I've been on dexedrine for 3.5 months now for adult ADD and find the
effects are not as strong as when I first started the medication. I
started with 40mg/day and am now at 50mg/day. The medication has
seemed to level off and I need to know if it is likely I will remain
where I'm at or is further tolerance inevitable or unlikley.Is long
term use of dexedrine typically possible?

Dear  Mitchy -

Thanks so much for trying Google Answers.  

Dexedrine, an amphetamine, is manufactured by SmithKline Beecham
Pharmaceuticals of Philadelphia.   Under regulations of the US Food
and Drug Administration  a manufacturers must cover a number of key
characteristics in the prescribing instructions of the drugs they
market.   One of these characteristics is the degree to which users of
the drug might become tolerant to it.

Tolerance is defined  at a well-respected online site as (1) "The
ability to endure unusually large doses of a drug..." and (2) a
"decreasing response to repeated constant doses of a drug or the need
for increasing doses to maintain a constant response."

"tolerance"
http://cancerweb.ncl.ac.uk/cgi-bin/omd?query=tolerance&action=Search+OMD

In the case of Dexedrine, the manufacturers state that "amphetamines
have been extensively abused. Tolerance, extreme psychological
dependence and severe social disability have occurred." They imply
that it is abuse of the drug--taking it in high doses, for
example--that may lead to tolerance.

Certainly, a slight increase in the dosage as you have taken could not
be considered "abuse."

There is another section of the prescribing instructions that should
be noted. Under "Drug Interactions" it is stated that certain
substances decrease the absorption (or increase excretion) of
amphetamines.  One of the more common of these substances is fruit
juice. It is a possibility that your need to slightly increase your
dose of Dexedrine is in response to the ingestion of fruit juices (or
other acidifying agents as listed under "Precautions Drug
Interactions)

 "Drug Interactions
Acidifying agents—Gastrointestinal acidifying agents (guanethidine,
reserpine,
glutamic acid HCl, ascorbic acid, fruit juices, etc.) lower absorption
of amphet-amines.
Urinary acidifying agents (ammonium chloride, sodium acid phosphate,
etc.) increase the concentration of the ionized species of the
amphetamine
molecule, thereby increasing urinary excretion. Both groups of agents
lower
blood levels and efficacy of amphetamines."

The complete prescribing information is found at:

Prescribing Information Dexedrine
us.gsk.com/products/assets/us_dexedrine.pdf  

NOTE: the above is a pdf file.  If you prefer an html file, the same
info in htm is dound at:

Prescribing Information Dexedrine
http://216.239.51.100/search?q=cache:iE8f4973GqEC:us.gsk.com/products/assets/us_dexedrine.pdf+%22smithkline+beecham%22+dexedrine&hl=en&ie=UTF-8

I hope this information has been helpful to you. As I'  sure you
agree, it should never be considered a substitute for discussing your
concerns with the physician who precribed Dexedrine for you in the
first place.

Good luck to you.

Alanna

search terms: dexedrine tolerance "rescribing information"
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=utf-8&q=DEXEDRINE+TOLERANCE+%22+%22prescribing+information%22&btnG=Google+Search

Hi alanna-ga.Thanks for your answer. I have recently found out that
tolerance to amphetamines can develope at small doses and are not
necesserally the result of only abuse. Please write back if you have
further imformation. mitchy-ga