THE EFFECTS OF DRUGS
Before a physician select a drug to be used in the treatment of a sick person, he or she carefully weights the benefits and the risk. Obviously, the doctor expect a positive result from the drug, a cure of the condition or at least the relief symptoms, at the same time, consideration has to be given to the risk, for all drugs are potentially harmful, some of them considerably more so than others.
Some drugs can produce rapid and spectacular relief from the symptom of disease. Nitroglycerin frequently provide almost immediate relief for the pain or angina; other drugs can quickly alleviate the symptoms of an asthmatic attack. Conversely, some drugs take much longer to produce a response. It may, for example, require several weeks of treatment with antidepressant drug before a person experience maximum benefit. this can be worrisome unless the physician has warned of the possibility of the delay in the onset of beneficial effects.
The side effect of the drug are the known and frequently experienced, expected reaction to a drug. The old concept of the drug as a “magic bullet” that could be targeted to a specific type of cells is now recognized as inaccurate, whether a drug is taken by mouth, by injection or by inhalation, it will be distributed throughout the body and its effects are unlikely to be restricted to one particular type of tissue or organ.
for example, antocholingergic drugs, which are prescribed to relieve spasm in the wall of the intestine, may also affect the eyes, causing blurred vision; the mouth, causing the retention of urine. such side effects may gradually disappear as the body becomes used to the drug, but if side effects persist, the dose of the drug may have to be reduced, or the time between doses may have to be increase. The side effects of certain drugs especially some anticancer drugs, can often the quite serious, such drugs are administered because they many be the only agents available to the treatment of a disease that might otherwise prove fatal. however, all drugs, even the mildest,, should be regarded as chemicals with a potential for producing serious , toxic reaction, especially if they are misused or abused.
Adverse reaction are unsuspected, unpredictable reaction that are not related to the usual effects of normal dose of drug. Unpredictable drugs reaction may be caused by conditions in the patient such as an allergy or a genetic disorder, like the absence of an enzyme that usually inactivate the drugs. common adverse reaction of this types include a rash, swelling of the face or jaundice, they may also be due to interaction with other drugs . Unpredictable drugs reaction usually necessitate withdrawal of the drugs under medical supervision.
Beneficial Vs. Adverse effects
In evaluating the risk/benefit ratio of a drug which he or she may prescribe, a physician weights the therapeutic benefits to the sick person against the possible adverse effects. for example,such side effects as nausea, headache, and diarrhea may result from taking antibiotic. but they will certainly be considered acceptable risk of the problem is a life threatening infection requiring immediate treatment. on the other hand, such side effects wound be considered unacceptable for an oral contraceptive that is taken over a number of years by a healthy patient. because some people are more at risk from adverse drug reaction than others (particularly those with a history of drug allergy), the physician normally check whether there is any reason why a particular drugs should not be given.
The word Placebo- Latin form ” I will Please”– is used to describe any chemically inert substance given as a substituted for a drug. Any benefit gained from taking placebo occurs because the person taking it believes that it will produce good result.
New drugs are almost always tested against a placebo preparation in clinical trials is a way to assess the efficacy of a drug before it is marketed. the placebo is made to look identical to the active preparation, and volunteers are not told whether they have been given the active drug or the placebo. sometimes the physicians is also unaware of which preparation an individual has been given. this is also known as a Double blind Trial. In this way, the purely placebo effect can be eliminated and the effectiveness of the drug determined more realistically.
Sometimes the mere taking of medicine has a psychological effect and produces a beneficial physical response. this type of placebo can make an important contribution to the over all effectiveness of chemically active drug, and is most commonly seen with analgesics, antidespprasant and anti-anxiety drugs. some people known as a placebo responders, are more likely to experience this sort of reaction than the rest of this population.