From the Parish Nurse – July 2019
What to Know About Metformin
By Amy Campbell, MS, RD, LDN, CDE
While there are a growing number of classes of drugs to help
treat Type 2 diabetes, most clinical guidelines suggest that
metformin be prescribed first, as it’s safe, effective and
inexpensive. In addition, metformin may provide other health
benefits besides helping to lower blood sugar. Not everyone
understands how it works, and there are many unfounded claims
that this drug is dangerous. There are risks to taking any drug,
and while metformin isn’t for everyone, there’s a lot about this
drug that’s helpful and important to know.
Metformin has been around for a long time.
Metformin contains a substance called guanidine, which can
lower blood sugars. Guanidine is found in an herb called goat’s
rue (also known as French lilac), and his herb has been used to
treat diabetes since the early 1900s, although it’s been used in
the UK since 1958.
Metformin can treat prediabetes.
About 84 million people in the U.S. have prediabetes; without
intervention, about 70 percent of them will go on to develop
Type 2 diabetes. The Diabetes Prevention Program (DPP), a
landmark clinical trial, showed that lifestyle changes (weight loss,
healthy eating, physical activity) can lower the risk of getting
Type 2 diabetes by close to 60 percent. It also showed that taking
metformin can lower the risk by 31 percent. Data from the
ongoing DPP study indicates that lifestyle changes or metformin
could reduce or delay the onset of Type 2 diabetes by up to 15
years.
There are different ways to take metformin.
Metformin comes in tablet form that is typically taken once or
twice a day. It’s also available as an extended-release tablet that
is taken once a day. A liquid form of metformin, called Riomet, is
an option if swallowing pills isn’t for you. Metformin is available
as a generic drug (making this very affordable), but the brandname versions include Glucophage, Glucophage XR, Glumetza,
Fortamet and Riomet. In addition, metformin is available in
combination with other types of diabetes medicines.
Metformin is linked to vitamin B12 deficiency.
Vitamin B12 is needed for optimal brain and nervous system
function. Taking metformin for an extended period of time raises
the risk of developing a B12 deficiency. Metformin appears to
limit the absorption of B12 in the stomach and from the
bloodstream into cells. A B12 deficiency can lead to
megaloblastic anemia, neuropathy, memory loss and fatigue. If
you take metformin, check with your doctor about getting your
B12 checked and whether you may need to supplement with
B12.
Metformin is used to treat PCOS.
PCOS (polycystic ovary syndrome) is a hormonal disorder that
affects women of childbearing age. Symptoms include irregular
menstrual periods, an excess of androgen (a male hormone) and
numerous cysts on the ovaries. PCOS is also associated with
obesity, hirsutism (excessive body hair growth), difficulty
becoming pregnant and insulin resistance. Hormones may be
prescribed to help regulate the menstrual cycle and encourage
ovulation. Lifestyle changes, such as losing weight and being
physically active, can help. In addition, metformin may be
prescribed to improve insulin resistance, which not only
decreases the risk of Type 2 diabetes but also helps to balance
hormone levels, helping to regulate menstruation and ovulation.
You may need to stop taking metformin before having a test that
uses contrast dye.
If you take metformin and are due to have a computerized
tomography (CT) scan, magnetic resonance imaging (MRI) or
angiogram that involves the use of intravenous therapy (IV)
contrast dye, talk with your doctor about stopping your
metformin before the procedure. The contrast dye may cause
minor, short-term changes to your kidney function. According to
the American College of Radiology, you may not need to stop
taking metformin if you have normal kidney function. However, if
you have acute or chronic kidney issues, you will likely need to
stop taking your metformin prior to the procedure and 48 hours
afterwards.
Metformin may help with weight loss.
Metformin isn’t a weight-loss drug. But studies show that some
people who take this medicine lose weight-as long as they are
eating healthfully and being active. Weight loss may result from a
reduced appetite. Metformin may also affect how the body
stores fat. And metformin lowers insulin resistance, which can
make it easier to lose weight. On a side note, metformin is
sometimes prescribed to people who take antipsychotic
medicines to prevent or reduce weight gain.
Metformin helps to reduce heart disease deaths in those with
Type 2 diabetes.
A major complication of diabetes is heart disease. Research on
more than one million people with diabetes shows that
metformin can reduce the risk of dying from heart disease by 30
to 40 percent compared with sulfonylurea drugs (another class of
diabetes pills). Results from a newer study, called REMOVAL,
showed that metformin lowered LDL cholesterol, plaque
accumulation and weight in more than 400 people with Type 1
diabetes, indication that this drug may be helpful for preventing
heart disease in those with Type 1 diabetes.
Metformin sometimes has an unpleasant smell.
It’s understandable that if your medicine smells like dead fish, it’s
going to be hard to swallow. Apparently, generic metformin has a
higher likelihood of smelling bad. If you notice a bad smell when
you open your metformin container, you can try a couple of
things: hold your nose when you take it or talk to your doctor
about switching to another type of metformin, including an
extended-release version.
There are definitely pros and cons to taking metformin. Talk with
your doctor or diabetes educator if you have concerns or
questions about this drug and find out if it’s a good choice for
you.