Rats given the drug regained consciousness in about one-third of the time it took those given a placebo.
If the same effect is found in humans, the drug would be the first safe and effective way to reverse the effects of general anesthesia, the researchers said.
"This offers a new approach to waking up patients at the end of surgery," said study researcher Dr. Ken Solt, an anesthesiologist at Massachusetts General Hospital in Boston. "The current paradigm really is to just let these drugs wear off at the end of surgery," Solt said.
The drug could help rescue people who have stopped breathing because they have been given too much sedation, Solt said.
Waking people up faster after an operation might also save on health care costs. Use of an operating room can cost between $1,000 and $1,500 dollars and hour. Because about 100,000 people in the United States are put under general anesthesia every day "The incremental cost savings could be tremendous," Solt said.
However, the researchers conducted experiments with only one type of anesthesia drug, and it's not clear whether Ritalin could reverse the effects of others. In addition, the drug, generically known as methylphenidate, has side effects including an increased heart rate, and may not be suitable for certain patients.
The study is published in the October issue of the journal Anesthesiology.
Waking up rats
In one experiment, Solt and colleagues anesthetized rats by having them inhale the anesthesia drug isoflurane. After they were taken off the anesthesia, methylphenidate (administered by IV) reduced the time it took for the rats to wake up by about three minutes.
In another experiment, the rats continuously inhaled isoflurane at a dose that kept them unconscious. Then, the researches simultaneously administered methylphenidate. After giving the drug, the rats showed signs of arousal, such as moving their heads and opening their eyes, even though the isoflurane would normally have kept them unconscious.
Methylphenidate might reverse anesthesia in two ways: it could stimulate pathways in the brain that are involved in arousal, and it could increase breathing rate, which would remove isoflurane from the brain faster, Solt said.
"I think this is an excellent piece of work," said Anthony Hudetz, a professor of anesthesiology, physiology and biophysics at the Medical College of Wisconsin, who was not involved in the study. "I can imagine[methylphenidate] eventually being used," to wake people up after surgery, Hudetz said.
In addition, the study also has some basic science implications.
Despite its use for more than a century, researchers don't understand exactly how anesthesia works. One way to try to figure this out has been to study the brains of people as they receive anesthesia, Hudetz said.
But another way is to study a mechanism that reverses anesthesia-induced unconsciousness. This study helps elucidate the biochemical and neuronal pathways that are involved in anesthesia's effects, Hudetz said.
Pass it on: Ritalin may speed up recovery time in those who are put under general anesthesia for surgery.