7 replies to this topic

[modaritalin]

Question: whether long-term use of Ritalin damaged your neural pathway?

I was doing related search in the university library for a whole day, but cannot find definite answer on this from academic research. Most of the articles either use animals or focus on short-term effects.

Many thanks.

[FunkOdyssey]

Don't think you're going to find anything talking about methylphenidate damaging anything. On the contrary:

Curr Neuropharmacol. 2008 Dec;6(4):379-85.
Neuropharmacological mechanisms underlying the neuroprotective effects of methylphenidate.

Volz TJ.

Department of Pharmacology and Toxicology, University of Utah, 30 South 2000 East, Room 201, Salt Lake City, UT 84112, USA.
Abstract

Methylphenidate is a psychostimulant that inhibits the neuronal dopamine transporter. In addition, methylphenidate has the intriguing ability to provide neuroprotection from the neurotoxic effects of methamphetamine and perhaps also Parkinson's disease; both of which may likely involve the abnormal accumulation of cytoplasmic dopamine inside dopaminergic neurons and the resulting formation of dopamine-associated reactive oxygen species. As delineated in this review, the neuroprotective effects of methylphenidate are due, at least in part, to its ability to attenuate or prevent this abnormal cytoplasmic dopamine accumulation through several possible neuropharmacological mechanisms. These may include 1) direct interactions between methylphenidate and the neuronal dopamine transporter which may attenuate or prevent the entry of methamphetamine into dopaminergic neurons and may also decrease the synthesis of cytoplasmic dopamine through a D2 receptor-mediated signal cascade process, and 2) indirect effects upon the functioning of the vesicular monoamine transporter-2 which may increase vesicular dopamine sequestration through both vesicle trafficking and the kinetic upregulation of the vesicular monoamine transporter-2 protein. Understanding these neuropharmacological mechanisms of methylphenidate neuroprotection may provide important insights into the physiologic regulation of dopaminergic systems as well as the pathophysiology of a variety of disorders involving abnormal dopamine disposition ranging from substance abuse to neurodegenerative diseases such as Parkinson's disease.

PMID: 1958785

J Neural Transm. 2006 Dec;113(12):1927-34. Epub 2006 Jun 1.
Methylphenidate exerts no neurotoxic, but neuroprotective effects in vitro.

Ludolph AG, Schaz U, Storch A, Liebau S, Fegert JM, Boeckers TM.

Department of Child and Adolescent Psychiatry, University of Ulm, Ulm, Germany. andrea.ludolph@uni-ulm.de
Abstract

Methylphenidate (MPH) is the most common used drug in child and adolescent psychiatry. Despite of this fact, however, little is known about its exact pharmacological mechanisms. Here we investigated the toxic effects of MPH in vitro in human embryonic kidney (HEK-293) cells stably expressing the human dopamine transporter (HEK-hDAT cells) and in cultured rat embryonic (E14.5) mesencephalic cultures. MPH alone (up to 1 mM) affected neither the growth of HEK-hDAT cells nor the survival of dopaminergic (DA) neurons in primary cultures after treatment up to 72 h. No differences in neuronal arborisation or in the density of synapses were detected. 1-methyl-4-phenylpyridinium (MPP(+)) showed no toxic effect in HEK-293 cells, but had significant toxic effects in HEK-hDAT cells and DA neurons. MPH (1 microM - 1 mM) dose-dependently reduced this cytotoxicity in HEK-hDAT cells and primary mesencephalic DA neurons. The presented results show that application of MPH alone does not have any toxic effect on DA cells in vitro. The neurotoxic effects of MPP(+) could be significantly reduced by co-application of MPH, an effect that is most likely explained by MPH blocking the DAT.

PMID: 16736241

If you want to get worked up about the dangers of psychostimulants you should look into amphetamines.

Edited by FunkOdyssey, 07 June 2010 - 03:00 PM.

[chrono]

Also, neurotoxicity may not be subjectively evident, especially if occurring very gradually (and hence along with other subjective alterations). Unless it's pretty severe.

[VoidPointer]

If you are determined to find negative accounts of MPH, talk to the Scientologists. They have been waging a war against MPH for decades, and even sponsored a study that was engineered to back up their theories(on monkeys evidently). They would rather have you spend thousands on their treatments than 1/100th that amount on medication.

The bottom line is that MPH is the 2nd most prescribed psychiatric medication, and has been tested extensively for 60 years in many countries. Like all medications some people can have a bad reaction, and those with heart conditions should not take stimulants. DexMPH is more effective for inattentive ADD, while MPH is better for impulsive ADHD.


I have been around kids who are on massive amounts of MPH, and believe me, they are much better off medicated than not. So far they have not yet found any major long-term effects, but who knows. It is the risk/reward ratio that is relevant here, not hyperbole.

[modaritalin]

My doc prescribe me Methylphenidate. Is this MPH or DexMPH? Thanks.

If you are determined to find negative accounts of MPH, talk to the Scientologists. They have been waging a war against MPH for decades, and even sponsored a study that was engineered to back up their theories(on monkeys evidently). They would rather have you spend thousands on their treatments than 1/100th that amount on medication.

The bottom line is that MPH is the 2nd most prescribed psychiatric medication, and has been tested extensively for 60 years in many countries. Like all medications some people can have a bad reaction, and those with heart conditions should not take stimulants. DexMPH is more effective for inattentive ADD, while MPH is better for impulsive ADHD.


I have been around kids who are on massive amounts of MPH, and believe me, they are much better off medicated than not. So far they have not yet found any major long-term effects, but who knows. It is the risk/reward ratio that is relevant here, not hyperbole.

[kassem23]

My doc prescribe me Methylphenidate. Is this MPH or DexMPH? Thanks.

If you are determined to find negative accounts of MPH, talk to the Scientologists. They have been waging a war against MPH for decades, and even sponsored a study that was engineered to back up their theories(on monkeys evidently). They would rather have you spend thousands on their treatments than 1/100th that amount on medication.

The bottom line is that MPH is the 2nd most prescribed psychiatric medication, and has been tested extensively for 60 years in many countries. Like all medications some people can have a bad reaction, and those with heart conditions should not take stimulants. DexMPH is more effective for inattentive ADD, while MPH is better for impulsive ADHD.


I have been around kids who are on massive amounts of MPH, and believe me, they are much better off medicated than not. So far they have not yet found any major long-term effects, but who knows. It is the risk/reward ratio that is relevant here, not hyperbole.

That's MPH. DexMPH is the active ingredient in Focalin, which might give better success for ADHD-PI individuals. Good luck.

[FunkOdyssey]

Can you guys cite any studies that suggest dexmethylphenidate might be superior to methylphenidate for inattentive ADHD? I think that is probably true but I'm wondering if it is actually documented anywhere.

[VoidPointer]

Can you guys cite any studies that suggest dexmethylphenidate might be superior to methylphenidate for inattentive ADHD? I think that is probably true but I'm wondering if it is actually documented anywhere.

I copied this post from the ADD forums(d-methylphenidate is DexMPH);

Differential pharmacokinetics and pharmacodynamics of methylphenidate enantiomers: does chirality matter?


Abstract

d,l-threo-methylphenidate (MPH) Ritalin is an effective first-line treatment for the symptoms associated with attention-deficit/hyperactivity disorder. threo-methylphenidate inhibits the dopamine transporter and the norepinephrine transporter, resulting in elevations of these monoamines after impulse release.


Although MPH has long been administered as a racemic mixture of the 2 enantiomers, d-MPH and l-MPH, converging lines of evidence drawn from investigations using in vitro systems, animal models, and humans indicate that it is predominantly, if not exclusively, d-MPH that mediates the pharmacological/therapeutic actions of MPH.

In both rodent and primate animal models, the binding of radiolabeled d-MPH to dopamine transporter was found to be selective, saturable, and reversible, whereas binding of l-MPH was diffuse and nonspecific. The behavioral effects of the enantiomers of MPH have been tested in several animal models,


and results indicate these observed behavioral changes are likewise mediated by d-MPH, whereas l-MPH has little or no effect.

The contribution of the l-isomer to the overall pharmacological profile of the racemate remains unclear, owing to several studies suggesting that l-MPH may not be merely an inert isomeric ballast.


For example, behavioral studies conducted in rats demonstrate an attenuation (weakening) of the effect of d-MPH in animals pretreated with l-MPH,


suggesting that l-MPH may interfere with the action of the active enantiomer (d-amp). The importance of MPH chirality to central nervous system MPH receptor targeting has culminated in human


imaging studies revealing that d-MPH binds specifically to striatal structures, whereas l-MPH binding is nonspecific.


Taken together, data from in vitro, animal, and human studies support the premise that the d-enantiomer of MPH mediates the neurophysiological actions of MPH and therefore likely mediates its clinical efficacy.


http://www.ncbi.nlm....pubmed/18480678



Look at page 64 of the below link. it shows a PET image of the brain after focalin ingestion vs after ritalin ingestion

showing parts of the brain having higher activity while on focalin.
http://www.janetwatt....ntationpdf.pdf


the file has interesting facts about how diff release tech work in adhd meds

ritalin LA and focalin XR use the same sodas tech

That PDF link used to work, and links to a PET scan where it shows DexMPH working more effectively than MPH (at least in the brain scan).

try this one and go to page 64;

http://www.janetwatt...entationpdf.pdf

Edited by VoidPointer, 08 June 2010 - 05:55 PM.