Metformin is likely one of the most prescribed medicines on the planet, with greater than 150 million individuals at present taking it for sort 2 diabetes administration (and, in some instances, weight reduction).
Whereas it’s usually nicely tolerated, like all medicines, it could actually have unwanted effects.
On this article, we’ll take a look at how metformin works; its widespread, unusual, and severe unwanted effects; and tips on how to alleviate these unwanted effects.
How metformin works
Metformin (model names Glucophage, Glucophage XR, Fortamet, Glumetza, and Riomet, plus numerous generics) works by decreasing the quantity of sugar the liver releases all through the day and rising 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 unwanted effects of metformin
The most typical unwanted effects of metformin embody:
- Diarrhea (various from delicate to extreme)
- Flatulence (passing gasoline)
- 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 widespread aspect impact of metformin is weight reduction. Though the drugs is just not FDA-approved for this use, it’s often prescribed off-label for this goal. Within the Diabetes Prevention Program (DPP) Examine, common weight reduction amongst metformin customers was roughly 4.4 to six.6 kilos over two to 3 years.
See extra in: Metformin and Weight Loss: Can a Capsule Assist You Lose Weight?
Meals to keep away from whereas taking metformin
Consultants don’t particularly suggest avoiding any explicit meals whereas taking metformin to stop gastrointestinal unwanted effects comparable to diarrhea.
That mentioned, there are specific meals and drinks that may improve the chance of those points typically, so chances are you’ll need to cut back your consumption of them if you’re experiencing gastrointestinal discomfort with metformin. These embody:
- Sugar
- Synthetic sweeteners
- Dairy merchandise
- Garlic, onions, and different meals excessive in FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols — sure sugars which can be 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 modifications may assist handle gastrointestinal signs comparable to diarrhea whereas taking metformin.
Study extra in: Can Metformin Trigger Diarrhea? and Meals to Keep away from Whereas Taking Metformin.
How lengthy after taking metformin do unwanted effects begin?
Metformin’s unwanted effects often seem rapidly after the primary dose, and whereas they enhance for some individuals after a couple of weeks, others could discover they persist.
Others could not even start to expertise unwanted effects till they’ve been taking the drug for months or a yr.
Unusual (severe) unwanted effects of metformin
Vitamin B12 deficiency
Latest analysis has proven that long-term use of metformin can lead to vitamin B12 deficiency in some individuals. Signs of vitamin B12 deficiency can embody:
- Anemia
- Irritation of the tongue
- Fatigue
- Palpitations
- Pale pores and skin
- Dementia
- Weight reduction
- Infertility
Left untreated, B12 deficiency could cause vital nerve injury, finally 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 truth be a aspect impact of the B12 deficiency brought on by metformin.
This nerve injury is irreversible, however additional injury might be prevented by supplementing with an everyday 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 beneficial in some instances.)
Lactic acidosis
There have been a big variety of research on metformin’s danger of inflicting lactic acidosis — a probably deadly situation through which lactic acid builds up within the physique. Signs of lactic acidosis can embody:
- 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 mentioned, 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 p.c) had adequate knowledge to help 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 embody individuals with circumstances comparable 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 not often causes hypoglycemia in individuals with diabetes who’re not taking insulin injections, as a result of it doesn’t improve insulin manufacturing like many different diabetes medicines.
Name your physician when you’ve got any signs of hypoglycemia, which may embody:
- Weak spot
- Tiredness
- Nausea
- Vomiting
- Abdomen ache
- Dizziness
- Lightheadedness
- Abnormally quick or sluggish heartbeat
“Faux” low blood sugar
Whereas this isn’t a damaging aspect impact, it’s an vital state of affairs to pay attention to when beginning on metformin.
If you drop your blood sugars to a “regular” vary after working persistently excessive for some time, chances are you’ll expertise “faux” signs of low blood sugar.
As a result of your physique has grow to be used to excessive blood sugars, returning to regular ranges could make you’re feeling dizzy, lightheaded, nauseous, and very hungry.
This could go after a couple of days to weeks as your physique adjusts to your new regular blood sugar ranges.
When 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 under 70 mg/dl) that requires therapy with glucose.
Allergic reactions to metformin
Allergic reactions to metformin are uncommon, however they do occur. Signs of an allergic response can embody:
- Rash
- Hives
- Itching
- Swelling of the face, lips, or tongue
- Issue respiration
When you expertise any of those signs, search medical consideration instantly.
Lowering metformin unwanted effects
Happily, there are some things you are able to do to alleviate, reduce, or altogether stop the unwanted 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 consuming your meal, slightly than earlier than you begin consuming.
Folks 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 an especially small dose, as a substitute of the complete dose your physician would usually prescribe in your top and weight, you could possibly drastically cut back these initially uncomfortable unwanted effects.
If that is an method you’d prefer to attempt, discuss to your physician about adjusting your doses in an effort 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 with no consideration for the extended-release (ER or XR) model.
When utilizing the ER/XR model of metformin, the remedy is progressively 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 unwanted effects of metformin.
Nevertheless, chances are you’ll 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 fitting remedy for you. Then they are going to be extra more likely to cowl the extended-release model.
Take your dose complete
It will be significant to not crush, break, or chew your metformin tablets, as doing so might trigger them to be absorbed extra rapidly and improve the chance of unwanted effects.
Mix it with different diabetes medicines
In case your healthcare supplier intends to begin you on a GLP-1 drug, the unwanted effects of metformin can truly assist counterbalance the constipating unwanted effects of most of the medicines on this class.
GLP-1 medicines for diabetes at present accessible in the USA embody the next:
- Dulaglutide (model title 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 unwanted effects could assist primarily steadiness one another out.
Learn extra in: Metformin Mixture Medicine for Kind 2 Diabetes.
Strive one thing else
There are some individuals who merely don’t tolerate metformin. When you discover you can not bear the unwanted effects, discuss to your healthcare crew.
When you select to cease taking metformin, they will help you discover a totally different sort of diabetes remedy to handle your blood sugar ranges.
Learn extra in: Stopping Metformin: When and How You Can Cease Taking Metformin and The Finest Options to Metformin for Kind 2 Diabetes Administration.
Who ought to keep away from taking metformin?
As with all medicines, there are specific individuals who shouldn’t take metformin.
The first concern with metformin facilities on its potential to extend the chance of extreme lactic acid manufacturing. Successfully eradicating lactic acid from the physique requires correct functioning of the organs.
If in case you have been recognized with kidney or liver points:
Your liver and your kidneys each play a essential position in clearing metformin out of your physique. If in case you have extreme kidney or liver illness, you shouldn’t take metformin.
That mentioned, latest tips have grow to be extra permissive relative to kidney illness, recognizing that metformin might be protected to be used in individuals with delicate to average continual kidney illness (CKD) below sure circumstances.
If in case you have delicate to average CKD, converse along with your physician about whether or not metformin use is protected in your state of affairs.
If in case 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 general kidney perform.
As a result of the kidneys play an important position in clearing metformin out of your physique, individuals with a historical past of coronary heart points shouldn’t take metformin.
When you drink alcohol typically or in giant portions:
Provided that metformin’s effectiveness is determined by wholesome liver and kidney perform, common heavy alcohol consumption can heighten the chance of issues when taking metformin.
Learn extra: Metformin & Alcohol: Can You Drink Whereas Taking Metformin?
If you’ll be having surgical procedure or an imaging check:
Lack of fluid and meals previous to surgical procedure can improve the burden on the kidneys and lift the chance of hypertension. And the distinction dyes utilized in sure imaging exams comparable to MRIs can work together with metformin and trigger a drop in kidney perform.
Converse along with your physician about tips on how to deal with your metformin routine if you’ll be having one in all these procedures.
Study extra in: Is Metformin Secure?
Last ideas
Whereas metformin is usually nicely tolerated, it could actually have unwanted effects similar to any remedy.
The most typical unwanted effects are delicate and gastrointestinal in nature, however extra severe unwanted effects comparable to vitamin B12 deficiency and lactic acidosis can happen.
When you expertise any signs whereas taking metformin, discuss to your physician about adjusting your dose, switching to extended-release tablets, or attempting a unique remedy.
When you expertise any severe or life-threatening signs, search medical consideration instantly.
Recommended subsequent article: All the pieces You Have to Know About Metformin.
