Also known as Charlie, snow, coke, powder. See also Crack below.

Cocaine is a stimulant made from the leaves of the South American coca shrub. It comes in the form of a white powder, and normally costs in the region of £50 a gram. Cocaine use is becoming increasingly widespread throughout the UK, as is crack cocaine. It is a Class A drug under the Misuse of Drugs Act (1971). Dealing carries a maximum life prison sentence and unlimited fine, and possession can mean up to seven years in prison and a fine of £5,000.

In common with most other street drugs, users are rarely sold a pure form of cocaine. The drug is often cut with other cheaper drugs such as amphetamines (speed), talc or detergents which can be poisonous or cause irritation, leading to infection, particularly if injected.

Usually snorted into the nose, it provides a feeling of excitement, exhilaration and self-confidence lasting for about 15-30 minutes. Cocaine can also be rubbed into the gums, onto the teeth and into the anus or vagina before penetrative sex. Cocaine and crack can also be made into a solution for injection. Users will frequently take repeated doses to maintain the high and as a result over a few hours anxiety, agitation and paranoia can develop, as well as tolerance for the drug, leading to the need for higher doses. Due to the short acting nature of cocaine, people who inject risk doing considerable damage to their veins due to the need to inject more frequently. Users are often tempted to step up the dose because of the feelings of physical and mental well-being produced by the drug.

After stopping use, users will feel tired, sleepy and depressed, which reinforces the temptation to repeat the dose.

With regular use, increasingly unpleasant effects develop which generally persuade people to 'give it a break'. Happiness is replaced by an uncomfortable state of restlessness, excitability, sickness, sleeplessness and weight loss. With continued use this may change to a persecuted state of mind. Regular users may seem nervous, excitable and suspicious. Confused exhaustion due to lack of sleep is common. All these effects generally clear up once the drug is stopped.

Repeated sniffing damages the nose membranes and may damage the structure separating the nostrils. The effect of cocaine use on diet and sleep means that women who are regular users of the drug may experience irregular periods. Cocaine also affects unborn children in several ways (www.marchofdimes.com/professionals)

• It may be linked to spontaneous abortion.
• Cocaine is expelled from the mother's body far more quickly than from the foetus.
• Women who use cocaine during pregnancy are more likely to deliver prematurely.
• Frequent users of cocaine are more likely to suffer a difficult delivery.
• The babies of cocaine users are more likely to be of low birth weight.
• Babies of women who use cocaine during pregnancy are much more likely to die after birth than babies of non-users, probably due to low birth weight and premature delivery.
• Children of cocaine users are likely to display jittery and disturbed behaviour during the first year of life, but there is no clear evidence that children of cocaine users will be less intelligent, have more severe behavioural problems or suffer retarded growth in later years.

All these apply to the babies of crack cocaine users too.

There is increasing evidence that sharing snorting equipment may permit the transmission of hepatitis C virus. Rubbing cocaine into the gums, vagina, or anus can cause ulceration, which could increase transmission of HIV or other sexually transmitted infections. Sharing injecting equipment also presents a risk for transmission of HIV, hepatitis viruses, and other blood-borne infections (www.nida.nih.gov/ResearchReports/Cocaine).