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Providing straightforward information pertaining to drugs, drug use & drug policy. The Grey Pages promotes drug-related literacy and advocates a system of viable and tolerant drug policies. This is my personal collection of commentaries, essays, tid-bits, and other such writings on everything ranging from drug use, drug policy and drug-myths, to drug-science, addiction, human behavior, and the workings of the human brain. I started this blog with a particular focus on opioids, and over the past year have found my interest gravitate toward the intriguing, ever-changing world of designer intoxicants (i.e. "research chemicals" or "designer drugs").

Monday, February 21, 2011

Piperidines

Methylphenidate (i.e. Ritalin, Concerta, Methylin)

Methylphenidate Molecule

Methylphenidate is a widely used psychostimulant best known by its trade name Ritalin. It can be chemically classified as a substituted phenethylamine. It shares structural similarities with amphetamine while its pharmacology is similar to cocaine (though it is longer acting).

Methylphenidate acts as a catecholamine transporter ligand. It alters the function of these transporters to, directly and indirectly, increase synaptic concentrations of dopamine and norepinephrine in areas of the brain. Methylphenidate is a strong dopamine-norepinephrine reuptake inhibitor, with the dextrorotatory enantiomer showing the most activity; binding affinities (Ki) and inhibitory constants (IC50) for racemic methylphenidate and dextromethylphenidate are as follows - Note that a lower value signifies greater pharmacological activity:

d-methylphenidate
DAT Ki: 161
DA IC50: 23
NET Ki: 206
NE IC50: 39

Methylphenidate (Racemic)
DAT Ki: 121
DA IC50: 20
NET Ki: 51
NE IC50: 788

Effects are similar to other stimlants and include wakefulness, increased alertness & energy, improved motivation, exhileration, excitement and euphoria.

Methylphenidate is used in the US in the treatment of ADHD, postural orthostatic tachycardia syndrome and narcolepsy. It has also been taken off label to alleviate severe cases of depression, obesity, chronic fatigue and lethargy. The drug is taken orally in tablet or capsule form and available as a branded or generic product from multiple manufacturers. Trade names include Ritalin, Concerta and Methylin. 

Ethylphenidate

Ethylphenidate is an analogue of methylphenidate. Its pharmacodynamic profile is similar, though it exhibits a higher selectivity for the dopamine transporter. This compound is formed when methylphenidate is taken along with alcoholic beverages.

Effects are similar to other stimlants and include wakefulness, increased alertness & energy, improved motivation, exhileration, excitement and euphoria.

2-DPMP

2-DPMP Molecule
2-DPMP is a potent stimulant of the pipradol family. It is alternately known by its chemical name 2-diphenylmethylpiperidine, or desoxypipradol.

Developed by the pharmaceutical company Ciba (now known as Novartis) in the 1950's and researched as a clinical stimulant for the treatment of ADHD. Research and development on this drug was dropped once methylphenidate was developed by the same company.

Its main mode of action is as a norepinephrine-dopamine reuptake inhibitor and its pharmacology is similar to methylphenidate.

Related to pipradol, diphenylprolinol, and methylphenidate.

2-DPMP seems to be active in most users in the 2 to 5 mg range. One dose can easily last throughout the day.

Compared to methylphenidate, its effects last longer and its pharmacokinetic profile is less consistent.

Strong tendency to produce paranoia, anxiety, and amphetamine-like psychosis. These characteristics are
2-D Structure of Pipradol (parent
drug for 2-DPMP)
 shared by its distant relatives of the N-pyrrolidinyl substituted cathinone family, specifically MDPV and a-PVP. 

Users report that this compound is unforgiving with excess dosing, and that excessive doses are quite easily administered accidently, especially in the absence of precision measuring equipment.

Due to its extended duration of action, dose accumulation has been a major issue. Re-dosing too soon will more than likely produce an unpleasant experience.

Reports of users staying up for days at a time while binging are not uncommon.

Noteable adverse effects include paranoia, anxiety, myoclonus, psychosis, hallucinations, delerium due to lack of sleep, and a state of prolonged agitation lasting days after use.


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