لخّصلي

Drug misuse is the improper use of common medications in ways that lead to acute and chronic toxicity.Physiologic dependence: is due to biochemical changes in body tissues, especially the nervous system.Laxatives, antacids, vitamins, headache remedies, and cough and cold medications are often self-prescribed and overused.Illicit drugs are of two types: (a) drugs unavailable for purchase under any circumstances, such as heroin, and (b) drugs normally available with a prescription that is being obtained through illegal channels.The two types of dependence, physiologic and psychologic, may occur separately or together.Psychologic dependence: is emotional reliance on a drug to maintain a sense of well-being, accompanied by feelings of need or cravings for that drug.Drug habituation: means a mild form of psychologic dependence.

Drug misuse is the improper use of common medications in ways that lead to
acute and chronic toxicity. both OTC drugs and prescription drugs may be
misused. Laxatives, antacids, vitamins, headache remedies, and cough and cold
medications are often self-prescribed and overused.
Drug abuse: is the inappropriate intake of a substance, either continually or
periodically. Drug abuse has two main aspects, drug dependence and habituation.
Drug dependence is the reliance on or need to take a drug or substance. The two
types of dependence, physiologic and psychologic, may occur separately or
together.
Physiologic dependence: is due to biochemical changes in body tissues, especially
the nervous system. These tissues come to require the substance for normal
functioning.
Psychologic dependence: is emotional reliance on a drug to maintain a sense of
well-being, accompanied by feelings of need or cravings for that drug.
Drug habituation: means a mild form of psychologic dependence. The individual
develops the habit of taking the substance and feels better after taking it.
Illicit drugs, also called street drugs, are those sold illegally. Illicit drugs are of
two types: (a) drugs unavailable for purchase under any circumstances, such as
heroin, and (b) drugs normally available with a prescription that is being obtained
through illegal channels. Illicit drugs often are taken because of their mood-
altering effect; that is, they make the user feel happy or relaxed.
Actions of Drugs on the Body
The action of a drug its half-life, the time interval required for the body’s
elimination processes to reduce the concentration of the drug in the body by one