Dextroamphetamine

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[[Image:{{{image\|Dextroamphetamine.png}}}\|{{{width\|220}}}px\|Dextroamphetamine chemical structure]] Dextroamphetamine
1-phenylpropan-2-amine IUPAC name
CAS number 300-62-9	}}}
PubChem 5826	DrugBank APRD00480
Chemical formula	C₉H₁₃N
Molecular weight	135.206 g/mol
Bioavailability	~25%
Metabolism	Hepatic
Elimination half-life	10-28 hours
Excretion	Renal: ~45%
Pregnancy category	C: (USA) B3: (AUS)
Legal status	Prescription only
Routes of administration	Oral

Dextroamphetamine (also known as dextroamphetamine sulfate, dexamphetamine, Dexedrine, Dextrostat, Dexampex, Ferndex, Oxydess II, Robese, Spancap #1, and, informally, Dex), a stereoisomer of amphetamine, is a potent central nervous system stimulant that induces the release of the neurotransmitters dopamine and (to a lesser extent) norepinephrine into nerve synapses in certain areas of the brain, thus promoting nerve impulse transmission. In the majority of individuals, dextroamphetamine acts as a psychostimulant, increasing mental alertness and decreasing any sense of fatigue.

1 Overview and History
2 Clinical uses
3 Side effects
4 Other uses
5 Dextroamphetamine and literature/music/film
6 References
7 See also

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Overview and History

Dextroamphetamine, commonly abbreviated as d-amphetamine, is the dextro isomer of amphetamine. Racemic amphetamine, which consists of equal parts dextroamphetamine and laevoamphetamine, was first synthesized under the chemical name "phenylisopropylamine" in 1887 by the Romanian chemist L. Edeleano. Amphetamine was not widely marketed until 1932, when the pharmaceutical company Smith, Kline, and French (currently known as GlaxoSmithKline, or GSK) introduced it in the form of the "Benzedrine Inhaler," for combating cold symptoms. Three years later, in 1935, the medical community became aware of the stimulant properties of amphetamine, specifically dextroamphetamine, and in 1937 Smith, Kline, and French introduced Dexedrine tablets, which consisted of pure dextroamphetamine sulfate (a dexedrine salt). In the United States, Dexedrine tablets were approved to treat narcolepsy, attention disorders, depression, and obesity. Dextroamphetamine was marketed in various other forms in the following decades, primarily by Smith, Kline, and French, such as several combination medications and, in the 1950s, an extended release capsule (the "Spansule").

It quickly became apparent that dextroamphetamine, as well as other stimulants such as methamphetamine, could be abused, though these medications were not heavily controlled until 1970, when the "Comprehensive Drug Abuse Prevention and Control Act" was passed by the United States Congress. This law, which most notably formed the Bureau of Narcotics and Dangerous Drugs--the precursor to the Drug Enforcement Administration, also placed many medications into one of five classifications, or "Schedules" according to their potential for substance abuse versus their medical utility. Dextroamphetamine, amphetamine, methylphenidate, and oral forms of methamphetamine were placed in schedule III of the Controlled Substances Act, while injectable methamphetamine resided in schedule II. All forms of amphetamines were later placed into the more restrictive schedule II category.

Dextroamphetamine is still widely prescribed today (see Clinical Uses, below), primarily as dextroamphetamine sulfate. Other forms of the drug include the popular ADD/ADHD medication Adderall and its generic derivatives which contain dextroamphetamine sulfate as well as dextroamphetamine saccharate (in addition to the sulfate and saccharate salts of racemic d,l-amphetamine). The saccharate and sulfate forms differ pharmacokinetically in the rate at which they are metabolized by the body.

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Clinical uses

Its only accepted indications are for children and adults with attention deficit hyperactivity disorder (ADHD) or well-established narcolepsy, generally where non-pharmacological measures have proved insufficient. In some localities it has replaced Ritalin as the first-choice pharmacological treatment of ADHD, of which it is considered an effective treatment. Dexedrine is contraindicated for patients with a history of substance abuse.

Certain studies have been performed regarding possible alternate uses for antidepressant treatment for HIV patients with depression and debilitating fatigue, early stage physiotherapy for severe stroke victims, and treatment for those with methamphetamine (speed) addiction. Dextroamphetamine is also used to treat fatigue in cancer patients. Even outside clinical trials, the drug may legally be prescribed for off-label use to treat these non-approved indications. Dextroamphetamine sulfate tablets are used by the military to combat drowsiness in fighter pilots.

The drug comes in 5mg and 10mg tablets, or tabs, as well as 5mg, 10mg, and 15mg Spansules (Capsules, or caps). The most commonly used bioavailable formulation of dextroamphetamine is dextroamphetamine sulfate, which is a salt of d-amphetamine.

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Side effects

Possible adverse effects of dexamphetamine include insomnia, reduced appetite, dependence, nervousness, restlessness, irritability, and euphoria that may be followed by fatigue and depression. There may be dryness of mouth, abdominal cramps, headache, dizziness, tremor, sweating, palpitations, increased or sometimes decreased blood pressure and altered libido. The Physician's 1991 Drug Handbook reports: "Symptoms of overdose include restlessness, tremor, hyperreflexia, tachypnea, confusion, aggressiveness, hallucinations, and panic."

There have also been reports of growth retardation of children with long-term use, although this effect can be reduced by alternating periods of abstinence from dexedrine.

As Dextroamphetamine is a stimulant, it is highly addictive and should be used with caution. The use of Dextroamphetamine for long periods of time may result in drug tolerance, and even physical dependence. Addiction is relatively uncommon when used as prescibed, such as in cases of attention deficit hyperactivity disorder and narcolepsy. However, the drug is also widely used without a prescription, and can be abused for its sleep-inhibiting properties.
Dextroamphetamine is a Schedule II controlled substance, and possession without prescription is illegal. This is due to the extremely high potential for abuse, as well as the severe physical and psychological effects that can result from this.

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Other uses

The US Air Force uses dextroamphetamine as its "go-pill," given to pilots on long missions to help them remain focused and alert. Other branches of the US military (as well as the armed forces of foreign nations) commonly use or have dispensed dextroamphetamine to troops to prevent or treat fatigue in combat situations. Because of the propensity of dextroamphetamine to cause behavioral side effects, this use is viewed as controversial; newer stimulant medications with fewer side effects, like modafinil are being investigated for this reason.

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