The drugs for type 2 diabetes attempt to get rid of extra sugar in the blood or to help the body to better utilize insulin. Most of them are taken orally. Occasionally they are injectable, or sometimes a type 2 diabetic will be given insulin to inject. Some of the drugs given for type 2 diabetes include:
- Alpha-glucosidase inhibitors: Interfere with the absorption of starch and sugar in the small intestine. They are generally taken before meals and include, acarbose (Precose), miglitol (Glyset), and voglibose. They are contraindicated in patients with kidney disease, liver disease, diabetic ketoacidosis, inflammatory bowel disease, ulcerative colitis, intestinal obstruction, any chronic intestinal disease disrupting digestion/absorption, any condition that may deteriorate because of increased gas formation in the intestine. GI side effects are common. They include flatulence, diarrhea, nausea, and abdominal pain. They can also cause hypoglycemia which is treatable with glucose tablets (not table sugar, which is blocked by the drug). Acarbose can cause an increase in liver enzymes.
- Biguanides (metformin, Glucophage): Decrease the amount of sugar produced by the liver by preventing it from converting fats and amino-acids into glucose. They also activate an enzyme (AMPK) which helps cells to respond more effectively to insulin and take in glucose from the blood. Metformin decreases vitamin B12 levels and supplementation should be considered for those taking the drug. Metformin is commonly combined with other diabetes drugs. Common side effects include: include: lactic acidosis, diarrhea, nausea, vomiting, and flatulence. Lactic acidosis is a medical emergency. Symptoms of lactic acidosis include extreme fatigue, weakness, decreased appetite, nausea, vomiting, dizziness, trouble breathing, lightheadedness, feeling cold, tachycardia, or bradycardia. People with kidney problems are more prone to lactic acidosis. Metformin is contraindicated in patients with heart failure, recent heart attack, or liver problems.
- Dopamine agonist: Bromocriptine is a sympatholytic D2-dopamine agonist that has been approved for the treatment of type 2 diabetes. It is thought to act on the hypothalamus (circadian neuronal activities), to reset an abnormally elevated hypothalamic drive for increased plasma glucose, free fatty acids, and triglycerides in insulin-resistant patients. It is believed that giving the drug within two hours of awakening is believed to augment low hypothalamic dopamine levels and inhibit excessive sympathetic tone within the central nervous system. This causes a reduction of plasma glucose levels after eating by enhancing the suppression of glucose production in the liver. Common side effects include nausea and dizziness (especially when getting up from a lying or sitting position). Side effects that appear less commonly include confusion, hallucinations, and uncontrolled movements of the body, although these are reported more often in patients with Parkinson’s disease. Very rarely the patient may have stomach pain, increased urination, low back pain, runny nose, weakness, loss of appetite, weakness, convulsions, tachycardia, vision changes, nausea/vomiting, and chest pain.
- Glucagon-like peptide -1 receptor agonists: These drugs mimic hormones that help lower blood sugar levels after a meal. They suppress glucagon secretion, delay gastric emptying, and increase satiety. These include exenatide (Byetta/Bydureon), liraglutide (Victoza, Saxenda), lixisenatide (Lyxumia), albiglutide (Tanzeum), dulaglutide (Trulicity), and semaglutide (Ozempic). It is controversial, but these drugs may increase the risk of pancreatitis, pancreatic cancer, and thyroid cancer. The most common adverse effect is nausea or vomiting.
- Meglitinides: These drugs help the insulin-producing beta cells in the pancreas to release insulin. These include repaglinide (Prandin) and nateglinide (Starlix). Because these drugs are fast-acting, they must be taken right before each meal. Meglitinides are not approved for use in pregnant or breastfeeding women, or in children. Side effects include hypoglycemia, weight gain, GI upset, and back pain.
- Sodium glucose transporter (SGLT) 2 inhibitors: These drugs work by preventing the kidneys to hold on to glucose. They include dapagliflozin (Farxiga), dapagliflozin-metformin (Xigduo XR), canagliflozin (Invokana), canagliflozin-metformin (Invokamet), empagliflozin (Jardiance). The U.S. Food and Drug Administration released warnings about the side effects of these drugs that can be fatal. These include acute kidney injury, urinary tract infection
- Sulfonylureas: These are among the oldest diabetes drugs still used today. They work by stimulating the pancreas with the help of beta cells. This causes your body to make more insulin. These include glyburide (DiaBeta, Glynase), glimepiride (Amaryl), chlorpropamide (Diabinase), glipizide (Glucotrol), and tolazamide (Tolinase). Side effects include hypoglycemia, hunger, weight gain, skin reactions, GI upset, and dark-colored urine. Should not be taken by people with kidney problems. They also can make the patient sensitive to sunlight.