Older oral agents for type 2 diabetes, such as sulfonylureas and metformin, control blood sugar levels at least as well as newer, more expensive agents, such as the thiazolidinediones (Actos, Avandia), findings from a review study suggest.
Still, further research is needed to determine if the older and newer drugs have comparable long-term effects, according to the report in the Annals of Internal Medicine.
Dr Shari Bolen, from Johns Hopkins University in Baltimore, and colleagues searched various medical databases to identify studies examining benefits and harms of oral diabetes drugs. A total of 216 relevant studies and two systematic reviews were identified.
There were limited data available on the impact that these drugs had on major outcomes, such as death from heart disease, so the researchers limited their comparison to intermediate endpoints, such as how well the drug controls blood sugar levels.
Older drugs as good
As noted, the older drugs controlled blood sugar levels about as well as the thiazolidinediones did. There were some differences, however, in other effects.
Thiazolidinediones were the only drugs that increased HDL "good" cholesterol levels, but they also increased LDL "bad" cholesterol levels. Metformin reduced LDL cholesterol levels, while the other agents appeared to have no effect on cholesterol levels.
With the exception of metformin, the drugs generally increased body weight by 1 to 5 kilograms. Compared with other drugs, sulfonylureas and repaglinide were tied to increased risks of low blood sugar, thiazolidinediones were linked to heart failure, and metformin raised the risk of stomach and intestinal problems.
"Each oral diabetes agent is associated with adverse events that counterbalance its benefits," the researchers conclude. "Overall, metformin seemed to have the best profile of benefit to risk."
SOURCE: Annals of Internal Medicine, September 18, 2007. – (ReutersHealth)