Medications

• Weight gain (some sulfonylureas, such as glimepiride, may produce less weight gain than others)
• Water retention
• Although sulfonylureas pose a lower risk for hypoglycemia than insulin does, the hypoglycemia produced by sulfonylureas may be prolonged and dangerous. The newer sulfonylureas, such as glimipiride, have much less risk of hypoglycemia than older sulfonylureas.
• Some sulfonylureas may pose a slight risk for cardiac events.

Sulfonylureas interact with many other drugs, and patients should be sure to inform their doctor of any medications they are taking, including alternative or over-the-counter drugs.

Meglitinides

Meglitinides stimulate beta cells to produce insulin. They include repaglinide (Prandin), nateglinide (Starlix), and mitiglinide. These drugs are rapidly metabolized and short-acting. If taken before every meal, they actually mimic the normal effects of insulin after eating. Patients, then, can vary their meal times with this drug. (Nateglinide appears to work more quickly and is shorter-acting than repaglinide). These drugs may be particularly helpful in combination with metformin or other drugs. They may also be a good choice for people with potential kidney problems.

Side Effects. Side effects include diarrhea and headache. As with the sulfonylureas, repaglinide poses a slightly increased risk for cardiac events. (Newer drugs, such as nateglinide, may pose less of a risk.) People with heart failure or liver disease should use them with caution and be monitored.

Thiazolidinedione

Thiazolidinediones include rosiglitazone (Avandia) and pioglitazone (Actos). They improve insulin sensitivity by activating certain genes involved in fat synthesis and carbohydrate metabolism. These drugs are usually taken once or twice per day; however, it may take several days before the patient notices any results from them and several weeks before they take full effect. Thiazolidinediones are usually taken in combination with other oral drugs or insulin.

In some studies, thiazolidinediones have produced favorable effects on the heart, including reducing blood pressure and preventing blood clots. A 2006 study found that pioglitazone reduced the risk of heart attack, stroke, and acute coronary syndrome. Research presented at the 2005 American Heart Association meeting indicated that pioglitazone may be especially helpful in preventing a second heart attack for patients with type 2 diabetes who have suffered a previous heart attack. Evidence suggests that pioglitazone is superior to rosiglitazone in improving triglyceride and HDL levels. In addition, some evidence suggests that these drugs may preserve beta-cell function and, if used early, may help prevent progression of diabetes. This effect has not been observed with other oral drugs.