Stimulants amphetamine ephedrine cocaine and caffeine

Substances belonging to this group range from the potent amphetamines to the weaker caffeine and ephedrine. The substances are called sympath-omimetics and imitate the effects of the stress hormones epinephrine and norepinephrine. Amphetamines were synthesized first in 1887 and were initially commercially available as a nasal decongestant. They cause the release of excitatory neurotransmitters, such as dopamine, to stimulate the central nervous system (CNS). The main effects on the CNS include wakeful-ness, alertness and a decreased sense of fatigue, mood elevation, increased self-confidence and a decreased appetite. The physical effects include increased heart rate, redirection of blood flow from the gastrointestinal tract to the muscles, and an increased fat metabolism. Amphetamine carries a high potential of tolerance, i.e. dosage has to be increased after prolonged use to induce the same effect. Although several CNS-acting stimulants are suspected to be performance enhancing, amphetamine is among the few that has been evaluated scientifically and has been shown to improve performance by 3-5% [1]. Ephedrine's effect on the CNS is weaker than that of amphetamine and controlled studies on its effect are few. Evidently ephedrine has an energy expenditure enhancing effect which has been used in treatment of obesity, and thus could potentially—although this is unsubstantiated— lead to fat loss in athletes. Cocaine has not

Table 2.5.1 Overall effect of ergogenic agents and procedures. Substances above the full line represent abandoned doping substances, whereas procedures and substances below the line represent legal or limited-legal approaches (caffeine below the allowed limit).

Substance

Mechanism and effect

Blood doping

Hgb and V o2max(10-15%)

Erythropoietin

Hgb and V 0^(10-15%)

Anabolic steroids

Protein synthesis and strength (10-30%)

GH/IGF-I

Protein synthesis and strength (?)

Beta-adrenergics

Protein synthesis and strength (5%)

Beta-blockers

Central (5-10%)

Amphetamine

Central (3-5%)

Altitude

Hgb and V O2max(3-6%)

Caffeine

Metabolism (5-15%), contraction (2-4%)

Creatine

Metabolism (3-5%), strength (10-20%)

Bicarbonate

Neutralize acidosis (3-4%)

GH,growth hormone; Hgb,hemoglobin; IGF-I,insulin-like growth factor 1.

Table 2.5.2 Chain of events finally leading to the banning of drugs in sport and the establishment of the independent World Anti-Doping Agency (WADA).

1896

The first recorded death was in 1896 when a cyclist,Arthur Linton, collapsed and died after finishing the first ever Paris Roubaix apparently after an overdose of strychnine

1904

The first near death in modern Olympics where a marathon runner,Thomas Hicks,was using a mixture of brandy and strychnine No specific date

Most drugs involved alcohol and strychnine. Heroin, caffeine and cocaine were also widely used until heroin and cocaine became available only on prescription

1930s

Amphetamines were produced and quickly became the choice over strychnine.A wide use of amphetamine among soldiers was seen during the Second World War

1950s

The production and use of synthetic testosterone explains the extreme improvements in weight-lifters from the Soviet team at the World Championship in 1954.Accordingly the potent effect of testosterone and synthetic derivatives such as dianabol became common knowledge

1952

One of the first noticeable doping cases involving amphetamines, which occurred at the Winter Olympics. Several speed skaters became ill and needed medical attention

1960

At the Olympics in Rome, Danish cyclist, Kurt Jensen, collapsed and died from an amphetamine overdose

1963

The Council of Europe set up a Committee on drugs but couldn't decide on a definition of doping.The first ever antidoping law was approved in France and 2 years later in Belgium

1966

The first doping controls were carried out by FIFA during the World Championship in soccer in England

1967

The IOC took action after the death of Tommy Simpson (due to the illegal taking of amphetamines) in the Tour de France

1968

The IOC decided on a definition of doping and developed a banned list of substances.Testing began at the Olympic games

1988

At the Seoul Olympics, Ben Johnson tested positive for a banned anabolic steroid, was stripped of his gold medal and was suspended for 2 years

1999

The World Conference on Doping in Sport held in Lausanne on 2-4 February 1999 produced the Lausanne Declaration on Doping in Sporf.This document provided for the creation of an independent international antidoping agency to be fully operational for the Games of the XXVII Olympiad in Sydney. Pursuant to the terms of the Lausanne Declaration,the World Anti-Doping Agency was established on 10 November 1999 to promote and coordinate the fight against doping in sport internationally been found to have any performance-enhancing effect in athletes. Although this drug could contribute to a subjective feeling of 'doing well', the effects on peripheral reflexes of cocaine could in fact impair performance.

The effect on the CNS of amphetamine may lead to a distortion of the user's perception of reality and impairment of judgement, which may cause an athlete to continue participation while injured or exhausted leading to worse injuries or collapse. Other acute side-effects are headaches, insomnia, convulsions, halluci-

nations and paranoia and ultimately death due to ruptured blood vessels in the brain, heart attacks, heart rhythm abnormalities and heat stroke. Chronic side-effects consist of dyskinesia, compulsive and repetitive behaviors, schizophrenia and death from ruptured blood vessels throughout the body.

Caffeine, even in moderate doses (5-6 mg/kg body weight) that do not exceed the accepted amount of caffeine in the urine, will result in improved performance. Earlier results indicated that the primary effect of caffeine was to stimulate an increase in circulating

Table 2.5.3 Performance-enhancing drugs.

Performance aim

Ergogenic agent or method

Effect

Endurance

Erythropoietin Blood doping Hemopure/oxyglobin Caffeine

5-15%

Strength (Body composition)

Anabolic steroids Growth hormone Insulin-like growth factor 1 Beta-adrenergic

10-30%

Central fatigue Restitution (Nervousness) (Pain)

Amphetamine

Ephedrine/cocaine

Beta-blockers

ACTH/cortisol

Local anesthetics

Glucose/insulin

Alcohol

3-5%

Probenecid/epitestosterone Human choriogonadotrophin Saline infusion

Table 2.5.4 The IOC list of prohibited classes of substances and methods.

I Prohibited classes of substances A Stimulants

B Narcotics C Anabolic agents D Diuretics

E Peptide hormones, mimetics and analogs

II Prohibited methods A Blood doping

B Pharmacologic,chemical and physical manipulation

III Classes of substances prohibited in certain circumstances A Alcohol

B Cannabinoids

C Local anesthetics

D Corticosteroids

E Beta-blockers catecholamines which in turn mobilized free fatty acids (FFA) from adipocytes and improved muscular fat metabolism, sparing glycogen stores and improving endurance performance . However, more recently it has been shown that other mechanisms are also active, in that an enhanced performance effect of caffeine can be demonstrated in the absence of changes in cate-cholamines, and is found even in sports lasting only 5-30 min where fat metabolism does not play any major role. The effect has also been demonstrated in vivo in spinal cord injured individuals who underwent electrical stimulation of paralyzed muscle indicating that effects were local on the muscle rather than related to the brain, epinephrine or fatty acid mobilization [2].

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