Ritalin (methylphenidate), the stimulant drug commonly used to treat attention deficit/hyperactivity disorder, may speed recovery from anesthesia, according to new research in rats that found that animals awakened from anesthesia three times faster when given the medication rather than a placebo and also recovered regular breathing more quickly.
Although there are drugs that can reverse the effects of some surgical medications — for example, the drug naloxone is a widely-used antidote to potent opioids used in the operating room — there have been no medications to date that could be used to “turn off” the effects of the most common anesthetics, like propofol and anesthetic gases.
“This is a major new result because it shows that we can wake the brain up from general anesthesia,” says Dr. Emery Brown, professor of computational neuroscience at MIT and a co-author of the study.
Researchers studied a total of 26 rats in several experiments. To determine full recovery after anesthesia, the researchers measured how long it took rats that were placed on their backs while unconscious to right themselves and stand on all four paws after the anesthetic was stopped. The animals were injected with either the placebo or Ritalin five minutes before inhaled anesthesia was stopped. Rats that got placebo took 280 seconds to get back up; rats given Ritalin took just 91 seconds.
In one experiment using the highest dose of Ritalin, the authors gave the drug to rats that had been under for 40 minutes and found that they began to right themselves within 30 seconds, even while the anesthetic was still being inhaled. The animals stayed active while both medications were continued.
Speeding recovery from anesthesia may improve outcomes in many surgical patients. Many find waking up to be distressing and up to 20% of patients (and up to 30% of children) become delirious. Elderly patients are also more prone to delirium and to postoperative cognitive problems, which can sometimes become chronic. “An anesthetic shouldn’t last any longer than needed,” Brown says. “Once [the operation is] done, we should try have people come back as quickly as possible.”
A quick return to consciousness could also have important financial implications for hospitals and the health care system. Anything that reduces a patient’s time in a heavily monitored operating or recovery room — even by just a few minutes per patient — could add up to substantial savings, when you consider the 100,000 people who undergo operations requiring anesthesia daily. An operating room costs at least $1,000 an hour to run.
Brown thinks giving Ritalin may cause wakefulness — and help reduce surgical patients’ postoperative cognitive dysfunction — for the same reasons it improves thinking in people with ADHD. “If you look at the brains of children with ADHD and have them do tasks [that require attention], you’ll find that their prefrontal cortex (PFC) is less active than it is in the brains of those who are typically developing and executing the same task,” he explains.
Ritalin increases the availability of the neurotransmitter dopamine in the PFC and allows this region to become more active. That may be an important part of consciousness, and Ritalin may restore control to this part of the brain more rapidly. The PFC is involved in planning, decision-making and the ability to consciously guide behavior.
The medication may also reduce patients’ delirium by shortening the time that they’re unconscious. Delirium is associated with longer surgeries and with longer time spent without breathing naturally.
Despite the new findings in rats, a small number of previous studies in humans did not help people awaken faster. In these cases, however, the drug was administered after people had already been taken to the recovery room, so Brown thinks it might not have been given quickly enough. But these studies did show improved breathing with Ritalin.
“The next step is try this in humans,” says Brown, noting that since Ritalin has a long history of safe use, adding it into anesthesia practice would be easier than using a brand new drug — if it is shown to work, that is. “It all needs to be proved. But right now there’s nothing we can do [to reverse anesthesia] and that’s not the right answer.”
The research was published in the journal Anesthesiology.