To have a cold? Do you take an antibiotic?

Ear bread? Take an antibiotic.

Acne? Take an antibiotic.

That is what people think anyway. But is this really the best course of action? Does the short-term gain outweigh the long-term consequences? And for starters, are there any short-term gains? Antibiotics do not help colds caused by a virus. Most ear infections clear up just as quickly without antibiotics. It’s true that severe acne gets better with oral antibiotics, but what about the millions of teens who take them for just a few pimples?

Every day, doctors see problems related to the use of antibiotics. Here are five reasons why doctors try to limit its use and why you should think twice before taking one.

1. Yeast infection. Often times, patients do not realize that our bodies are covered in germs, both inside and out. The skin, the mouth, the vagina, the intestine all have their own population of bacteria. For the most part, these microbes stay where they belong and do what they are supposed to do. One function of the normal flora (normal population of bacteria) is to keep the bad ones at bay. There are always some harmful bacteria around, but they are usually displaced by the good ones. However, taking an antibiotic often kills the good bacteria population and allows a different microbe to take over. Most commonly, yeast is the intruder. Once the bacteria are gone, the few yeasts that remain on the skin, vagina, or colon claim the territory as their own. Yeast overgrowth often leads to symptoms of vaginal yeast infection or a yeast infection of the skin, usually in warm areas such as the armpits, groin, or under the chest.

two. Clostridium difficile colitis. Just as yeast overgrowth and infection can occur when normal bacteria are killed, so can harmful bacteria. Often times, the normal flora of the gut is susceptible to an antibiotic that is taken to treat disease. However, Clostridium difficile (gold vs. Dif.) common antibiotics like penicillin, sulfonamides, or erythromycin do not kill it. The few vs. Dif. the bacteria that you can harbor in your intestine will not harm it as long as their numbers are limited. But when overgrowth occurs, foul-smelling diarrhea occurs, sometimes accompanied by fever, dehydration, or the need for hospitalization. C. diff. Colitis requires a different antibiotic to rid your body of this harmful organism.

3. Resistance. As mentioned above, certain bacteria are already resistant to antibiotics. However, there is the possibility that many bacteria will become resistant to useful antibiotics. What if penicillin becomes ineffective for strep throat? In some cases it already is. MRSA (methicillin-resistant staph) is a harmful bacteria that has emerged in recent years due to overuse of antibiotics. If you remember your genetics from high school, you may know that when bacteria (or people) multiply by the billions, some mutations are unavoidable. In the microbe population, this often means that when billions of bacteria reproduce, some of the daughter bacteria inherit a mutation that makes them resistant to certain antibiotics. In general, these mutated bacteria, although stronger in the sense that they could survive a penicillin “attack,” are actually weaker in other respects and die naturally but prematurely. However, if the entire population of bacteria is subjected to a round of antibiotics, the weaker but penicillin-resistant bacteria can live to repopulate the environment. So the next time penicillin is used, it won’t work. Doctors see antibiotic resistance every day. It IS a real threat, and at least for now, we have no new antibiotics on the horizon to use against these resistant bacteria.

4. Nausea, vomiting and diarrhea. Even apart from killing the normal flora of the body, antibiotics can cause nausea, vomiting, or diarrhea on their own. After all, these are chemicals, chemicals that the body can reject as foreign. The erythromycin class of antibiotics is especially known to cause gastrointestinal symptoms by stimulating natural bowel contractions.

5. Drug allergy. Any patient can be allergic to any medication and antibiotics are no exception. Although an allergy to antibiotics can often manifest itself only as a rash, true anaphylaxis can occur with the use of any antibiotic. Anaphylaxis is a total body allergic response that can include hives, nausea, dizziness, itching, swelling, and shortness of breath, very similar to a bee sting allergy. Whenever you think you are having a reaction to a medicine, call your doctor. If you have trouble breathing or feel like you are going to faint, call 911. This is a medical emergency.

Just writing this reminds me to be careful when prescribing antibiotics to my patients. The next time your doctor prescribes a round of penicillin or another antibiotic, ask how necessary the medication really is. They are often prescribed for convenience rather than necessity. If an antibiotic will only cure you a day faster, you might be better off doing without it.

Copyright 2011 Cynthia J. Koelker, MD