What is an Amphetamine?
Amphetamine, also known as ‘speed,’ is a synthetic stimulant used to suppress the appetite, control weight, and treat disorders like narcolepsy and attention-deficit hyperactivity disorder (ADHD). It is sometimes also used recreationally and for performance enhancement, but these uses are illegal in most countries.
Amphetamines cover several similar substances including amphetamine sulphate, methamphetamine and dexamphetamine. Amphetamines are produced from an oil base but may be found in a number of forms. The most common is for the oil to be converted into a powder form. This may be made into tablets or capsules.
Amphetamine Treatment and usage:
Amphetamine is a synthetic compound with strong stimulant effects. In the US, it is most often used to treat attention-deficit hyperactivity disorder (ADHD) and narcolepsy, but is also approved as a weight-loss medication in certain cases of obesity and for treatment-resistant depression. Within the armed forces only, it is also prescribed as an anti-fatigue pill for pilots and other individuals in situations requiring alertness. Amphetamines are also used illegally to gain these effects. The desired effects predominantly come from d-amphetamine (l-amphetamine contributes to the unwanted peripheral side effects).
Amphetamine Method of action:
The mechanism of action of amphetamines includes four major methods in the body for producing its effects.
The neurotransmitters dopamine, serotonin and noradrenalinare released from their nerve terminals. The release of dopamine by amphetamine is associated with the reversal of the neuronal membrane uptake transporter. Monoamine oxidase activity is inhibited, as well as neurotransmitter re-uptake. And finally, amphetamines work by taking direct action on neurotransmitter receptors themselves.
Amphetamines are absorbed from the small intestine. The peak plasma concentration occurs in 1-2 hours after ingesting amphetamines. Absorption is normally complete in 2.5 – 4 hours and is increased by food consumption. Amphetamine metabolites are excreted in urine.
The general effects of amphetamines are variable, and determined by the amount taken, the user’s past experience with the substance, the manner in which the drug was taken, the circumstances under which the amphetamine was taken, the setting in which it was taken, the patient/user’s psychological and emotional state, and the simultaneous use of alcohol or other drugs.
Warnings or dangers associated with Amphetamines:
Tolerance to the “anorectic” effects of the drug may develop. If this occurs, the recommended dose should not be exceeded in order to increase the effect, rather, the drug should be discontinued at this point.
Patients with even mild hypertension should be prescribed amphetamines with caution. The least amount feasible should be dispensed at one time in order to minimize the possibility of overdose. Amphetamines may impair a patient’s ability to operate machinery or vehicles; therefore, caution should be taken accordingly.
Amphetamines may cause a significant elevation in plasma corticosteroid levels, greatest in the evening. As well, they may interfere with urinary steroid determinations. Amphetamines should only be prescribed and used during pregnancy when the potential benefit justifies the potential risk to the unborn child. It is unknown whether amphetamines are excreted in breast milk, but because many drugs are, caution is advised when amphetamines are administered to nursing women.
Tolerance develops quickly in amphetamine use, and the risk of addiction is relatively high.
The most common side effects when taking Amphetamines include elevation of blood pressure, palpitations, tachycardia, overstimulation, restlessness, dizziness, insomnia, euphoria, dyskinesia, dysphoria, tremor, yawn, headache, exacerbation of motor and phonic tics and Tourette’s syndrome, dry mouth, unpleasant taste, diarrhea, constipation, anorexia, weight loss, and changes in sex drive (libido) including impotence in men and anorgasmia (inability to reach orgasm).
Amphetamine Overdose and withdrawal:
Amphetamine sulfate is a Schedule II controlled substance, and has been extensively abused. Individual response to amphetamine use varies widely. While toxic symptoms sometimes occur as an idiosyncrasy at doses as low as 2mg, they are rare with doses of less than 15mg. Thirty mg can produce severe reactions, yet doses of 400 to 500mg are not necessarily fatal.
Symptoms of Amphetamine overdose include tremor, restlessness, hyperreflexia, rapid breathing, confusion, assaultiveness, hallucinations and panic. Fatigue and depression usually follow the central stimulation. Cardiovascular effects include hypertension, hypotension, circulatory collapse and arrhythmias. Gastrointestinal effects reported include vomiting, nausea, diarrhea and abdominal cramping. Fatal poisoning is usually proceeded by convulsions and vomiting.
Precautions with Amphetamines in children and the elderly:
Amphetamine use in older adults has not been well studied or established, however there may be some indication for prescribing amphetamines to elderly patients with narcolepsy.
Long-term amphetamine use has not been well-established in children. While some reports have shown improvement in ADHD children with the use of amphetamines, there is still some caution advised due to the drugs’ powerful effects and risk for addiction and abuse.