Metformin is among the most prescribed medicines on the planet, with greater than 150 million folks at the moment taking it for kind 2 diabetes administration (and, in some instances, weight reduction).
Whereas it’s usually effectively tolerated, like all drugs, it will possibly have negative effects.
On this article, we’ll take a look at how metformin works; its frequent, unusual, and severe negative effects; and the way to alleviate these negative effects.
Desk of Contents
How metformin works
Metformin (model names Glucophage, Glucophage XR, Fortamet, Glumetza, and Riomet, plus varied generics) works by lowering the quantity of sugar the liver releases all through the day and growing the physique’s sensitivity to insulin.
It additionally reduces the quantity of glucose (sugar) that’s absorbed from the meals you eat, which in flip reduces your blood sugar ranges after consuming.
Widespread negative effects of metformin
The commonest negative effects of metformin embrace:
- Diarrhea (various from delicate to extreme)
- Flatulence (passing fuel)
- Nausea or vomiting
- Bloating and constipation
- Abdomen discomfort
- Heartburn
- Headache
- Decreased urge for food and weight reduction
- Muscle ache or cramping
- A metallic style within the mouth
One other frequent facet impact of metformin is weight reduction. Though the drugs shouldn’t be FDA-approved for this use, it’s continuously prescribed off-label for this function. Within the Diabetes Prevention Program (DPP) Examine, common weight reduction amongst metformin customers was roughly 4.4 to six.6 kilos over two to a few years.
See extra in: Metformin and Weight Loss: Can a Tablet Assist You Lose Weight?
Meals to keep away from whereas taking metformin
Consultants don’t particularly advocate avoiding any specific meals whereas taking metformin to stop gastrointestinal negative effects equivalent to diarrhea.
That stated, there are particular meals and drinks that may enhance the danger of those points normally, so you could need to cut back your consumption of them in case you are experiencing gastrointestinal discomfort with metformin. These embrace:
- Sugar
- Synthetic sweeteners
- Dairy merchandise
- Garlic, onions, and different meals excessive in FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols — sure sugars which are poorly absorbed and should trigger intestinal misery)
- Fructose (a pure sugar present in fruit)
- Gluten (a protein present in wheat, rye, barley, and their hybrids)
- Fried or fatty meals
- Spicy meals
- Alcohol
- Caffeine
These adjustments would possibly assist handle gastrointestinal signs equivalent to diarrhea whereas taking metformin.
Be taught extra in: Can Metformin Trigger Diarrhea? and Meals to Keep away from Whereas Taking Metformin.
How lengthy after taking metformin do negative effects begin?
Metformin’s negative effects often seem rapidly after the primary dose, and whereas they enhance for some folks after a couple of weeks, others could discover they persist.
Others could not even start to expertise negative effects till they’ve been taking the drug for months or a 12 months.
Unusual (severe) negative effects of metformin
Vitamin B12 deficiency
Latest analysis has proven that long-term use of metformin may end up in vitamin B12 deficiency in some folks. Signs of vitamin B12 deficiency can embrace:
- Anemia
- Irritation of the tongue
- Fatigue
- Palpitations
- Pale pores and skin
- Dementia
- Weight reduction
- Infertility
Left untreated, B12 deficiency could cause vital nerve harm, in the end resulting in a analysis of peripheral neuropathy.
If a health care provider isn’t conscious of this danger, they may misdiagnose the reason for an individual’s neuropathy as being the results of excessive blood sugar ranges when it might in actual fact be a facet impact of the B12 deficiency brought on by metformin.
This nerve harm is irreversible, however additional harm might be prevented by supplementing with a daily dose of vitamin B12.
Everybody taking metformin ought to have their B12 ranges examined yearly. In session with their healthcare supplier, anybody with insufficient ranges ought to begin taking a B12 complement instantly. (Vitamin B12 injections each few months could also be advisable in some instances.)
Lactic acidosis
There have been a major variety of research on metformin’s danger of inflicting lactic acidosis — a doubtlessly deadly situation during which lactic acid builds up within the physique. Signs of lactic acidosis can embrace:
- Nausea
- Vomiting
- Weak spot
- Fatigue
- Quick, deep respiration
- Muscle cramps and physique aches
Metformin comes with a “black field” warning about this danger, essentially the most extreme warning that the U.S. Meals and Drug Administration (FDA) points.
That stated, a large-scale research reported in 2022 examined 4,241 instances of suspected metformin-associated lactic acidosis and located that solely a small fraction (9 %) had adequate information to assist such a analysis, underscoring the rarity of this situation.
Nearly all instances of lactic acidosis from metformin use are outcomes of overdoses — not regular use of the drug.
These most liable to growing lactic acidosis whereas on metformin embrace folks with circumstances equivalent to kidney or liver points, a historical past of coronary heart assaults or acute coronary heart failure, and frequent alcohol shoppers.
See extra in: Can Metformin Trigger Lactic Acidosis?
Hypoglycemia (low blood sugar)
Metformin solely very hardly ever causes hypoglycemia in folks with diabetes who’re not taking insulin injections, as a result of it doesn’t enhance insulin manufacturing like many different diabetes drugs.
Name your physician you probably have any signs of hypoglycemia, which may embrace:
- Weak spot
- Tiredness
- Nausea
- Vomiting
- Abdomen ache
- Dizziness
- Lightheadedness
- Abnormally quick or sluggish heartbeat
“Pretend” low blood sugar
Whereas this isn’t a damaging facet impact, it’s an necessary scenario to concentrate on when beginning on metformin.
While you drop your blood sugars to a “regular” vary after operating constantly excessive for some time, you could expertise “faux” signs of low blood sugar.
As a result of your physique has turn out to be used to excessive blood sugars, returning to regular ranges could make you are feeling dizzy, lightheaded, nauseous, and very hungry.
This could move after a couple of days to weeks as your physique adjusts to your new regular blood sugar ranges.
Should you’re feeling low, at all times examine your blood sugar to ensure you aren’t experiencing an actual low blood sugar (usually thought of to be beneath 70 mg/dl) that requires remedy with glucose.
Allergic reactions to metformin
Allergic reactions to metformin are uncommon, however they do occur. Signs of an allergic response can embrace:
- Rash
- Hives
- Itching
- Swelling of the face, lips, or tongue
- Problem respiration
Should you expertise any of those signs, search medical consideration instantly.
Decreasing metformin negative effects
Fortuitously, there are some things you are able to do to alleviate, reduce, or altogether forestall the negative effects brought on by metformin.
Take your dose throughout your meal, not earlier than
One key step is to take your metformin dose midway by way of consuming your meal, relatively than earlier than you begin consuming.
Individuals taking the drugs report far much less abdomen misery if there’s already meals of their abdomen by the point their metformin dose is being digested.
Begin with a really small dose
By beginning with a particularly small dose, as a substitute of the total dose your physician would usually prescribe on your top and weight, you might be able to drastically cut back these initially uncomfortable negative effects.
If that is an method you’d wish to attempt, discuss to your physician about adjusting your doses with the intention to give your physique time to acclimate to the drug.
Learn extra in: Metformin Dosage Information (Min and Max Doses).
Ask for the “extended-release” model
Too typically, docs prescribe the common (standard- or immediate-release) model as a right for the extended-release (ER or XR) model.
When utilizing the ER/XR model of metformin, the treatment is regularly launched over a number of hours as a substitute of instantly. This course of successfully lessens the undesirable gastrointestinal signs.
Though it might be costlier, this method can considerably lower the general negative effects of metformin.
Nonetheless, you could must attempt the common model first. That is so your physician can inform your insurance coverage firm that you just tried it and it wasn’t the suitable treatment for you. Then they are going to be extra prone to cowl the extended-release model.
Take your dose complete
It is crucial to not crush, break, or chew your metformin tablets, as doing so might trigger them to be absorbed extra rapidly and enhance the danger of negative effects.
Mix it with different diabetes drugs
In case your healthcare supplier intends to start out you on a GLP-1 drug, the negative effects of metformin can really assist counterbalance the constipating negative effects of most of the medicines on this class.
GLP-1 drugs for diabetes at the moment obtainable in the USA embrace the next:
- Dulaglutide (model identify Trulicity)
- Exenatide (Byetta)
- Exenatide prolonged launch (Bydureon bcise)
- Liraglutide (Victoza, Saxenda)
- Lixisenatide (Adlyxin)
- Semaglutide (Ozempic, Rybelsus)
By together with each varieties of medicine in your diabetes administration plan, the negative effects could assist basically steadiness one another out.
Learn extra in: Metformin Mixture Medicine for Kind 2 Diabetes.
Attempt one thing else
There are some individuals who merely don’t tolerate metformin. Should you discover you can not bear the negative effects, discuss to your healthcare group.
Should you select to cease taking metformin, they might help you discover a completely different kind of diabetes treatment to handle your blood sugar ranges.
Learn extra in: Stopping Metformin: When and How You Can Cease Taking Metformin and The Finest Alternate options to Metformin for Kind 2 Diabetes Administration.
Who ought to keep away from taking metformin?
As with all drugs, there are particular individuals who shouldn’t take metformin.
The first concern with metformin facilities on its potential to extend the danger of extreme lactic acid manufacturing. Successfully eradicating lactic acid from the physique requires correct functioning of the organs.
When you have been recognized with kidney or liver points:
Your liver and your kidneys each play a vital position in clearing metformin out of your physique. When you have extreme kidney or liver illness, you shouldn’t take metformin.
That stated, current tips have turn out to be extra permissive relative to kidney illness, recognizing that metformin might be protected to be used in folks with delicate to average continual kidney illness (CKD) beneath sure circumstances.
When you have delicate to average CKD, communicate together with your physician about whether or not metformin use is protected in your scenario.
When you have had a coronary heart assault or acute coronary heart failure:
Severe coronary heart circumstances can have an effect on how a lot blood is pumped to your kidneys, which may cut back your total kidney operate.
As a result of the kidneys play an important position in clearing metformin out of your physique, folks with a historical past of coronary heart points mustn’t take metformin.
Should you drink alcohol typically or in giant portions:
Provided that metformin’s effectiveness is determined by wholesome liver and kidney operate, common heavy alcohol consumption can heighten the danger of issues when taking metformin.
Learn extra: Metformin & Alcohol: Can You Drink Whereas Taking Metformin?
If you may be having surgical procedure or an imaging check:
Lack of fluid and meals previous to surgical procedure can enhance the burden on the kidneys and lift the danger of hypertension. And the distinction dyes utilized in sure imaging exams equivalent to MRIs can work together with metformin and trigger a drop in kidney operate.
Converse together with your physician about the way to deal with your metformin routine if you may be having one in all these procedures.
Be taught extra in: Is Metformin Secure?
Ultimate ideas
Whereas metformin is usually effectively tolerated, it will possibly have negative effects similar to any treatment.
The commonest negative effects are delicate and gastrointestinal in nature, however extra severe negative effects equivalent to vitamin B12 deficiency and lactic acidosis can happen.
Should you expertise any signs whereas taking metformin, discuss to your physician about adjusting your dose, switching to extended-release tablets, or attempting a special treatment.
Should you expertise any severe or life-threatening signs, search medical consideration instantly.
Advised subsequent article: The whole lot You Have to Know About Metformin.