Posted by 3 Beer Effect on April 30, 2002, at 1:06:42
I found some interesting info on the differences in action between the Amphetamines: [Dexedrine/Dextrostat (d-amphetamine), Adderall] & Methylphenidate: [Ritalin, Concerta, & Focalin=d-ritalin] from the excellent book "GOODMAN and GILMAN's The Pharmacological Basis of Therapeutics."
"The reinforcing & euphorigenic effects of amphetamine, methyphendiate, & cocaine appear to involve potentiation of the actions of catecholamines in the CNS, especially those of dopamine. Furthermore, amphetamine facilitates electrical self-stimulation of "reward" areas of the brain"- which makes boring or repetitive work or study of subjects you dislike more interesting/engaging/fun.
Amphetamine is primarly a dopamine/norepinephrine RELEASER of stored or newly synthesized dopamine & norepinephrine & a bit of serotonin especially at high doses, although at higher doses it also inhibits the reputake of dopamine & norepinephrine (but not as much as methylphenidate or cocaine).
"At oral doses of 10 to 30 mgs amphetamine causes increased wakefullness, alertness, elevation of mood, initiative/drive, self-confidence, ability to concentrate, athletic ability & strength, increased motor & speech activity & often elation & euphoria".
Amphetamines (Dexedrine/Dextrostat, Adderall) but NOT Ritalin or Cocaine are dependent on the rate limiting ability of tyrosine hydroxylase to turn l-tyrosine into l-dopa which is the first step in dopamine/norepinphrine/epinephrine production. So Lithium & possibly other mood-stabilizing drugs or any other drug that inhibits tyrosine hydroxylase (or a diet deficient in l-tyrosine) blocks/diminishes the stimulating actions of Amphetamine but not Ritalin or Cocaine.
The absorption & effects of Amphetamines are also dependent on the ph of the stomach & the urine. An alkaline agent such as Baking Soda (dissolved in water) increases the absorption of amphetamines in the stomach, and baking soda in higher doses makes the urine alkaline, greatly slowing the elimination & thus prolonging the duration & effects of amphetamines (although taking baking soda for this effect is supposed to be pretty bad for your health- Your body constantly tries to find a ph equilibrium, in both the stomach & especially in the blood which is neutral in ph except with severe dehydration or serious health problems). Acidic agents/food/drinks such as certain fruit juices decrease the duration & effect of amphetamines (thus it is better to drink water with Adderall/Dexedrine instead of fruit juice or Colas).
Ritalin is unaffected by these acid/alkaline food/drink restrictions but unlike amphetamines, its absorption is greatly reduced when there is food in the stomach. It extent of absorption differs radically in different people, between 30 to 70% is absorbed.
Amphetamines taken on a full stomach are absorbed to the same extent but the time to peak blood level is increased, so the effects won't feel as 'powerful'.The length of time to peak blood level makes a drug feel subjectively strong or weak. The same dose of Amphetamine or Ritalin taken intranasally will feel much stronger giving a "flash" or "high" (described as akin to an orgasm in the brain) since it only takes about 7-11 minutes to reach the brain but will be eliminated much faster & tolerance/dependence will develop much more quickly than an oral dose. Oral Ritalin peaks in the brain at a little over an hour, Dexedrine at about 2 hours, & Adderall about 3 hours.
Adderall is a longer acting mixture of dextroamphetamine & amphetamine in a 3:1 ratio. "In elicitation of CNS excitatory effects the d-isomer (dextroamphetamine/dexedrine) is 3 to 4 times as potent as the l-isomer (amphetamine)". The l-amphetamine or d,l amphetamine sulfate is more potent than dextroamphetamine in eliciting cardiovascular effects. (I've found Dexedrine to be kind of similar to Ritalin in increasing mental stimulation, but Adderall seems to be better at getting you out of bed or for all night or multiple day cram sessions).
Ritalin & Cocaine are kind of like the SSRIs of dopamine, in that they mainly inhibit or block the reuputake of dopamine & to a lesser extent norepinephrine in a dose related manner. Ritalin is supposedly halfway between Caffeine & the amphetamines in potency. 20 mg of Ritalin is said to equal to 10 mg of Dexedrine. But it has also been said that an if an equal dose of Ritalin & Amphetamine are given, Ritalin produces greater mental stimulation & also is more effective at increasing blood flow to certain parts of the brain necessary for higher though, retention etc.
For me personally, i've noticed that in normal oral ADD doses, Dexedrine or Adderall are social disinhibitors when you are among other people- they increase your self confidence & you'll basically talk someones ear off, while Ritalin seems to be a social inhibitor where you care more about studying than socializing & causes more anxiety in social situations- Experiments with Rats had the same outcome.
One thing is for sure, & a fact I can personally attest to is that all three of these drugs Adderall, Dexedrine, & Ritalin are very potent stimulants.
Back in my days of stimulant abuse, I noticed that high doses of intranasal Ritalin felt very similar & gave nearly the same 'high' as the 'cut' powder Cocaine bought on the street in the USA with the exception that you nose doesn't become numb- but I did try uncut Cocaine in Mexico & that was a whole different story, i'm lucky I didn't have a heart attack(!) & the numbness & euphoria extended to the entire face & to a lesser extent all the way down to my legs.
Interestingly enough, 1 of the 4 components of Adderall called amphetamine sulfate (d,l) is known as Benzedrine & was taken off the market because of its widespread abuse in the late 1960s/early 1970s. With a high intranasal dose (60 mg +) Adderall or Dexedrine has a slight hallucinogenic effect & gives a rush of energy & euphoria known as the "flash".
Also, it is said that most users can't tell the difference between the stimulatory effects Methamphetamine (Desoxyn) & Dexedrine, & the subjective effects Amphetamines are indistinguishable from Cocaine even to experienced abusers if given (blindly)intravenously or intranasally (with the exception of the strong nasal numbing/local anasthetic effect of cocaine). Basically, the only real difference is that Amphetamines are cheaper & last much longer than Cocaine.
Any of these drugs, even Ritalin, in sufficient doses (75 to 90+ mgs of Dexedrine intranasally for example), often produce a paranoid state which is often indistinguishable from paranoid schizophrenia. This amphetamine 'overdose' syndrome is characterized by repetitive movements (sterotypy), delusions of grandeur or paranoia, hallucinations, teeth grinding, picking at the skin & face & sometimes violent outbursts. With enough of the drug on hand, a user can stay awake for days at a time, until he runs out or the inevitable need for sleep (the "crash") overpowers him.
On the other hand, Adderall, Dexedrine, & Ritalin differ from Cocaine & other physically addictive drugs in that when taken orally in proper amounts they are not addictive and may produce a pleasant, optimistic feeling but do not produce a "high".
In the high doses of abusers, they are psychologically but not physically addictive. A heavy Amphetamine or Ritalin abuser can stop cold turkey & will experience severe depression & a long period of sleep & lethargy but not physical withdrawl symptoms like convulsions, extreme nausea etc.
Ritalin & Cocaine are surprisingly similar in their method of action, but Ritalin clears from the brain much more slowly & so isn't anywhere near as reinforcing as Cocaine (which being the most potent 'natural' stimulant also has some physically addictive components). Also, prescription Amphetamines (with the possible exception of the street drug Crystal Methamphetamine) & Ritalin rarely cause death by overdose because of their weak effects on blood pressure. Cocaine & even the over the counter stimulant Ephedrine/Ephedra are much more toxic/dangerous in overdose. Cocaine overdoses have resulted in more emergency room admissions for Cocaine than all the other illicit drugs combined and Ephedrine/Ephedra has been linked to quite a few (I believe 80 or so in Texas alone) in the last 10 years.
Adults & teenagers who abuse these ADD psychostimulant medications can & do get psychologically addicted, which is why there is a big controversy about the validity of Adult ADD & is the reason for their Schedule II controlled status (in the same class as cocaine, methamphetamine (Desoxyn), the stronger morphine derivatives (Oxycontin, Percocet, Diladiud=known as "drugstore heroin" etc), & many barbituates).
Apparently ADD children are different in that they get dyshoria or a simple relaxed, 'focused' effect rather than euphoria from these psychostimulants & so almost never abuse them, & often compliance with their Adderall, Ritalin or Dexedrine medication regimen is a problem.
poster:3 Beer Effect
thread:104479
URL: http://www.dr-bob.org/babble/20020425/msgs/104479.html