Sometimes it seems like there are more medicines than there are diseases, and it
can be hard to keep them straight. Some can be bought over the counter at pharmacies
or other stores. Others require a doctor's prescription. Some are available only in
What Are Medicines?
Medicines are chemicals or compounds used to cure, halt, or prevent disease; ease
symptoms; or help in the diagnosis of illnesses. Advances in medicines have enabled
doctors to cure many diseases and save lives.
These days, medicines come from a variety of sources. Many were developed from
substances found in nature, and even today many are extracted from plants.
Some medicines are made in labs by mixing together a number of chemicals. Others,
like penicillin, are byproducts of organisms such as fungus. And a few are even biologically
engineered by inserting genes into bacteria that make them produce the desired substance.
When we think about taking medicines, we often think of pills. But medicines can
be delivered in many ways, such as:
liquids that are swallowed
drops that are put into ears or eyes
creams, gels, or ointments that are rubbed onto the skin
inhalers (like nasal sprays or asthma inhalers)
patches that are stuck to skin (called transdermal patches)
tablets that are placed under the tongue (called sublingual medicines; the medicine
is absorbed into blood vessels and enters the bloodstream)
injections (shots) or intravenous (inserted into a vein) medicines
No medicine can be sold unless it has first been approved by the U.S. Food and
Drug Administration (FDA). The makers of the medicine do tests on all new medicines
and send the results to the FDA.
The FDA allows new medicines to be used only if they work and if they are safe
enough. When a medicine's benefits outweigh its known risks, the FDA usually approves
the sale of the drug. The FDA can withdraw a medicine from the market at any time
if it later is found to cause harmful side effects.
Different Types of Medicines
Medicines act in a variety of ways. Some can cure an illness by killing or halting
the spread of invading germs, such as bacteria and viruses. Others are used to treat
cancer by killing cells as they divide or preventing them from multiplying. Some drugs
replace missing substances or correct low levels of natural body chemicals such as
some hormones or vitamins. Medicines can even affect parts of the nervous system that
control a body process.
Nearly everyone has taken an antibiotic. This type of medicine fights bacterial
infections. Your doctor may prescribe an antibiotic for things like strep
throat or an ear infection. Antibiotics work either by killing bacteria or halting
their multiplication so that the body's immune system can fight off the infection.
Sometimes a part of the body can't make enough of a chemical. That can also make
you sick. Someone with insulin-dependent diabetes, for instance, has a pancreas that
can't produce enough
(a hormone that regulates glucose in the body). Some people have a low
production of thyroid hormone, which helps control how the body uses energy. In each
case, doctors can prescribe medicines to replace the missing hormone.
Some medicines treat symptoms but can't cure the illness that causes the symptoms.
(A symptom is anything you feel while you're sick, such as a cough or nausea.) So
taking a lozenge may soothe a sore throat, but it won't kill that nasty strep bacteria.
Some medicines relieve pain. If you pull a muscle, your doctor might tell you to
take ibuprofen or acetaminophen. These pain
relievers, or analgesics, don't get rid of the source of the pain — your
muscle will still be pulled. What they do is block the pathways that transmit pain
signals from the injured or irritated body part to the brain (in other words, they
affect the way the brain reads the pain signal) so that you don't hurt as much while
your body recovers.
As people get older, they sometimes develop chronic or long-term conditions. Medicines
can help control things like high
blood pressure (hypertension) or high cholesterol. These drugs don't cure the
underlying problem, but they can help prevent some of its body-damaging effects over
Among the most important medicines are immunizations
(or vaccines). These keep people from getting sick in the first place by immunizing,
or protecting, the body against some infectious diseases. Vaccines usually contain
a small amount of an agent that resembles a specific germ or germs that have been
modified or killed. When someone is vaccinated, it primes the body's immune system
to "remember" the germ so it will be able to fight off infection by that
germ in the future.
Most immunizations that prevent you from catching diseases like measles, whooping
cough, and chickenpox are given by injection. No one thinks shots
are fun. But the diseases they prevent can be very serious and cause symptoms that
last much longer than the temporary discomfort of the shot. To make life easier,
now you can get immunizations at many pharmacies.
Although some medicines require a
prescription, some are available in stores. You can buy many medicines for pain,
fever, cough, or allergies without a prescription. But just because a medicine is
available over-the-counter (OTC), that doesn't mean it's free of side effects. Take
OTC medicines with the same caution as those prescribed by a doctor.
No matter what type of medicine your doctor prescribes, it's always important to
be safe and follow some basic rules:
If you feel worse after taking a medicine, tell your doctor right away.
Double-check that you have the right medicine. If you get the same
prescription filled more than once, check that it's the same shape, size, and
color as the last time. If not, be sure to ask the pharmacist about it.
Read the label and follow directions. Ask if you have questions.
Take medicines exactly as prescribed. If the instructions say take one tablet
four times a day, don't take two tablets twice a day. It's not the same.
Ask if the medicine is likely to affect everyday tasks such as driving or concentrating
Don't take more medicine than is recommended. It won't make you heal faster or
feel better quicker. In fact, an overdose of medicine can make you sick.
Always follow your doctor's or pharmacist's instructions. For instance, he or
she may tell you to take a medicine with food to help lessen the stomach upset it
can cause or instead to take the medicine on an empty stomach so as not to interfere
with the medicine's absorption into your body.
Never share prescription medicine with anyone else, even if that person has the
same thing as you do. Today's medicines are very complex, and the dosages tend to
be precisely prescribed for each person's needs. Either under-dosing or overdosing
can be harmful. Additionally, someone else's body may react differently to the same
medicine (for example, if the person has an allergy to one of the components of the
If you're already taking a medicine but also want to take something you can buy
over-the-counter, ask the pharmacist. There could be a bad interaction between the
Always tell your doctor and pharmacist if you're taking any other medicines or
any herbal supplements so that he or she can check for any interactions between the
Be sure to tell your doctor if you are pregnant or might be pregnant. Some medicines
can be harmful to the baby. Also, let your doctor or pharmacist know if you are
breastfeeding, as some medications can cause problems with nursing.
Remember that drinking alcohol can dramatically worsen the side effects of many
Even if you get sick with what you think is the same old thing, don't decide on
your own that you know what's wrong and take some leftover medicine. Taking that medicine
for a different disease might not work — and it can even be harmful. Talk to your
Take antibiotics for the full length of the time prescribed, even if you start
to be feel better, so that all the germs are killed and the infection doesn't bounce
Keep medicines in their original labeled containers, if possible.
Medicines should not be stored in your bathroom because heat and humidity can
affect the potency of the drug. Most medicines should be kept at room temperature
and away from sunlight. Some must be refrigerated. Check with your pharmacist or doctor
if you aren't sure.
Make sure all medicines are stored safely and out of the reach of younger brothers
or sisters and pets.
If you have any allergies, tell your doctor and pharmacist before they start you
on a new medicine.
If you get a rash, start itching, vomiting, or have trouble breathing after starting
a medicine, tell your parents immediately. Breathing difficulty, breaking out in hives,
or suddenly developing swelling of the tongue, lips, face, or other body parts may
be signs of a severe allergic reaction — get emergency medical care right away.
Taking medicines may feel like a hassle sometimes. But medicines are the most effective
treatments available for many illnesses. If you ever have any questions about what
a medicine does or how you should take it, talk with your doctor or a pharmacist.