Cocaine has enormously devastating side effects which can eventually be fatal. It acts extremely rapidly and its short term side effects can even be experienced by a person who has used it just once. Its long term side effects gradually show up after repeated use, and their intensity depends upon the duration and quantity of use.

The short term side effects of cocaine, although not always harmful, have occasionally been known to cause grave harm. Some of these are:
Increase in blood pressure
Contracted blood vessels
Dilated pupils
Heightened mental alertness
Boosted energy levels
Increase in heart rate
Reduced appetite
Increase in body temperature

The feeling of increased energy is what hooks first time cocaine users to the drug. It gives them a quick rush, more energy, less need for sleep and heightened physical endurance. This temporarily increases their productivity at work and in other areas of their daily lives. However, what they overlook is the fact that with continued use, their bodies are increasing their tolerance with respect to cocaine and thus becoming more and more dependent on it. Although the results may seem positive at first, this dependency causes addicts to make harmful life choices later.

People, who are keen to lose weight and look thin, are often attracted to cocaines ability to reduce appetite drastically. Users are often able to go for days without any food and this pattern of behavior only strengthens the addiction.

As cocaine abuse continues, and tolerance grows, the long term side effects of the drug begin to surface. Some of the most detrimental medical conditions that are caused by cocaine abuse are heart disease, respiratory failure, strokes, seizures, convulsions, nausea, fever and coma among several others.

Harmful life choices such as lying, cheating, stealing and being absent from work begin to be made by users as dependency increases. These effects are not directly due to cocaine use but rather due to the lifestyles of cocaine addicts. Users are also known to have violent and erratic behavior patterns.

Other long term effects of cocaine use are:
Addiction
Paranoia
Irritability
Restlessness
Auditory hallucinations
Mood disturbances

Long term cocaine use increases tolerance to the drug. Hence, users need higher and higher uses to feel the high that they did during the initial stages. However, the high is never really the same as the first time and this vicious addiction can even lead to death.