EB: OTC Painkillers Also Help Grandpa Get Buff

By Todd Neale
SAN DIEGO, April 8 -- Over-the-counter painkillers may promote muscle growth in older patients during weight training, a randomized, placebo-controlled study showed.
In 24 patients with a mean age of 64, recommended daily doses of ibuprofen and acetaminophen were associated with gains of about 50% in muscle volume and strength compared with placebo after 12 weeks of resistance training, Chad Carroll, Ph.D., of Ball State University in Muncie, Ind., and colleagues reported at the Experimental Biology meeting here.
"These results suggest that chronic consumption of ibuprofen or acetaminophen during resistance training induces intramuscular changes that enhance the metabolic response to resistance exercise," said Todd Trappe, Ph.D., also of Ball State.
He said that the results were unexpected, because in an earlier study of younger patients (mean age 25) they found that the two drugs interfered with muscle building after a single bout of exercise.
"We weren't even considering the fact that this was going to cause muscle growth," he said of the current study.
The researchers decided to examine the effects of the two analgesics in a double-blind, placebo-controlled study in older patients because they are most likely to take them chronically for conditions such as osteoarthritis.
They randomized 36 participants to placebo (eight males, four females; mean age 67), 1,200 mg of ibuprofen a day (nine males, four females; mean age 64), or 4,000 mg of acetaminophen a day (seven males, four females; mean age 64). The daily drug doses were divided into three times a day. Participants in all three groups performed knee-extensor resistance training three times a week for 12 weeks.
Compared with placebo, participants taking ibuprofen had greater gains in quadriceps volume (11 ± 2% versus 9 ± 1%) and strength (30 ± 3% versus 23 ± 2%), but the results did not reach statistical significance (P=0.06 for both).
When males were considered alone, there were significantly greater increases in volume (11 ± 2% versus 8 ± 2%) and strength (29 ± 4% versus 20 ± 3%) (P<0.05 for both).
Also compared with placebo, participants taking acetaminophen had nonsignificantly greater gains in quadriceps volume (13 ± 1% versus 9 ± 1%) and strength (28 ± 3% versus 23 ± 2%) (P=0.06 for both).
Again, when males were considered alone, there were significantly greater increases in volume (13 ± 1% versus 8 ± 2%) and strength (26 ± 3% versus 20 ± 3%) (P<0.05 for both).
Blood screening indicated that liver and kidney function were normal in all participants.
Dr. Trappe said that the mechanism behind these gains was unclear, but speculated that it might involve the inhibition of the isoforms of cyclooxygenase by these two drugs.
The body may have adapted to the chronic use of the analgesics by producing more cyclooxygenase to compensate, which would set the muscles up for a more robust response to the exercise and, consequently, more muscle mass, the researchers said.
"I don't know if that's what happened," he said, "but that's what we're looking into."
A literature review is ongoing to compare the gains associated with ibuprofen and acetaminophen with those from other supplements such as growth hormone and testosterone.
"But I don't think you're going to find anything out there that's going to give a more robust response in this population," he said, "and I'm not sure you're going to find anything that might even equal it."
He added that it would be premature to make any recommendations on taking these two analgesics considering the potential side effects associated with chronic use.
Ibuprofen has been associated with gastrointestinal bleeding and kidney problems, he said, and acetaminophen might cause liver damage.
Nevertheless, he said, this study "is really going to open up some doors into understanding the mechanisms that control muscle growth in ways that we can manipulate in older people."
The study was funded by the National Institute on Aging.
The authors reported no conflicts of interest.
Primary source: Experimental Biology MeetingSource reference:Carroll C, et al "Ibuprofen and acetaminophen promote muscle hypertrophy and strength gains during resistance exercise in the elderly" EB Meeting 2008; Abstract 753.31.