Cocaine Dependence is clinically strikingly similar to amphetamine dependence but, although strong psychic dependence on cocaine occurs, neither tolerance to, nor physical dependence on, cocaine develops. Cocaine sensitizes adrenergic receptors by preventing the uptake of the catecholamines by the adrenergic nerves and by interfering with the degradation of the catecholamines by monoamine oxidase. Intoxication with cocaine causes signs of marked adrenergic stimulation. Cocaine has powerful excitant effects in the central nervous system that may also depend on changes in catecholamines.
There are two kinds of abuse of cocaine: the chewing of the coca leaf and the use of the pure alkaloid. Chewing of coca is limited to South America, where the coca leaves are masticated with lime. In the United States, the pure drug is used as a snuff or, more frequently, is taken intravenously in combination with heroin or morphine (“the speed ball”).
Clinical Manifestations About Cocaine Dependence :
Two kinds of signs and symptoms occur: those attributable to peripheral adrenergic stimulation include pupillary dilatation, sweating, tachycardia, gooseflesh, .hypertension, and increased temperature. The central nervous system manifestations are particularly marked if cocaine is taken intravenously. The users experience short-lived ecstatic sensations and take injections at short intervals until their supply is exhausted or a toxic psychosis supervenes. As the dose is repeated, insomnia, anxiety, increased startle responses, and increased muscle stretch reflexes appear.
Finally, a paranoid psychosis with delusions and optical hallucinations ensues. Cocaine users frequently think that they are being watched by the police (“bull horrors”) and, in this state, are dangerous. When the effects become too frightening, users frequently take heroin or morphine as an antidote to the cocaine.
