The first treatment for type 2 diabetes blood
glucose (sugar) control is often meal planning, weight loss, and exercising.
Sometimes these measures are not enough to
bring blood glucose levels down near the normal range. The next step is taking
a medicine that lowers blood glucose levels.
Only people with type 2 diabetes can
use pills to manage their diabetes, people with type 1 diabetes must
use insulin.
These pills work best when used with meal
planning and exercise. This way you have three therapies working together to
lower your blood glucose levels.
Diabetes pills don't work for everyone.
Although most people find that their blood glucose levels go down when they
begin taking pills, their blood glucose levels may not go near the
normal range.
Will They Help?
What are the chances that diabetes pills will
work for you? Your chances are low if you have had diabetes for more than 10
years or already take more than 20 units of insulin each day. On the other
hand, your chances are good if you developed diabetes recently or have needed
little or no insulin to keep your blood glucose levels near normal.
Diabetes pills sometimes stop working after a
few months or years. The cause is often unknown. This doesn't mean your
diabetes is worse. When this happens, oral combination therapy can
help.
Even if diabetes pills do bring your blood
glucose levels near the normal range, you may still need to take insulin if you
have a severe infection or need surgery. Pills may not be able to control blood
glucose levels during these stressful times when blood glucose levels shoot up.
Also, if you plan to become pregnant, you will
need to control your diabetes with diet and exercise or with insulin. It is not
safe for pregnant women to take oral diabetes medications.
There is no "best" pill or treatment
for type 2 diabetes. You may need to try more than one type of pill,
combination of pills, or pills plus insulin.
There are different types, or classes, of drugs that work in
different ways to lower blood glucose (blood sugar)
levels:
·
Sulfonylureas
·
Biguanides
·
Meglitinides
·
Thiazolidinediones
·
DPP-4 inhibitors
·
SGLT2 Inhibitors
·
Alpha-glucosidase inhibitors
·
Bile Acid Sequestrants
Sulfonylureas
Sulfonylureas
stimulate the beta cells of the pancreas to
release more insulin.
Sulfonylurea drugs have been in use since the 1950s. Chlorpropamide (Diabinese) is the only
first-generation sulfonylurea still in use today. The second generation
sulfonylureas are used in smaller doses than the first-generation drugs. There
are three second-generation drugs: glipizide (Glucotrol
and Glucotrol XL), glyburide (Micronase,
Glynase, and Diabeta), and glimepiride (Amaryl).
These drugs are generally taken one to two times a day, before meals. All sulfonylurea drugs have similar effects on blood glucose levels, but they differ in side effects,
how often they are taken, and interactions with other drugs.
Biguanides
Metformin (Glucophage)
is a biguanide.
Biguanides lower blood glucose levels primarily by decreasing the amount of
glucose produced by the liver. Metformin also helps to lower blood glucose
levels by making muscle tissue more sensitive to insulin so glucose can be
absorbed. It is usually taken two times a day. A side effect of metformin may be diarrhea, but this is improved
when the drug is taken with food.
Meglitinides
Meglitinides are drugs
that also stimulate the beta cells to release insulin. Repaglinide (Prandin) and nateglinide (Starlix) are meglitinides. They are
taken before each of three meals.
Because sulfonylureas
and meglitinides stimulate the release of insulin, it is possible to have hypoglycemia (low blood glucose levels).
You should know that
alcohol and some diabetes pills may not mix. Occasionally, chlorpropamide and
other sulfonylureas, can interact with alcohol to cause vomiting, flushing or
sickness. Ask your doctor if you are concerned about any of these side effects.
Thiazolidinediones
Rosiglitazone
(Avandia) and pioglitazone (ACTOS) are in a group of drugs called
thiazolidinediones. These drugs help insulin work better in the muscle and fat and also reduce glucose production in
the liver. The first drug in this group, troglitazone (Rezulin), was removed
from the market because it caused serious liver problems in a small number of
people. So far rosiglitazone and pioglitazone have
not shown the same problems, but users are still monitored closely for liver
problems as a precaution. Both drugs appear to increase the risk for heart
failure in some individuals, and there is debate about whether rosiglitazone may contribute to an increased risk
for heart attacks. Both drugs are effective at reducing A1C and generally have few side effects.
DPP-4 Inhibitors
A new class of
medications called DPP-4 inhibitors help improve A1C without causing hypoglycemia.
They work by by preventing the breakdown of a naturally occurring compound in
the body, GLP-1. GLP-1 reduces blood glucose levels in the body, but is broken
down very quickly so it does not work well when injected as a drug itself. By
interfering in the process that breaks down GLP-1, DPP-4 inhibitors allow it to
remain active in the body longer, lowering blood glucose levels only when they
are elevated. DPP-4 inhibitors do not tend to cause weight gain and tend to
have a neutral or positive effect on cholesterol levels.
Sitagliptin (Januvia), saxagliptin (Onglyza), linagliptin (Tradjenta),
alogliptin (Nesina) are the DPP-4 inhibitors currently on the market in the US.
SGLT2 Inhibitors
Glucose in the
bloodstream passes through the kidneys, where it can either be excreted or
reabsorbed. Sodium-glucose transporter 2 (SGLT2) works in the kidney to
reabsorb glucose, and a new class of medication, SGLT2 inhibitors, block this
action, causing excess glucose to be eliminated in the urine. Canagliflozin
(Invokana) and dapagliflozin (Farxiga) are SGLT2 inhibitors that have recently
been approved by the FDA to treat type 2 diabetes. Because they increase
glucose levels in the urine, side effects can include urinary tract and
yeast infections.
Alpha-glucosidase
inhibitors
Acarbose (Precose) and miglitol (Glyset) are alpha-glucosidase
inhibitors. These drugs help the body to lower blood glucose levels by blocking
the breakdown of starches, such as bread, potatoes, and pasta in the intestine.
They also slow the breakdown of some sugars, such as table sugar. Their action
slows the rise in blood glucose levels after a meal. They should be taken with
the first bite of a meal. These drugs may have side effects, including gas and
diarrhea.
Bile Acid Sequestrants
The bile acid
sequestrant (BAS) colesevelam (Welchol) is a cholesterol-lowering medication
that also reduces blood glucose levels in patients with diabetes. BASs
help remove cholesterol from the body, particularly LDL cholesterol, which is
often elevated in people with diabetes. The medications reduce LDL cholesterol by binding with bile acids in the
digestive system; the body in turn uses cholesterol to replace the bile acids,
which lowers cholesterol levels. The mechanism by which colesevelam lowers glucose
levels is not well understood. Because BASs are not absorbed into the
bloodstream, they are usually safe for use by patients who may not be able to
use other medications because of liver problems. Because of the way they work,
side effects of BASs can include flatulence and constipation.
Oral combination
therapy
Because the drugs
listed above act in different ways to lower blood glucose levels, they may be
used together. For example, a biguanide and a sulfonylurea may be used
together. Many combinations can be used. Though taking more than one drug can
be more costly and can increase the risk of side effects, combining oral
medications can improve blood glucose control when taking only a single pill
does not have the desired effects. Switching from one single pill to another is
not as effective as adding another type of diabetes medicine.