Oral Drug Treatment of Type 2 Diabetes Mellitus: A Clinical Practice Guideline From the American College of Physicians FREE

The American College of Physicians (ACP) developed these recommendations. Members of the ACP are internists, specialists in the care of adults.

Type 2 diabetes mellitus interferes with the body's ability to store energy from food, resulting in high levels of blood sugar that can lead to such problems as kidney failure, blindness, and heart disease. Insulin helps the body convert food to stored energy and keeps blood sugar levels within the normal range. In type 2 diabetes, body tissues are resistant to the effects of insulin and blood sugar levels are high. Some patients can overcome these abnormalities with diet and exercise alone. However, many patients need to add drug treatment to control blood sugar levels. Drugs include insulin, an injectable drug, and a variety of oral drugs. Usually, oral drugs are the first line of treatment. The ACP developed these guidelines to help doctors and patients choose from among the wide variety of oral drug options available to treat type 2 diabetes.

The authors based these guidelines on a review of published English-language studies about the effectiveness of different classes of oral diabetes drugs approved by the U.S. Food and Drug Administration: metformin, sulfonylureas, meglitinides, thiazolidinediones, inhibitors of dipeptidyl peptase-1, and glucagon-like peptide-1 receptor antagonists. Each drug class can include several drugs. The guideline panel developed recommendations based on the strength of the evidence they found about the benefits and harms of various drugs.

Published studies show that metformin is more effective than other type 2 diabetes drugs in reducing blood sugar levels when used alone and in combination with other drugs. In addition, metformin reduces body weight and improves cholesterol profiles. The risk for dangerously low blood sugar levels was higher with sulfonylureas than with other drugs. Metformin was associated with fewer side effects than sulfonylureas. Most 2-drug combinations similarly controlled blood sugar levels, but some increased the risk for side effects.

Weight control with diet and exercise are key parts of diabetes treatment.

Doctors should prescribe an oral drug for patients diagnosed with type 2 diabetes when diet, exercise, and weight loss fail to adequately control blood sugar levels.

When a drug is added to diet and exercise, the first choice should be metformin.

Doctors should add a second drug to metformin to treat patients with poorly controlled blood sugar levels. However, no strong evidence supports that one class of drug is better than another as a second drug.

Some patients with kidney problems should not receive metformin. Recommendations may change as new studies become available. The authors did not examine evidence published in languages other than English.