DRUGS OF ABUSE-PART-V-COCAINE

COCAINE

Cocaine is a potent drug of abuse to produce hallucinogenic and dissociative anesthesia. It is used as a local anesthetic and because of its potent abusive and addictive stimulant effects, it is largely replaced by lignocaine.

Cocaine was first extracted from the leaves of Coca a native plant of South America.

 Chemically it is an alkaloid and can act with strong acids to form salts. The chloride salt formed by the reaction with Hydrochloric Acid is most common as it is water-soluble and can be injectable.

Snuffing cocaine as a base is producing more hallucinogenic effects and is more toxic.

Cocaine can be taken by snuffing by nasal inhalation, swallowed through oral routes, and by intravenous injection. Snuffed cocaine produces more side effects because of the byproduct known as Methyl Ecgonidine that can cause more side effects like cardiovascular effects, myocardial infarction, and pulmonary effects than cocaine taken by other routes.

Mechanism

Cocaine is a powerful CNS stimulant. Its mechanism of action is by blocking the reuptake of the powerful stimulant neurotransmitters such as norepinephrine, dopamine, and 5-hydroxy tryptamine by the presynaptic nerve terminals. Hence the concentration of these transmitters increased at the synaptic space followed by powerful stimulant receptor responses.

Physiologic Effects

1.Mydriasis (Dilatation of the pupil)

2.Positive Chronotropic Effect (Elevated Heart Rate)

3.Alertness

4.The feeling of good confidence

5.Euphoria by the stimulation of the limbic area of the brain which is situated around the thalamus and responsible for emotions, behavior, motivation, and long term memory.

Metabolism and Kinetics

Cocaine is largely metabolized by the liver to the potent toxic benzoylecgonine(BE), and to a lesser extent to ecgonine methyl ester (EME) and ecgonine. Less than one percent is left unchanged. All of them are finally excreted by the kidneys.

Overdose Effects

1.Excitation

2.Hallucinations 

3.Psychoses

4.Respiratory Depressions

5. Coronary vascular blocks followed by arrhythmias.

6.Myocardial Infarction.

7.Liver and Kidney damages

8.Coma and Death.

Clinical Uses

Cocaine is restricted to use as a vasoconstrictor during ENT surgical procedures.