Thiazolidinediones: Oral Medication for Type 2 Diabetes

diabetes pills
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Thiazolidinediones are oral medications that help lower blood sugar in type 2 diabetes. In addition to a healthy diet and exercise, they are another way to control blood sugar levels. They are also known as glitazones.

In the U.S., thiazolidinediones currently available include Actos (pioglitazone), Avandia (rosiglitazone), and the combination drug Avandamet (rosiglitazone and metformin). The FDA lifted prescription restrictions on rosiglitizone in 2013 after concluding new evidence showed no increased risk of heart attack, but bans remain in place in Europe.

Dos and Dont's

Thiazolidinediones help to lower insulin resistance in cells, improving the way that the body responds to insulin. They are typically taken by mouth once or twice daily. Additionally, they may be used alone, with other pills, or with insulin. Thiazolidinediones neither replace insulin in the body nor do they prompt the body to create additional insulin. They are not meant to replace the healthy diet a doctor recommends either.

History of Use

Since the late 1990s, thiazolidinediones have been used to treat type 2 diabetes. The first drug in this class, Rezulin, was removed from the U.S. market because of rare but serious liver problems. Some reports have raised concerns about an increased risk of heart failure in patients taking Avandia. Other reports have suggested an increased risk of heart attack with thiazolidinediones, although this link remains unproven.

The FDA ordered, in 2006, that drug labels for Avandia warn of increased risk of heart attacks and chest pain in some patients. Use of Avandia dropped significantly after the first warnings were issued. In 2010 the FDA restricted new prescriptions for Avandia to only people who were not able to control their blood glucose with other diabetes medications or who were unable to take Actos. 

In 2013, the results of the RECORD clinical trial found no increased risk of heart attack with Avandia (rosiglitazone). As a result, in 2013 the FDA lifted the prescribing restrictions it placed on Avandia. On December 16, 2015, the FDA eliminated the Risk Evaluation and Mitigation Strategy for rosiglitazone-containing medications, concluding that the benefits outweigh the risks.

However, the European Medicines Agency suspended sales of rosiglitazone in 2010 and the French and German Medicines Agencies also suspended use of pioglitazone (Actos) in 2011.

Side Effects and Risks

Common side effects include weight gain, upper respiratory infections, sinus infections, headaches, and mild anemia. Serious side effects include fluid retention, heart failure, weight gain, and muscle pain. Other side effects may include headaches, high cholesterol, weakened bones, eye problems and hives.

While there is no current evidence indicating that Actos or Avandia cause liver problems, it’s wise to keep an eye out for such symptoms as nausea, vomiting, abdominal pain, fatigue, loss of appetite, jaundice (yellowing of the skin and eyes), and dark urine.

Who Should Not Use Thiazolidinediones

People with type 1 diabetes (requiring regular insulin injections), heart failure, or liver disease should not use thiazolidinediones. Children and pregnant or nursing women should also avoid using these medications. People with eye or bone problems should talk with their health care providers before taking thiazolidinediones.

Other “Off-Label” Uses

Actos may help in treating high cholesterol. Thiazolidinediones may also help to increase ovulation and fertility in polycystic ovary syndrome.

What Else to Know About Thiazolidinediones

Thiazolidinediones should be taken every day. They may take up to three months to take full effect. If one experiences any side effects, particularly swelling, sudden weight gain, difficulty breathing, heart palpitations, menstrual changes, or broken bones, notify a healthcare provider immediately.

People with diabetes, however, should not stop taking their medication unless instructed to do so. It is important to see a doctor for close follow-up care while taking thiazolidinediones. This should include blood sugar testing, liver function tests, and eye testing.

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