|Every day in the US, medication costing millions of dollars is prescribe to hundreds of thousands people. There are thousands of different drugs used to treat hundreds of illnesses. What follows is a general guide to some of the broad categories of medication, how they work and common side effects.
Acetaminophen and aspirin are the mildest analgesics, used for headaches, joint pains, menstrual pain, and toothache. They are equally effective, but aspirin also reduces inflammation. Acetaminophen can be used in children under the age of twelve. Side effects are rare, but it is potentially fatal even in minor overdose because of toxic effects on the liver. Side effects of aspirin and other anti-inflammatories (e.g. ibuprofen) include stomach irritation and bleeding. Asthma sufferers can be sensitive to aspirin, leading to increased wheezing, and even death in some cases. Stronger analgesics work on the brain to reduce the perception of pain. These include drowsiness, constipation, nausea and vomiting.
THE EFFECT OF ANALGESICS
Strong analgesics known as opioids, derived from opium, are used to relieve sever pain. Pain is transmitted in signals along nerves from the source of pain to the brain, where it passes from one brain cell to another until it reaches the part of the brain that interprets the signal as pain. Opioid analgesics block the transmission of the nerve impulses in the brain, reducing the sensation of pain.
There are around ten different classes of drugs used to treat variety of conditions, including high blood pressure, blood clots, angina, and palpitations. The best known of the drugs are water tablets (diuretics). They remove excess fluid from the circulatory system, lowering blood pressure and improving breathing in heart failure. Side effects include stomach upsets, gout, and rashes.
Beta-blockers reduce heart rate and lower blood pressure, but can cause tiredness, cold hands and feet, and sleep disturbances. They should not be taken by asthmatics because they may trigger a fatal attack of wheezing. Digoxin is used to treat irregular heart rate and may induce nausea, vomiting, and loss of appetite if the dosage is too high. Some drugs used for treating raised blood pressure can cause impotence (reversible on stopping medication).
There are two types of asthma therapy. Treatment of wheezing attacks is by inhaled drugs, including salbutamol and terbutaline (known as relievers), which open up the airways by relaxing the muscle in the walls of breathing tubes. Preventatives, such as inhaled steroids, improve breathing by reducing the amount of sticky mucus blocking the airways. Inhaled drugs have few side effects, although steroids can cause an overgrowth of yeast infection at the back of the throat.
HOW ANTACIDS WORK
Acid in digestive juices may inflame the lining of the stomach and irritate the stomach walls. Antacids are used to relieve indigestion or help stomach ulcers to heal. They are mild alkaline substances taken orally that neutralizes acidity in the digestive juices, allowing eroded areas in the mucus membrane lining the stomach to recover.
Digestive juices in the stomach contain acid, which may eat away at the mucus layer and inflame the stomach lining.
The antacid combines with stomach acid and neutralizes it, reducing irritation and giving the mucus membrane time to heal.
All drugs for depression work by affecting neurotransmitters, chemicals in the brain that pass signals between nerves. These neurotransmitters are low in depressed individuals. Older drugs called tricyclics work mainly on noradrenalin. Side effects include drowsiness, agitation, dry mouth, constipation, blurred vision, and retention urine.
Newer drugs, such as Prozac, raise the levels of serotonin to improve symptoms. They may cause nausea, agitation, loss of appetite, and sweating. Antidepressants take two to four weeks to have an effect, and should always be withdrawn slowly.
Many stomach problems, including ulcers, heartburn, and indigestion, are caused by excess acid in the stomach. The simplest drugs used to treat symptoms are antacids, which neutralize stomach acid. These drugs can form a raft on top of the stomach contents, preventing backflow from the stomach into the esophagus.
HOW BRONCHODILATORS WORK
More advanced drugs reduce acid production by blocking the action of nerves supplying acid-producing glands in the lining of the stomach (H2 blockers), or by acting on the acid pump within the cells of these glands (proton pump inhibitors). These drugs have few side effects, and work so well that it is difficult to persuade patients to stop taking them.
Bronchodilators widen the airways of the lungs to ease breathing difficulties caused by conditions such as asthma. Before inhaling the drug, the airways become abnormally narrowed as the muscles in their walls contract.
Bronchodilators relieve wheezing, tight chest, and shortness of breath by acting on nerve endings in the muscles in the walls of the airways. The muscles relax and the airways widen, increasing airflow in the lungs.