Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Delayed-release stimulant used to treat ADHD may be less subject to abuse

02.03.2006


A team led by Massachusetts General Hospital (MGH) researchers has found that a delayed-release stimulant used to treat attention-deficit hyperactivity disorder (ADHD) may be less likely to be abused than other stimulant drugs. Study participants taking therapeutic oral doses of Concerta, a once-daily form of the drug methylphenidate, did not report perceiving and enjoying the drug’s subjective effects, features that are associated with a medication’s potential for abuse. The report appears in the March 2006 issue of The American Journal of Psychiatry.



"We know that drugs that cause euphoria are potentially abusable, and euphoria requires rapid delivery to the brain. Using sophisticated PET scan imaging, we were able to examine the rate of delivery of both rapid- and delayed-release formulations of methylphenidate and correlate those results with how the drugs felt to study volunteers," says Thomas Spencer, MD, of the MGH Pediatric Psychopharmacology Unit, the paper’s lead author. "The ability to show that rate of brain delivery may determine abuse potential is important to our understanding of the safety of different formulations."

Methylphenidate and other stimulant drugs used to treat ADHD act by blocking the dopamine transporter, a molecule on brain cells that takes up the neurotransmitter dopamine, raising its level in the brain. Studies have shown that the brains of ADHD patients have abnormal regulation of dopamine, which plays a key role in the control of movement, behavior and attention. While stimulants are effective for controlling ADHD symptoms, the drugs are also subject to abuse, so the current study was designed to compare the abuse potential of two formulations of methylphenidate.


The researchers compared a traditional, quick-release form of the drug with Concerta, a formulation that is released over 12 hours to produce a gradual increase in blood levels. With Concerta, the drug passes slowly through a hole in capsules that do not dissolve, reducing the possibility that the gradual-release feature might be bypassed. Study participants received the two medications at dosages designed to produce comparable peak levels in the blood and brain.

Twelve adult volunteers, none diagnosed with ADHD or any neurological or psychiatric disorder, were randomly assigned to receive either the immediate-release or delayed-release form of methylphenidate on two separate days. PET scans – which showed whether or not the dopamine transporter molecule was occupied by the medication – were taken the day before drug administration as a baseline, one and three hours after the first drug administration and five and seven hours after a second drug administration on a different day. During the 10 hours after each drug administration, hourly blood samples were taken from the volunteers, who also completed hourly questionnaires regarding whether they were aware of the drug’s effects and whether they enjoyed or disliked those effects.

As expected, the delayed-release formulation took longer to produce maximum blood levels and blockade of the dopamine transporter than did the immediate-release drug. While most of those receiving immediate-release methylphenidate reported detecting and enjoying the drug’s activity, few of those receiving the delayed-release form were aware of or enjoyed the drug’s effects.

"The differing reports on feeling and liking the drug effects occurred despite using larger doses of the delayed-release formulation and the equivalent peak blood and brain levels," says Spencer. "Previous studies have showed that both versions are effective for treating ADHD. Whether delayed- or sustained-release formulations of other potentially abusable ADHD drugs share the same safety characteristics needs be studied, since different forms vary in the levels and timing of drug delivery." Spencer is an associate professor of Psychiatry at Harvard Medical School.

Sue McGreevey | EurekAlert!
Further information:
http://www.mgh.harvard.edu/

More articles from Health and Medicine:

nachricht Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University

nachricht Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>