It is a downer that affects the brain's pleasure systems and interferes with the brain's ability to perceive pain. ... Cocaine is a powerful central nervous system stimulant that heightens alertness, inhibits appetite and the need for sleep, and provides intense feelings of pleasure. ... Stimulation of the central nervous system may cause tremors in the inexperienced user, or even convulsions with high doses. ... In general, chronic exposure to nicotine may cause an acceleration of coronary artery disease, peptic ulcer disease, reproductive disturbances, fetal illness and death. Toba...

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