Cocaine is a powerful stimulant of the central nervous system that interferes with the reabsorption process of dopamine, a chemical messenger associated with pleasure and movement. The buildup of dopamine causes continuous stimulation of neurons "receptor", which is associated with the euphoria commonly reported by people who abuse cocaine.
Physical effects of cocaine include constricted blood vessels, dilated pupils and increased body temperature, heart rate and blood pressure. The duration of immediate euphoric effects of cocaine (which include hyperstimulation, alertness and decreased fatigue) depend on the method of administration. The faster the absorption, the more intense the high but the shorter duration. The high can last from 15 to 30 minutes if inhaled cocaine, and 5 to 10 minutes if smoked. An increase in cocaine use can reduce the time period of euphoria in the user and increase the risk of addiction.
The Muscle Experiment
Some people who use cocaine report feelings of restlessness, irritability and anxiety. May develop tolerance to the high and there are many addicts who report trying in vain to get the drugs they produce the same pleasure as they did the first time I used it. Some users will increase their doses to intensify and prolong the euphoric effects. So as you can develop tolerance to the euphoria, some users also may become more sensitive to anesthetic and convulsant effects of cocaine. This increased sensitivity may explain some deaths occurring after apparently low doses of cocaine.
Episodes of sustained and repeated use of cocaine, higher and higher doses can lead to a state of increasing irritability, restlessness and paranoia. This can result in a period full of paranoid psychosis in which the user loses touch with reality and experiences auditory hallucinations.