selegiline, Tranylcypromine)
nicotinic acid (Niacin)
Octreotide
Ondansetron
Pasireotide
Pegvisomant
pentamidine
Phenytoin
procainamide
progestins (e.g., Dienogest, Levonorgestrel, medroxyprogesterone, Norethindrone)
quinine
quinolone antibiotics (e.g., ciprofloxacin, Norfloxacin, Ofloxacin)
selective serotonin reuptake inhibitors (SSRIs; e.g., Citalopram, Fluoxetine, Paroxetine, Sertraline)
Somatropin
sulfonamide antibiotics ("sulfas"; e.g., sulfisoxazole, sulfamethoxazole)
Sunitinib
Tacrolimus
testosterone
Thyroid products
Topiramate
Trimethoprim

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

stop taking one of the medications,
change one of the medications to another,
change how you are taking one or both of the medications, or
leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Metformin. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should take Metformin.

Alcohol intake: Anyone taking metformin should avoid excessive alcohol intake.

Blood sugar control: If you have fever, trauma, infection, or surgery, you may have a temporary loss of blood sugar control. At such times, your doctor may think it is necessary to stop metformin and temporarily inject insulin. Metformin may be started again after the problem is resolved.

Blood sugar monitoring: Monitor your blood sugar regularly at intervals as discussed with your doctor or diabetes educator.

Diabetes complications: The use of metformin (or any other medication used for diabetes) will not prevent the development of complications particular to diabetes mellitus (e.g., Kidney Disease, nerve disease, eye disease).

Diet: Metformin is a treatment to be taken in combination with a proper diet. Metformin is not a substitute for proper diet.

Dye or contrast agents: If you are going to have an X-ray procedure that uses dye or a contrast agent, you may need to stop taking Metformin for a short time. Contact your doctor for instructions.

Kidney problems: Kidney disease or reduced kidney function causes Metformin to build up in the body, causing side effects. If you have kidney problems, your doctor should closely monitor your condition while you are taking metformin, as it may affect kidney function.

Lactic acidosis: Lactic acidosis is a rare but serious problem that occurs due to metformin accumulation (i.e., the body doesn't get rid of it fast enough) during treatment. If you have severe kidney disease you are at higher risk of developing lactic acidosis. Since alcohol may increase the risk of lactic acidosis, do not drink a lot of alcohol over the short- or long-term while taking Metformin. When it does occur (very rarely), it is fatal in 50% of cases. There have been no reports of lactic acidosis in Canada when metformin was used as directed. If you experience symptoms of lactic acidosis (e.g., weakness, tiredness, drowsiness, unusual muscle pain, trouble breathing, stomach pain with nausea, vomiting or diarrhea, feeling cold, dizziness, light-headedness, or slow or irregular heartbeat), stop taking Metformin and get immediate medical attention.

Liver function: Decreased liver function has been linked to lactic acidosis. Metformin is not recommended for people with severely reduced liver function. If you have moderately reduced liver function, discuss with your doctor how Metformin may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Metformin, and whether any special monitoring is needed.

Low blood sugar: Under usual circumstances, low blood sugar does not occur for people who take only metformin. Low blood sugar could occur when not enough food is eaten, especially when strenuous exercise is undertaken at the same time or when large amounts of alcohol have been consumed.

Reduced response: Over a period of time, you may become progressively less responsive to a particular treatment for diabetes because your diabetes worsens. If metformin fails to lower blood sugar to target levels, talk to your doctor. Your doctor may want to stop metformin or recommend another medication.

Surgery: Metformin should be stopped temporarily for surgery (except for minor surgery where food and fluid intake is not restricted). You will be restarted on Metformin once you are eating and drinking and your kidney function has been tested and is normal. Talk to your doctor for specific instructions.

Vitamin B12 levels: Metformin may decrease vitamin B12 levels. Your doctor will monitor your B12 levels with blood tests while you are taking Metformin.

Pregnancy: Metformin should not be used during pregnancy. If you become pregnant while taking Metformin, contact your doctor immediately.

Breast-feeding: Metformin is believed to pass into breast milk. Metformin should not be used if you are breast-feeding.

Children: The safety and effectiveness of Metformin have not been established for children.

Seniors: Kidney function often decreases with age. As a result, seniors may be more likely to experience side effects of Metformin.

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All material © 1996-2025 MediResource Inc. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health providers with any questions you may have regarding a medical condition.

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