新编大学英语第三册unit8 Text C: A Pill for Every Ill?
UNIT 8 AFTER-CLASS READING 2; New College English (III)
A Pill for Every Ill?
1 "A desire to take medicines," wrote the Canadian physician Sir William Osler in 1891, "is, perhaps, the great feature which distinguishes man from other animals." If Osler's observation was true in his time, it is even more strikingly true today. People take medicines, and take them, and take them in staggering amounts.
2 By the 1980s, Americans were consuming yearly more than six billion dollars' worth of nonprescription cough and cold remedies, painkillers, vitamins and a host of other products. On any given day about 40 million Americans almost one fifth of the population used one nonprescription remedy or another. In addition, two thirds of the population had used prescription drugs at some time, and about 75 million had taken them regularly. These drugs, available only by prescription and dispensed by a licensed pharmacist, are too potent and too hazardous to use without precise instructions from a doctor yet they, too, are obviously taken in awe-inspiring quantities.
3 Yet even the most miraculous miracle drug harbors within it powerful dangers. Most medicines, whether synthesized in a test tube or extracted from natural substances, are chemicals that are foreign to the body and can be poisonous to one degree or another. Even those that are compounds normally present in the body, such as insulin, can cause harm. There simply is no such thing as a perfectly safe drug. Even familiar, seemingly unthreatening medicines such as aspirin can have multiple effects that range from mild discomfort to lethal shock.
4 Before taking a drug, one should weigh its potential risks against its benefits. Aspirin, for example, usually presents only modest risks, and the benefits often sought from it, such as relief from a headache, seem similarly modest. When the risk increases, as it does if the presence of stomach ulcers brings hazard of internal bleeding from the irritation of aspirin's acid, the serious risk may outweigh the benefit; it may be wiser to endure the headache or use another agent. A cancer patient, on the other hand, may be justified in trying extremely toxic medicines because they hold the only remaining promise of arresting the disease and prolonging his life.
5 Circumstances may weigh against the use of otherwise acceptable drugs: A farmer, for example, should pause before using an antibiotic that may also cause sensitivity to sunlight. Women, who are normally free to take any drug a man can take, should be extremely cautious of any drug when they are pregnant, because many medicines can affect unborn babies and some affect them disastrously.
6 The point of the following cartoon is comic, but it has serious implications: Knowing how medicines find their targets and do their jobs is important to everyone who uses them. Equally important indeed, sometimes far more important is knowing how and why they can miss their targets, with unintended and undesirable side effects. Consider these case histories, in which the facts are true though the names of the participants are omitted.
(There is a picture of a mother and her baby. The following is the text attached to it.)
"One pill is for your sore throat; the other is for your earache."
"How do the pills know where to go?"
7 As the surgeons at a Virginia hospital started to operate on a 42-year-old woman, every sign indicated a simple procedure. Then after the first incision, the patient began to bleed a lot and a routine operation suddenly became a life-threatening emergency. The physicians quickly gave their patient an injection of vitamin K which promotes blood clotting. Though the surgeons trying to control the bleeding did not know it, the patient had been taking large amounts of a popular painkiller for over a year; though she did not know it, the over-the-counter medicine contained aspirin, which not only kills pain but also slows blood clotting.
8 An attorney had just returned from a visit to the dentist in an office near his own. A painful gum infection had been drained, and he had in his pocket a bottle of penicillin pills, prescribed by the dentist. He took the first pill. Within minutes, his hands and feet began to itch, his face swelled and he was overcome by a fit of choking and gasping. He rushed back to the dentist. There he received treatment to counter an overwhelming allergic reaction to the antibiotic a reaction that, if left untreated, could have caused a fatal collapse within minutes.
9 A 61-year-old diabetic woman had a headache. She took two plain aspirin tablets along with her evening dose of tolbutamide, a medicine that controls diabetes by reducing sugar in the blood. Then she lay down to rest before dinner. When her daughter came home from work, she found her mother unconscious. A doctor, summoned at once, gave the unconscious woman an injection of glucose, which brought her back to consciousness. Her headache had been an early sign of dangerously low blood sugar. The combined action of tolbutamide and aspirin had reduced her blood sugar to a point at which she lapsed into a diabetic coma.
10 The very drugs that caused these terrifying effects are rightly considered modern medical wonders, but like other prescription and nonprescription medicines they can sometimes bring at least three kinds of consequences very different from those intended. For one thing, they trigger side effects, extra actions in addition to their intended ones. One of the known side effects of aspirin is a reduction in blood clotting. Side effects like this one can be predicted. The woman who nearly lost her life in a routine operation because of the side effect of aspirin is a case in point. If she had told her doctors about her medication habits, they would have told her to stop taking the drug and would have delayed the surgery until her blood could clot normally.
11 A second type of drug reaction, typified by the lawyer's near-catastrophic allergy to penicillin, is of its nature unexpected. Doctors know that some people are allergic to penicillin, but they cannot easily tell in advance who has the allergy. The adverse reaction largely depends on a victim's distinctive body chemistry, and the tools that measure body chemistry are not sufficiently sophisticated to provide an accurate prediction.
12 A third type of reaction arises from the interference of other substances with a drug. When several drugs are taken together, potential hazards are compounded. The human body consists of a great many chemicals, which sometimes attract one another, sometimes repel, always modifying one another's characteristics and actions. When a drug a foreign chemical drops into this mixture, the result can be profound and disturbing. The chemicals in food, beverages, alcohol and drugs may lessen or cancel the effect of a medicine. Or a drug's effects may be enhanced by another potent substance. This is what happened when the elderly diabetic took aspirin and tolbutamide together; the effect was more potent than the sum of two drugs taken separately.
