A recent study finds that a drug used to treat attention deficit hyperactivity disorder may prove to speed patients' recovery from general anesthesia, reduce post-anesthesia complications and ultimately cut down on the time patients spend in the OR.

Researchers at Massachusetts General Hospital used adult rats to test the effect of methylphenidate (Ritalin) - a stimulant widely used to treat ADHD - on time to emergence from general anesthesia. They also performed experiments to test the effects of methylphenidate on sedation and respiratory depression by general anesthesia. The study was designed to see whether methylphenidate could stimulate arousal in rats receiving the anesthetic drug isoflurane, according to MGH.

The first experiments showed that animals receiving intravenous methylphenidate 5 minutes before discontinuation of isoflurane recovered significantly faster than rats receiving a saline injection. Another experiment showed that methylphenidate induced signs of arousal, such as movement and standing, in animals continuing to receive isoflurane at a dose that would have been sufficient to maintain unconsciousness. EEG readings taken during that experiment showed that brain rhythms associated with arousal returned within 30 seconds of methylphenidate administration.

"Our results tell us that, even though we don't yet know the precise mechanisms underlying general anesthesia, we can overcome its effects by activating arousal pathways," says Ken Solt, MD, of MGH's department of anesthesia, critical care and pain medicine and the study's lead author, in a statement.

Dr. Solt adds that further testing will be performed at MGH, gauging the actions of methylphenidate with other anesthetic agents to see if these effects are broadly applicable. If these findings can be replicated in humans, the study's authors note, post-anesthesia complications such as delirium and cognitive dysfunction could potentially be reduced in pediatric and elderly patients as well.

"We also found that methylphenidate increased respiration in anesthetized animals, which could help rescue patients who receive too much sedation for simple procedures," says study co-author Emery Brown, MD, PhD. "And the ability to safely reduce the time patients spend in the operating room - which can cost between $1,000 and $1,500 an hour - could translate into significant savings in health costs."

Mark McGraw