Type 2 Diabetes Medications: A Guide to Drugs & Treatment Options

Medication Options for Type 2 Diabetes Evolve Beyond Metformin

For many years, metformin was the standard first-line medication for individuals newly diagnosed with type 2 diabetes. However, a shift is occurring in treatment approaches, with many endocrinologists now prioritizing other medications as initial therapies. While metformin remains a viable option, particularly as recommended by the American Diabetes Association (ADA) for some high-risk adults with prediabetes, newer classes of drugs are gaining prominence due to their broader health benefits.

“While primary care physicians may still follow the old idea that metformin is ‘first line,’ I think most endocrinologists have been using GLP-1 receptor agonists and SGLT2 inhibitors as best-in-class therapy for nearly a decade,” explains Dr. Michael Uzmann, a board-certified endocrinologist and internist at A1Endocrinology in Las Vegas.

This change in perspective is driven by a growing understanding of the interconnectedness of diabetes with other health conditions, particularly kidney and heart disease. Dr. Menachem Jacobs, medical co-founder at Outlive Biology and a resident physician at Yale New Haven Hospital, emphasizes this shift. “Recently… I shifted my strategy. I am now making it my top priority to safeguard the kidneys and heart right away,” he says. “My go-to medications for patients with renal disease or heart failure are SGLT2 inhibitors or GLP-1 agonists. Organs are really saved by them.”

Biguanides: The Established Option

Metformin is the sole drug in the biguanide class currently available in the United States. It functions by reducing glucose production in the liver and improving the body’s response to insulin. Common side effects include nausea, diarrhea, and vomiting, which can often be mitigated by taking the medication with food. However, metformin is not suitable for individuals with decreased kidney function, heart failure, or a history of alcohol dependence. Long-term use may also lead to vitamin B12 deficiency.

GLP-1 Receptor Agonists: Mimicking Natural Hormones

GLP-1 receptor agonists work by mimicking a natural hormone that stimulates insulin release when food is consumed. They also slow down digestion and suppress appetite, often leading to significant weight loss. Most GLP-1 agonists are administered via injection, although semaglutide (Rybelsus) is available in oral form.

Common medications in this class include:

• dulaglutide (Trulicity)
• exenatide (Byetta)
• liraglutide (Victoza)
• lixisenatide (Adlyxin)
• semaglutide (Ozempic, Rybelsus)

Potential side effects of GLP-1 receptor agonists include nausea, vomiting, and diarrhea. In rare cases, pancreatitis can occur.

Dual and Triple Agonists: The Next Generation

Emerging as powerful new options are dual and triple agonists. Dual agonists target both GLP-1 and GIP receptors, while triple agonists are currently in clinical trials and aim to target GLP-1, GIP, and glucagon receptors. These medications offer the potential for even greater blood sugar control and weight loss.

Possible side effects of tirzepatide, a dual agonist, include nausea, vomiting, diarrhea, and constipation.

SGLT2 Inhibitors: Protecting Kidneys and Hearts

Sodium-glucose cotransporter-2 (SGLT2) inhibitors prevent the kidneys from reabsorbing sugar, allowing it to be excreted in urine. These medications are particularly recommended for individuals with heart failure or chronic kidney disease.

Available SGLT2 inhibitors include:

• bexagliflozin (Brenzavvy)
• canagliflozin (Invokana)
• dapagliflozin (Farxiga)
• empagliflozin (Jardiance)
• ertugliflozin (Steglatro)

Possible side effects include increased urinary frequency, dizziness, vaginal yeast infections, urinary tract infections, and dehydration. Rarely, these medications can cause serious complications such as low blood pressure or diabetic ketoacidosis.

Other Medication Classes

Several other classes of medications are also used to manage type 2 diabetes, each with its own mechanism of action and potential side effects.

DPP-4 Inhibitors

Dipeptidyl peptidase-4 (DPP-4) inhibitors enhance insulin release by blocking the enzyme that breaks down incretin hormones. Medications in this class include alogliptin (Nesina), linagliptin (Tradjenta), saxagliptin, and sitagliptin (Januvia). Potential side effects include headaches, nausea, and joint pain. Individuals with pre-existing heart conditions may also be at increased risk for pancreatitis or heart failure.

Sulfonylureas

Sulfonylureas are older medications that stimulate the pancreas to release more insulin. While effective and relatively inexpensive, they carry a higher risk of hypoglycemia (low blood sugar) and weight gain. Medications in this class include glimepiride, glipizide, and glyburide (DiaBeta). These medications are generally not recommended for individuals with kidney or liver disease.

Meglitinides

Meglitinides also stimulate insulin release from the pancreas and act quickly. Potential side effects include hypoglycemia and weight gain. Medications in this class are repaglinide and nateglinide.

Thiazolidinediones

Thiazolidinediones (TZDs) improve insulin sensitivity, allowing the body to use insulin more effectively. They are prescribed less frequently due to potential risks like heart failure and bone fractures. Medications in this class include pioglitazone (Actos) and rosiglitazone.

D2 Agonist

Bromocriptine (Cycloset, Parlodel) is an oral medication that can help lower blood sugar levels. Side effects may include blurred vision, headache, and nausea, which often subside as the body adjusts.

Insulin Therapy

When oral medications and non-insulin injectables are insufficient to manage blood sugar levels, insulin therapy may be necessary. Insulin replaces the hormone the body isn’t producing adequately. Dr. Kathleen Dungan, an endocrinologist at the Ohio State University Wexner Medical Center, notes that “Most patients with type 2 diabetes who require insulin start with a single injection of long-acting (basal) insulin given once daily.”

The choice of medication for type 2 diabetes is a complex one, and should be made in consultation with a healthcare professional. The evolving landscape of treatment options emphasizes a personalized approach, considering not only blood sugar control but also the overall health and well-being of the individual.