Metformin Medication Guide

How Metformin Works

Metformin is prescription medication that has been shown to promote weight loss , just how it works remains unclear. Medical researchers have suggested that there are a few ways that metformin might impact weight. One is that the medication can reduce your appetite. This is because metformin increases the body’s sensitivity to hormones such as insulin and leptin. Leptin is in charge of telling your body when it is full and should stop eating, so increased sensitivity to this hormone can result in you feeling less hungry. 

Additionally, research suggests that metformin may increase secretion of the GLP-1 hormone, which suppresses appetite and can cause weight loss. In fact, a GLP-1 receptor agonist medication that targets this hormone specifically, semaglutide (Wegovy), is currently FDA approved to treat obesity as well as type 2 diabetes. 

Metformin may also reduce weight by decreasing the amount of visceral fat in the liver and muscle tissue. Visceral fat is stored within the abdominal cavity, which contains several internal organs, including the liver, stomach, and intestines. It can also build up in muscles including the heart muscle. Visceral fat is considered more dangerous than subcutaneous fat because it is associated with an increased risk of various health conditions, such as heart disease.

Metformin Dosing and Storage Instructions

How To Take Metformin

You should take Metformin exactly as your doctor tells you to. Metformin dosing should be increased slowly according to the dosing schedule below.
Starting: Week 1
Week 2
Week 3
Week 4 Onward
  • Take each dose of metformin with a meal to reduce the likelihood of an upset stomach.
  • Metformin Extended Release (ER) tablets should be taken whole. Do not cut, chew or crush your Metformin ER tablets.
  • Please let all of your providers know you are taking metformin.

What If I Miss a Dose of Metformin?

If you miss a dose of Metformin (which could be 1 or 2 tablets), skip that dose and take your next dose at your regularly scheduled time. You should not add the tablets you missed to your next dose. Only one dose of Metformin should be taken at a time.

How To Store Your Metformin Tablets

  • Keep this medication in the container it came in, tightly closed, and out of reach of children. 
  • Store it at room temperature and away from light, excess heat, and moisture (not in the bathroom).

When Should I Stop Taking Metformin?

  • At the beginning of the Sunrise program, you communicate your goal weight to your Sunrise physician. If you achieve your goal weight or achieve a body mass index (BMI) less than 27, you should stop taking Metformin. 
  • You should stop taking Metformin if you, or your family member, are experiencing any of these severe side effects (more information).

Refilling Your Prescription &
Communicating with Your Sunrise Physician

How To Refill Your Metformin Prescription

For the first month of the Sunrise program, you will titrate the dose of Metformin per the instructions on the medication. After several weeks you will check in with your physician and if appropriate, a prescription for several more months will be placed. During this check-in, your physician will evaluate your weight-loss progress and determine whether it is safe to prescribe a refill of Metformin.

You should initiate your first month check-in with your physician once you start Week 3 of your current fill of Metformin. You can message your physician through the Sunrise messaging portal. When you message your physician, please share the following information:

  1. Have you experienced any major side effects that you are concerned about (Yes/No, and if Yes, please explain)?
  2. Have you had any changes to your medical history (Yes/No, and if Yes, please explain)?

When You Should Message Your Sunrise Physician

You are able to message your physician at any time through the Sunrise messaging portal. In addition, below are specific times you should reach out to your Sunrise physician:

Additional Metformin FAQs

What do I need to tell my doctor BEFORE I take this drug?

  • If you are allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
  • If you have any of these health problems: Acidic blood problem, kidney disease, or liver disease.
  • If you have had a recent heart attack or stroke.
  • If you are not able to eat or drink like normal, including before certain procedures or surgery.
  • If you are having an exam or test with contrast or have had one within the past 48 hours, talk with your doctor.

This is not a list of all drugs or health problems that interact with this drug. Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this drug with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

Are there any warnings for the drug?

  • Rarely, metformin may cause too much lactic acid in the blood (lactic acidosis). The risk is higher in people who have kidney problems, liver problems, heart failure, use alcohol, or take other drugs like topiramate. The risk is also higher in people who are 65 or older and in people who are having surgery, an exam or test with contrast, or other procedures. If lactic acidosis happens, it can lead to other health problems and can be deadly. Kidney tests may be done while taking this drug.
  • Do not take this drug if you have a very bad infection, low oxygen, or a lot of fluid loss (dehydration).
  • Call your doctor right away if you have signs of too much lactic acid in the blood (lactic acidosis) like confusion; fast breathing; fast or slow heartbeat; a heartbeat that does not feel normal; very bad stomach pain, upset stomach, or throwing up; feeling very sleepy; shortness of breath; feeling very tired or weak; very bad dizziness; feeling cold; or muscle pain or cramps.

What Are the Serious Side Effects of Metformin?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • It is common to have stomach problems like upset stomach, throwing up, or diarrhea when you start taking this drug. If you have stomach problems later during treatment, call your doctor right away. This may be a sign of an acid health problem in the blood (lactic acidosis).
  • Low blood sugar can happen. The chance may be raised when this drug is used with other drugs for diabetes. Signs may be dizziness, headache, feeling sleepy or weak, shaking, fast heartbeat, confusion, hunger, or sweating. Call your doctor right away if you have any of these signs. Follow what you have been told to do for low blood sugar. This may include taking glucose tablets, liquid glucose, or some fruit juices.
  • Visit the Metformin Full Prescribing Information to learn more about the possible side effects of Metformin.

What Are the Common Side Effects of Metformin?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Stomach pain or heartburn.
  • Gas.
  • Diarrhea, upset stomach, or throwing up.
  • Feeling tired or weak.
  • Headache.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to your national health agency.

Visit the Metformin Full Prescribing Information to learn more about the possible side effects of Metformin.

Who Should Not Take Metformin?

You should not take metformin if:

  • You have are allergic her hypersensitive to metformin or any component of the formulation
  • Kidney disease or dysfunction
  • Unstable and/or insulin-dependent (type 1) diabetes mellitus
  • History of ketoacidosis with or without coma; history of lactic acidosis (regardless of precipitating factors)
  • Excessive alcohol intake (acute or chronic)
  • Severe liver disease 
  • Patients who have had bariatric surgery
  • Pregnancy; breastfeeding
  • You are planing to have a surgical procedures: Metformin-containing products should be withheld the day of surgery; restart after renal function is stable (ADA 2022).

I’ve heard metformin is only for diabetes.  Is that true?

If you have type 2 diabetes or pre-diabetes and are overweight or have obesity, a doctor may prescribe metformin to help you manage your diabetes or lower your risk of developing it.

In fact, a doctor might prescribe metformin for weight loss even if you don’t have diabetes or pre-diabetes. This is an off-label use.
Off label means that the FDA hasn’t approved a drug for a specific use, which in this instance is as a weight loss aid. As a result, there’s less information about how effective it is for this purpose.

Additional Online Resources

Last Updated: 07/29/2023

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