This article is more than 5 years old. Information may no longer be current.
Older diabetes drugs produced similar glycemic effects as new drugs
Metformin led the pack with similar blood glucose control as newer drugs but decreased LDL and weight maintenance.
Click Here to Manage Email Alerts
Researchers have compared different diabetes drugs and found that although each drug demonstrated favorable glycemic control, the frontrunner was metformin.
Metformin was found to control blood glucose levels similarly to other oral diabetes agents, yet maintained weight and decreased LDL cholesterol, according to the study published in Annals of Internal Medicine.
Physicians “should feel comfortable prescribing the older medications over the newer ones,” Shari Bolen, MD, MPH, instructor, division of general internal medicine, Johns Hopkins University, told Endocrine Today. “Newer medications, such as thiazolidinediones and meglitinides, are just as effective as older diabetes medications and no safer than older medications. In this case, the older, cheaper drugs are just as effective as the newer, more expensive medications.”
Bolen and colleagues conducted a comprehensive systematic review of different oral diabetes agents, including TZDs, metformin, second-generation sulfonylureas, meglitinides and alpha-glucosidase inhibitors.
New vs. old
A search of the MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials databases turned up 216 controlled trials and two systematic reviews that assessed the risk–benefit profile of oral diabetes drug classes available in the United States.
Sulfonylureas, TZDs, metformin and repaglinide (Prandin, Novo Nordisk) generally improved glycemic control to the same degree — each reduced HbA1c by about one absolute percentage point. Nateglinide (Starlix, Novartis) and alpha-glucosidase inhibitors like acarbose (Precose, Bayer) and miglitol (Glyset, Pfizer) had slightly less powerful effects on HbA1c.
Glimepiride (Amaryl, Sanofi Aventis), glipizide (Glucotrol, Pfizer) and glyburide produced the most frequent rates of hypoglycemia compared with other oral agents. There were fewer reported rates of hypoglycemia among patients who took metformin or TZDs, such as pioglitazone (Actos, Takeda) and rosiglitazone (Avandia, GlaxoSmithKline).
Bolen and colleagues also investigated the effects on lipid profile. TZDs were the only drug class that had a slightly beneficial effect on HDL cholesterol (3 mg/dL to 5 mg/dL); however, this class also had a harmful effect on LDL cholesterol (10 mg/dL) compared with other oral agents. Metformin improved LDL cholesterol by about 10 mg/dL. Sulfonylureas and alpha-glucosidase inhibitors did not have any effect on LDL cholesterol.
Metformin and acarabose were weight neutral compared with all the other drugs, which increased body weight by 2 lb to 11 lb.
Further adverse issues
“Each oral diabetes agent is associated with adverse events that counterbalance its benefits,” the researchers wrote. “Overall, metformin seemed to have the best profile of benefit to risk.”
The most commonly reported adverse events with metformin were digestive problems and diarrhea. Metformin has been previously associated with lactic acidosis, especially in patients with chronic kidney disease and chronic heart failure. However, lactic acidosis was just as common in patients taking metformin as other oral antidiabetic agents. Other adverse events included high risk for hypoglycemia with sulfonylureas and repaglinide and increased risk for heart failure with TZDs.
The researchers also noted cost differences; metformin and sulfonylureas may save patients more money in the long-run compared with newer drugs such as TZDs ($100 vs. $400 per year).
“Compared with newer agents, metformin and second-generation sulfonylureas share three additional advantages: lower cost, longer use in practice and more intense scrutiny in long-term trials with clinically relevant endpoints,” they wrote.
“Sometimes newer medications turn out to be better in the long-run. For instance, metformin was a new medication in 1995 and is an excellent agent compared with second-generation sulfonylureas, which preceded it,” Bolen said. “Also, we generally have less data on newer medications, so they may be a bit more risky to use over older medications until they have been on the market for a while.” – by Katie Kalvaitis
For more information:
- Bolen S, Feldman L, Vassy J, et al. Systematic review: comparative effectiveness and safety of oral medications for type 2 diabetes mellitus. Ann Int Med [online]. 2007;147