Medically reviewed by Jessica Swirble, PharmD
Last updated on 6/6/2024

Drug Information | Side Effects | Use & Dosage | Request a Prescription

The use of metformin can lead to various side effects in some individuals.

Common mild side effects of metformin use include:

• Diarrhea
  
• Gas
  
• Bloating
  
• Nausea
  
• Vomiting
  
• Upset stomach
  
• Indigestion
  
• Weakness
  
• Headache
  
  

More severe side effects include:

• Hypoglycemia (low blood sugar)
  
• Lactic acidosis (lactic acid buildup in the bloodstream)
  
• Chest pain
  
• Vitamin B12 deficiency
  
  

If you experience any severe or concerning side effects while taking metformin, contact your healthcare provider right away.

Tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with metformin. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with metformin.

Tell your provider if you are taking these medications or supplements:

• Other diabetes medications
  
• Diuretics
  
• Corticosteroids
  
• Blood pressure medications
  
• Antipsychotic medications
  
• Hormonal contraceptives
  
• Thyroid medications
  
• Seizure medications
  
• Ranolazine
  
• Tivicay
  
• Cimetidine
  
• Anticoagulants or antiplatelet drugs
  
• Alcohol or medications containing alcohol
  
  

You should also mention medical conditions such as:

• You are over 65 years of age
  
• You have a history of heart attacks or heart disease
  
• You have had a stroke
  
• You have a history of diabetic ketoacidosis
  
• You have a history of liver or kidney disease
  
  

If you are pregnant, planning to become pregnant, or breastfeeding, discuss the potential risks and benefits of using metformin with your healthcare provider.

Take metformin exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment.

Metformin should be taken with a meal.

Your provider may prescribe metformin in conjunction with a reduced-calorie diet and increased physical activity to regulate blood sugar levels.

In case of a metformin overdose, seek medical attention immediately. Symptoms of overdose may include severe tiredness, weakness, slow heart rate, severe dizziness, or fainting. If you suspect an overdose, contact the poison control helpline at 1-800-222-1222 or call emergency services.