U.S. study throws light on effects of Ritalin drug

02:51 PM ET 09/28/98

WASHINGTON (Reuters) - Researchers said Monday they had explained why the drug Ritalin, given to hyperactive youngsters,does not become addictive when taken orally. They said it takes an hour for the stimulant, known generically as methylphenidate, to reach its peak concentration in the brain -- compared with five minutes for cocaine. ``The fact that Ritalin taken orally is drawn so slowly into the brain is a likely reason why patients do not experience a 'high' from this means of use,'' the National Institute on Drug Abuse (NIDA), which funded the study, said in a statement. The use of Ritalin to treat attention deficit disorder (ADD) and attention deficit hyperactivity disorder (ADHD) is controversial, with some critics arguing that it is wrong to drug children. But several studies have supported the use of the drug. The American Medical Association says it has found little evidence that Ritalin, made by Novartis and also available generically, is over-used. The AMA found that an estimated 3 to 6 percent of the school-age population may have ADD or ADHD. Children diagnosed with the conditions exhibit a series of problems including inattentiveness, poor listening skills, failure to follow instructions and difficulty organizing tasks. Market research firm IMS Health says 13.9 million prescriptions of stimulants including Ritalin were dispensed to children during the last school year, an 81.2 percent increase from the 7.7 million recorded five years earlier. Dr. Nora Volkow and colleagues at Brookhaven National Laboratory in New York used brain scans to measure the drug's effects in the brain. The positron emission tomography (PET) scans on seven adult volunteers who do not have ADHD showed the drug did what it is supposed to do -- block chemicals known as dopamine transporters, which in turn cuts down on the amount of dopamine used in the brain. Dopamine is a neurotransmitter, or message-carrying chemical, linked with feelings of euphoria. It is believed to beat the heart of drug addiction. Of the seven volunteers, only one reported Ritalin produced a ``high''. In contrast, Ritalin given intravenously does produce a ``high'' and can be addictive.

Want to contact me?  Press here: JamesL_Jackson@msn.com
Return to the PDD Support Home Page