8. COCAINE

Cocaine is an alkaloid of the coca shrub and exhibits anaesthetic, vasoconstrictor and central stimulant properties. It has effects on a number of neurotransmitter systems in the brain and is active at many anatomical sites within the central nervous system.

Cocaine is prepared from the coca plant and initially is in the form of a salt (cocaine hydrochloride). This salt can be inhaled into the nostril and absorbed into the bloodstream across the nasal mucosa.

The cocaine salt can also be converted to the free base of cocaine with volatile solvents which must then be carefully removed. The free base cocaine is then burnt with inhalation of the smoke resulting in very rapid and efficient absorption across the alveolar membranes of the lungs.

The third method of cocaine administration is intravenous injection of the cocaine salt.

It is generally considered that most cocaine users begin with intra-nasal administration and later progress to injecting use or inhalation of smoke.

Cocaine was only discovered in Western Europe in the 19th century but had been used for centuries by South American Indians. In the past two decades consumption of cocaine has increased in America, Western Europe and more recently in Australia.

In the mid-1980s ready made free base cocaine was marketed in the streets of American cities and became known as 'crack'. Crack, a much cheaper and more accessible version of cocaine, is widespread among lower socioeconomic groups particularly in the inner-city areas dominated by racial and ethnic minorities in the United States of America. In contrast, the users of the crystalline form of cocaine, which is inhaled, have generally been identified as those who are better educated and of a higher socioeconomic status. These socioeconomic differences, together with the different preparations of cocaine, pose problems when attempting to propose general treatment guidelines.

Fox and Mathews (1992) report that in the United States, 25 000 000 people have used cocaine at least once with 6 000 000 Americans admitting use within the previous month and 3 000 000 using the drug continuously. Furthermore, 10% of pregnant women admitted to cocaine use at least once in the antenatal period.

In Australia levels of use are much lower, with the Parliamentary Joint Committee on the National Crime Authority 1988-1989 reporting figures of 84 500 users in the past 12 months and 6640 regular users. Contrary to popular perception, patterns of cocaine use in Australia have remained relatively stable between the years of 1985 and 1991. This is probably a consequence of the relative lack of availability and expense of cocaine. The only group in Australia to show an increase in use, were women in their early twenties and early thirties (Fox and Mathews, 1992).

Cocaine is a highly addictive drug, although there is disagreement in the research as to whether cocaine produces physical withdrawal symptoms. In general, the research suggests that cocaine does not produce physical dependence and a withdrawal syndrome.

Generally, regular users of cocaine are a very small group in Australia and are largely confined to the more affluent groups in the cities. Those most at risk could include:

• those educated, most probably to university level
• higher socioeconomic status
  
• single young people
• women in their late twenties and thirties.

The intensity, and sometimes the nature, of cocaine's effects are governed by:

• Improved performance
• Increased confidence
  
• Increased energy
• Exhilaration
  
• Enhances physical and mental well-being
• Increased rate of respiration resulting in rapid shallow breathing
  
• Increased temperature
• Spasm of local blood vessels
  
• Enlarged pupils
• Cardiac arrhythmias
  
• Suppressed appetite
• Insomnia.

• Loss of coordination
• Tremors
  
• Dizziness
• Muscle twitches
  
• Severe agitation
• Confusion
  
• Paranoid symptoms
• Headaches
  
• Cold sweat
• Pallor
  
• Nausea and vomiting
• Weak, rapid pulse
  
• Anxiety reaction.

• Heightened reflexes
• Muscle twitching
  
• Increased pulse rate
• Loss of appetite
  
• Insomnia
• Cardiac arrhythmias including malignant arrhythmias
  
• Angina
• Myocardial infarction
  
• Cocaine psychosis – paranoid delusions, auditory and visual hallucinations
• Tactile hallucinations
  
• Violent or aggressive behaviour
• Decreased libido/impotence.

Deaths from cocaine usually result from high sensitivity to the drug or massive overdose. Deaths from overdose may occur regardless of route of administration. In most cases the reported lethal dose of pure cocaine is approximately 1.2 grams to 1.4 grams. Most common causes of death are: