The drugs that are addictive andJor often abused include very valuable substances that, taken in moderate doses that have been properly prescribed, relieve pain and produce sleep, but in large doses cause various physical and psychological effects, including stupor, coma and, commonly, convulsions. Among the habit-forming drugs are opium and its derivatives, cocaine, amphetamines and barbiturates.
One of the major issues regarding drug dependence refers to the question of why young people take such drugs. There appear to be three major reasons for doing so:
(1) To obtain something valued. For instance, to be accepted among their circle of friends (one of the main reasons for the epidemic quality of drug-taking), or to be awake, alert and lively, throughout weekend parties that may in themselves be a means of filling in time away from an unacceptable or unaccepting home.
(2) To remove discomfort or anxiety. For example, a person who is shy and lonely finds that he can overcome his handicap with the help of alcohol or amphetamines.
Another who is despondent or who has accepted social failure (especially with the opposite sex) may find temporary relief, a new identity, and at the same time may express, against himself, the resentment and aggression that frustration always produces (hence the seemingly self-destructive element of much drug-taking).
(3) To dispel boredom. All humans, especially the vigorous and intelligent young, have exploratory drives towards mastering things and towards new and exciting, even dangerous, experiences; in their words they seek “kicks.”
The problem is complicated by the varied effects of different drugs (not always the same in all people) and by the development of physical as well as psychological dependence. Thus, while drug-taking may be initiated in one way, it may be continued for quite different reasons.
One further general point concerns what is not known, and unfortunately the list is long. For example, we do not know the full extent of the problem that is, how many are flirting with drugs, not just the factors that “hook” the few.
In particular, we do not know about treatment of severe cases; doctors are good at getting patients “off the hook” but very poor in keeping them off -all the more reason for trying to prevent addiction, and for the cooperation of lay people in the aftercare of former addicts. Reflection on the above facts will suggest the principal ways of tackling the problem and where we, the general public, may help. Controlling sources of addictive drugs, law enforcement, the provision of treatment centers and research facilities are all of primary importance but are hardly our problems, except that, if responsible people repeatedly asked what was being done in these directions, there would be a powerful stimulus to getting something done, or getting something more done. The most important thing for lay adults to be, if they are to help, is inquisitive, because if they are truly inquisitive either about the problem as a whole or about particular young persons, they will become concerned. They will not act on preconceived or emotional judgements but will try to find out, and that means that communication will be two-way and therefore potentially useful.

We know that it is no use talking at young people, or trying to scare them by depicting horrific consequences, but if there is a real exchange of facts, opinions and feelings between two parties, or within a group, understanding and perhaps trust will have been gained on both sides and something practical may develop. In this way, if young people admit to or are reported as misusing drugs, or if their erratic and variable behavior (their unhappiness and irritability, their exhaustion on Monday mornings, deterioration in their work, health and social relationships) suggests it, then we should begin thinking about the possible reasons as given here, and should make an opportunity to talk with them and to make plans with them. A high priority in the discussion will be whom to call in, and of course parents must first be considered, as well as school principals, priests, doctors or social workers. The majority of these cases, especially in the young, tum out to be based on familiar personal and family problems, directed into these new channels by unfortunate, but increasingly common, local conditions and opportunities. It is not quite such a new problem as may be supposed but it does need the active consideration and help of all responsible people, especially parents.

The great number of reactions of the skin to the administration of drugs warrants a separate discussion.

The skin is the organ most commonly affected by severe, undesirable effects of drugs, and this can occur by a variety of different mechanisms: rashes and the like, which follow the taking of drugs, are often classed as allergic, but it must be said that the evidence for allergy is frequently scanty.

Allergic reactions

In order to be able, with absolute certainty, to classify such a drug reaction as “allergic” it is essential to demonstrate that antibodies or immune-competent cells directed against an antigen have been formed from the drug or one of its metabolites, and since drugs usually consist of fairly small molecules, the allergen that causes this reaction will as a rule be a compound formed by the drug and tissue protein.

In practice, the diagnosis of an allergic skin reaction to a drug is made only in those who have previously received the drug in question on one occasion and have tolerated it, but who, on renewed treatment, develop skin lesions with or without general symptoms such as high fever. Such people may develop an allergic reaction without having received exactly the same drug previously: for example, taking one sulphonamide drug can readily cause allergy to other sulphonamides in those sensitive to them.

Anaphvlactic shock and nettle rash

These are caused by the formation of specific antibodies that become attached to tissue cells called mast cells. When an individual is again exposed to the drug, the allergen reacts with the specific antibodies, and histamines and other active substances are released from the mast cells and cause urticaria and, in some cases, a fall in blood pressure, spasms of the muscles of the bronchi (airways), and edema (swelling) of the larynx.

In severe allergy, a person can die within minutes from allergic - or anaphylactic - shock. In moderate forms of allergy, urticaria alone may occur.

Penicillin, aspirin, heparin (a drug that reduces blood clotting) and X-ray contrast media are fairly common examples of drugs that can cause these reactions.

Cwo toxic allergy

This mechanism takes place when antibodies develop against drug-protein coupling with certain cells, and the immune reaction results in cell damage. Such allergic blood disorders (thrombocytopenias, leukopenias and hemolytic anemias) are well known in general medicine.

Toxic-complex svndrome

This syndrome, also called Arthus reaction, is the result of the formation of antibodies that, on reaction with a drugprotein coupling, produce damage to blood vessels via complement, a constituent of blood serum.

When antisera were in common use in the treatment of certain infections, they often produced these reactions.
At present, penicillin is the commoThe sufferers develop pain in the joints, fever and blood disorders, and their skin becomes tender and urticaria often occurs. Delayed allergy Allergic contact eczema due to drugs applied directly to the skin is a common reaction. The same type of allergic reaction may be caused by taking the same drugs by mouth, injected into a vein, as a pessary, etc. Sulphonamides, chlorothiazide and numerous other drugs may produce this effect.

SIDE EFFECTS

The term side effects, or “adverse drug reactions” embodies a wide variety of toxic drug reactions that occur in numerous types of treatment. Assessing the incidence and consequences of side effects is extremely difficult, as causeand-effect relationships are often difficult or impossible to prove.

The ultimate proof, which may be unobtainable in cases of severe reactions, depends on disappearance of the effect on withdrawal of the suspected drug (although some severe reactions are irreversible) and reappearance on the administration of the drug.

It is also difficult to select a control population in a clinical setting to differentiate drug-related symptoms and signs from those that are non-drug-related; thus, there is a wide variation in the methods used to collect data on side effects of drugs.

Some studies of side effects rely on reactions reported voluntarily by doctors; others involve selected patient groups; information from patients may also be collected by direct questioning or by patients volunteering information.

There is also a potential for both under- and overestimating the incidence of side effects of drugs. Perhaps 2 to 3 percent of admissions to hospital are due to drug reactions (excluding deliberate overdose or drug abuse), and among patients already in hospital, the incidence of mild to severe side effects may be as high as 8 to 10 percent.

These data are difficult to interpret in terms of cause-and-effect, mortality and physical damage. The incidence of drug-related deaths is unknown, but probably only a few deaths in medical units are drug-related, and these are often in patients with serious diseases that warrant such risks.

The most commonly reported causes of drug-related deaths are:

- Gastro-intestinal hemorrhage and peptic ulceration, caused by corticosteroids, aspirin and other anti-inflammatory drugs.

- Other hemorrhages, caused by anticoagulants (which reduce blood clotting) or cytostatic agents (anti-cancer drugs).

- Aplastic anemia, caused by chloramphenicol, phenylbutazone, gold salts or cytostatic agents.
- Damage to the liver, caused by paracetamol, chlorpromazine or isoniazid.

- Failure of the function of the kidney, caused by analgesics (painkillers).

- Infections, caused by corticosteroids or cytostatic drugs.
- Anaphylaxis, caused by penicillin or its derivatives or by antisera. Although individuals vary considerably in their responsiveness to a particular drug effect, most toxic effects are related to the amount of drug taken. Previous contact with the drug is not necessary for the development of toxic reactions.

Side effects may be wanted under certain circumstances. For example, antihistamines given for hay fever may cause drowsiness as a side effect, but drowsiness may be a wanted effect when an antihistamine is given as a mild sleep remedy.

Drug interactions are defined as the alteration of the effects of one drug by the prior or concurrent administration of another and the usual result is an increase or decrease of the effects of one of the drugs.

Desired interactions are usually considered in the context of “combination therapy” (for example, in the treatment of raised blood pressure, asthma, certain infections and malignant tumors), in which two or more drugs are used to increase the therapeutic effects and/or reduce the toxicity of drugs. Unwanted interactions can cause side effects or the ineffectiveness of the drugs.

Relatively few of the known or suggested drug interactions have been sufficiently analyzed to determine their clinical significance. If an interaction appears likely, a doctor will consider prescribing alternatives.

Drug interactions include the concurrent administration of drugs having the same (or opposing) pharmacological actions as well as alteration of the sensitivity or the responsiveness of the tissues to one drug or another. Many of these interactions can be predicted from a knowledge of the effects of each drug, and by monitoring patients, doctors will be able to detect deviations from expected effects and dosages can be adjusted accordingly.

Interactions that occur because of the way a drug passes through the body are more complicated and difficult to predict because the interacting drugs have unrelated actions. The interactions are mainly due to the processes of absorption, distribution, metabolism and excretion; the type of response expected from the drug is not changed, only the magnitude and duration.

The following general points concerning drug interactions warrant emphasis. (1) The drugs for which interactions are most significant are those with potent effect and low safety margins, such as
- anticoagulant drugs (used to reduce clotting of the blood);
- digitalis preparations (used in the treatment of heart failure);
- cytotoxic medicines (used to treat cancer);
- drugs for the treatment of hypertension (high blood pressure);
- drugs for the treatment of low blood
sugar.

(2) It may be difficult to distinguish a drug interaction from symptoms of the illness or disease that can affect the body’s response to a drug.

(3) Not all patients develop reactions, even when it is known that interactions may occur. Individual factors, such as dose and metabolism, determine whether the phenomenon occurs.

(4) When the effects of drugs are being closely monitored, an interaction usually requires a change of dosage or drug and does not result in significant problems for the patient.
Avoidance ofdrur; interaction

To minimize the incidence and consequences of drug interactions, doctors should adhere to a number of general principles, and patients themselves should help doctors in detecting the symptoms of drug interaction.

(1) Doctors should know their patients’ total drug intakes, including all agents prescribed by others and those that are purchased without a prescription. Patients should honestly tell their doctors about all chemicals and other agents they are using.

(2) Doctors should prescribe as few drugs in as low doses as possible for as short a time as needed to achieve a desired effect, and should avoid unnecessary combinations.

(3) Doctors should know the effects, both wanted and unwanted, of all the drugs used (since the spectrum of drug interactions is usually contained within these effects) and know which doses produce which responses.

(4) Doctors should observe and monitor their patients for the drugs’ effects, particularly after any alteration in therapy.

(5) Doctors should, with the aid of accurate information from their patients, consider drug interactions as possible causes of any unanticipated trouble. If unexpected responses do occur, blood levels of drugs being taken should be measured, if possible. Most importantly, the doses of drugs should be altered until the desired effect is obtained. If this fails, the drugs should be changed to alternatives that will not interact with others being taken.

A medicine is any drug or other agent used to treat or prevent disease or to treat injury. The term medicine is generally used as a synonym for “drug.” In devising medicines for treating common conditions, an especially desirable factor is that the medicine should be capable of being taken by mouth that is, that it should be able to pass into the body unchanged in spite of being exposed to stomach acidity and the enzymes of the digestive system.
In many cases, this is possible but there are some important exceptions, such as insulin that has to be given by injection.
This method may also be necessary if vomiting or a disease of the stomach or intestine prevent normal absorption. In most cases, the level of the drug in the blood or tissues determines its effectiveness.

Factors that can make a difference in the effectiveness of a drug include:
- the route of administration
- the rate of distribution in the body
- the degree of binding the proteins of
the blood plasma
- the rate of breakdown
- the rate of excretion
- interactions with other drugs

In addition, there is an individual variation in drug responsiveness that is also apparent with undesired side-effects. These arise because drugs acting on one system commonly act on others.

Side effects

may be of various kinds, either non-specific, allergic or specific: - non-specific side effects include nausea, vomiting, diarrhea, malaise or skin reactions;
- allergic side effects include urticaria (nettle rash), skin reactions and anaphylaxis (hypersensitivity leading to shock);
- specific side effects are related to the action of the medicine on the organ to be treated such as abnormal heart rhythm as a side effect of digitalis. Mild side effects may be suppressed or simply accepted, but more serious ones must be watched for and the medicine stopped at the first sign of any adverse effect. Drugs may cross the placenta to reach the fetus during pregnancy, interfering with its development and perhaps causing deformity, as happened with thalidomide

A drug is a substance used as medicine in the treatment of disease, or a moodaltering substance, especially one that is addictive. Drugs are chemical agents that affect the systems of the body. In general they are taken to treat or prevent disease, but certain drugs, such as the opium narcotics, amphetamines, barbiturates and hallucinogens, are taken for their psychological effects and are drugs of addiction or abuse.
Many drugs are the same as or similar to chemicals occurring naturally in the body and are used either to replace the natural substance (for instance, thyroid hormone) when deficient, or to induce effects that occur when these is an abnormal concentration of the substance, such as with steroids or oral contraceptives.
Other agents are known to interfere with a specific mechanism or to antagonize a normal process. Many other drugs are obtained from other biological systems; fungi, bacteria (antibiotics), plants (e.g. digitalis) and several others are chemical modifications of natural products. In addition, there are a number of entirely synthetic drugs (e.g. barbiturates), some of which are based on active parts of naturally occurring drugs.