Oral Medicines for Type 2 Diabetes

Type of diabetes pills

Biguanides

These pills help control the amount of sugar in your blood. They decrease the amount of sugar your liver makes. This medicine does not cause your pancreas to make insulin. It helps your body use insulin better. You often take these pills with or after each meal. Possible side effects include:

• Diarrhea

• Nausea

• Vomiting

• Belly bloating

• A lot of gas

• Metallic taste in mouth

• Lower blood vitamin B12 levels from decreased absorption from the gastrointestinal tract of this vitamin

Have your vitamin B-12 levels checked often if you use these pills for a long time. This is even more important if you have anemia or peripheral neuropathy.

Sulfonylureas

These pills help your pancreas make more insulin. Take them 30 minutes before a meal. Don't take this medicine if you're allergic to sulfa medicines. Possible side effects include:

• Low blood sugar

• Weight gain

• Low levels of sodium in the blood

Alpha-glucosidase inhibitors

These pills slow the digestion of sugars and starches. They can help keep your blood sugar from going too high after a meal. Take them with the first bite of each main meal. Possible side effects include:

• Stomach bloating

• Nausea

• Diarrhea

• A lot of gas

Thiazolidinediones

These pills help your body respond better to insulin. You may need lab tests to check your liver before these pills are prescribed. Your liver will be checked often while you're taking them. Possible side effects include: 

• Weight gain

• Extra fluid in your body and swelling

• Higher risk for heart failure

• Brittle bones (osteoporosis) and higher risk for broken bones (fractures)

• Increase in LDL (bad) cholesterol

Meglitinides

These pills stimulate your pancreas to increase your insulin for a short time. Take them before meals. Possible side effects include:

• Low blood sugar

• Diarrhea

• Headache 

• Slightly raised risk for heart problems

DPP-4 inhibitors

These pills help lower blood sugar levels. They are less likely to cause low blood sugar. But they may cause low blood sugar if taken with a sulfonylurea or insulin. You take them once a day. Possible side effects include:

• Upper respiratory tract infection

• Stuffy or runny nose

• Sore throat

• Headache

Other side effects are under study.

SGLT-2 inhibitors

These pills help lower blood sugar levels in people with type 2 diabetes. They remove excess sugar from your body. They do this by sending the sugar out through your kidneys. Possible side effects include:

• Urinary tract infections

• Genital fungal infections, especially in women

• Fluid loss (dehydration)

• Low blood pressure

• Increased risk of broken bones

• Ketoacidosis while blood sugar is only mildly raised above target range

The FDA has issued a safety warning for the SGLT-2 inhibitor canagliflozin. Recent studies have shown that this medicine increases the risk of leg and foot amputations. When taking this medicine, tell your provider right away if you have any new pain or soreness, sores (ulcers), or infections in your legs or feet. Talk with your provider before stopping any diabetes medicine. 

Medicines of this class may also sometimes increase the risk of bone fracture. They must be used with caution if your kidneys aren't working well.

Dopamine D2 receptor agonist (bromocriptine mesylate)

These pills help lower blood sugar levels in people with type 2 diabetes. Possible side effects include:

• Nausea

• Vomiting

• Feeling tired and weak (fatigue)

• Dizziness

• Headaches

GLP-1 receptor agonists

These medicines are mainly given as shots (injections). But at least 1 of these is now offered as a pill. It is taken before breakfast. It works by increasing the amount of insulin your pancreas puts out when you eat. It shouldn't cause low blood sugar, unless it's used with insulin or sulfonylurea medicines.

Possible side effects of this class of medicine include:

• Nausea, vomiting, or diarrhea

• Pancreatitis

• A possible increased risk of a certain rare form of thyroid tumor (seen in studies in other animals)

Combination pills

These medicines may help keep your blood sugar in your target range. They also help your pancreas make more insulin. And they may help your muscles use insulin better. Side effects depend on which type of combination you use. Your provider can tell you more.

Watch for symptoms of low blood sugar

Symptoms include:

• Headaches

• Shakiness or dizziness

• Hunger

• Cold, clammy skin

• Sweating

• A hard, fast heartbeat

• Confusion or grouchiness

If you think your blood sugar is low, check a blood sample with a meter. If the level is low, eat 1 of the quick-fix foods below. They can help raise your blood sugar quickly:

• 3 to 4 glucose tablets

• 1 serving of glucose gel

• 1/2 cup (4 ounces) of any fruit juice

• 1/2 cup (4 ounces) of regular (not diet) soda

• 1 tbsp of honey or sugar

• 5 to 6 pieces of hard candy

Recheck your blood sugar in 15 minutes. If it's still low, eat another serving. If it stays low after the second snack, get medical care.