Formoterol, a medication used to treat asthma and other lung diseases, improves fat burning and protein metabolism in men, a new study finds. The results will be presented Saturday at The Endocrine Society's 93rd Annual Meeting in Boston.
"Research in animals has shown that formoterol can stimulate the growth of muscle and the burning of fat. This is the first study demonstrating the beneficial metabolic effects of formoterol in humans," said the study's lead author Paul Lee, MD, PhD, a research fellow at the Garvan Institute of Medical Research in Sydney.
The discovery is important, Lee said, because "it suggests that formoterol may be used in the future to prevent obesity and muscle loss in humans."
With funding from the National Health Medical Research Council Australia, Lee and colleagues studied the drug in eight healthy men over one week. All men had a healthy weight and received a low daily dose of formoterol in a pill, Lee said. To find the optimal dose, the authors studied three doses in four of the men: 80, 160 or 320 micrograms per day. He said they found that the 160-microgram dose had metabolic benefits without raising heart rate.
All eight men underwent metabolic testing before and after treatment with 160 micrograms daily of formoterol. One week of formoterol treatment increased metabolism in the men by more than 10 percent, according to an estimate of the resting energy expenditure (the calories needed at rest during 24 hours). The rate of fat oxidation, or burning, rose by almost 25 percent, indicating there may be a loss of fat in the long term, Lee reported.
Additionally, the researchers determined the rate of protein burning before and after treatment.
"Protein is the building block for muscle in the body," Lee explained. "Burning less protein means preservation of muscle and may increase muscle mass in the long term."
After formoterol treatment the protein burning rate fell close to 15 percent, he said. They used the leucine turnover technique, which tracks the synthesis and breakdown of the amino acid leucine. According to Lee, it is the most accurate method of estimating protein metabolism in humans.
Lee said none of the volunteers reported any major side effects from the 160-microgram dose. Tachycardia, or fast heart rate, is a known side effect of older medications in the same drug class as formoterol, especially at high doses. Low dose formoterol, similar to the one used in this clinical study, resulted in no substantial adverse cardiac effects in animal studies, he said.
"Our results call for further research to investigate whether formoterol improves body composition, physical health and function," Lee said.