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Antibiotics Primer

Virtually every parent has had experience with the pink liquid dosed out to infants and children to treat common childhood "bugs." What are these wonder antibiotics? Why do certain prescriptions seem to work better than others for your child? Can children develop immunities to antibiotics? Pediatrician J. Jordan Storlazzi, MD, of the duPont Hospital for Children staff, and Stuart Levine, Director of duPont's pharmacy answer these and other questions about antibiotic medications.

What Are Antibiotics?
Antibiotics are agents used to kill or stop the growth of bacterial infections in the body. The physician can usually tell by examining the child if the infection is bacterial or viral. Most of the infections seen in doctors' offices are viral. Antibiotics are not helpful in treating a viral infection - it must simply run its course, with treatment depending on the symptoms.

Types of Bacterial Illnesses Treated With Antibiotics
The most common bacterial infections of early childhood, including otitis media (ear infection), sinusitis, pneumonia and kidney infection respond well to antibiotics.

Physicians in this region seem to prescribe amoxicillin frequently. Why is that?
Amoxicillin is prescribed often in the Wilmington, Delaware area because it is effective about 90 percent of the time in treating common childhood infections. This may not be the case in other areas of the U.S. Depending on where you live, the "bugs" that are going around are resistant to certain medications. Amoxicillin also happens to be the least expensive antibiotic and the one that causes the fewest side effects.

What about the 10 percent for whom amoxicillin doesn't work?
Then a different medication is prescribed - products such as Ceclor, Augmentin, Bactrim or Pediazole. They are not necessarily stronger or better than amoxicillin, they may just work well under the circumstances. If it appears a child is not responding to drug "A," we assume the "bug" he has is resistant to the drug, so we try drug "B." Ceclor and Augmentin, for example, are more expensive than amoxicillin and have more side effects associated with them, including diarrhea and skin rashes. But when the first line of treatment is not successful, we go on to the second line.

If a child experiences stomach pain, vomiting or skin rashes after taking an antibiotic, does it mean she is allergic to the medication?
Not necessarily. Gastrointestinal distress associated with antibiotics is not uncommon. Although the physician will usually discontinue a drug if it seems to be causing problems, the child may be able to take another drug in the same antibiotic family. Skin rashes need to be evaluated by the physician, but the same thing holds true. Another drug in the penicillin family, for example, may produce no side effects whatsoever.

Do children become immune to certain medications?
No, it is a matter of resistance rather than immunity. Children's infections may be resistant to certain medications. For example, we may have treated a child successfully with amoxicillin on three separate occasions for three different infections. Then, on the fourth attempt, it doesn't work. This is not because the child has built up an immunity to the medication. Rather, it is due to this particular infection being resistant to the amoxicillin. Then we try another antibiotic. Every infection is different, so we can't assume that what worked once will always work. Chances are that your child will need to be treated with more than one type of antibiotic during his or her early years.

Why is it necessary to take antibiotic medication for 10 days when it seems to have worked after just a day or two?
You want to be sure the bacteria's growth has been stopped. A child may get relief from a painful ear infection after only a few doses of the antibiotic. The initial doses "zap" the infection but don't eradicate it. The bacteria are reduced so much within the first day or two that the child feels better very quickly. However, the 10-14 day course of treatment is recommended because the bacteria have the propensity to replicate if they are not all destroyed. Finishing the prescription will help to ensure that all remnants of the infection are gone.

Why don't doctors seem to prescribe penicillin any longer?
Penicillin is useful in treating a much narrower spectrum of illnesses than in decades past. Today, only about 25 percent of bacterial infections respond to treatment with penicillin, so we prescribe it infrequently. Penicillin seems to be effective in treating strep infections. This is why we are constantly developing new drugs - because the new illnesses that are out there are becoming more and more resistant to existing medicines.

What's the Difference Between Sulfa Drugs, Penicillins, and Tetracyclines?
They are different classes of antibiotics produced in different ways. For example, some are cultured, others are grown naturally and then modified in some way. Still others are produced synthetically. The penicillin family of drugs is bactericidal, meaning they kill the bug that caused the infection. Others such as erythromycin and tetracycline stop the bacteria from multiplying, then the body's natural defenses kill it off.Some classes of antibiotics also have side effects associated with them. We don't prescribe tetracycline much for children because of its discoloring effect on teeth. Sulfa drugs (like Bactrim) make people very sensitive to sunlight. Parents should be especially cautious about exposing children who are taking sulfa medications to excessive sunlight. Exposure could result in a severe sunburn with minimal time in the sun.

Can Antibiotics Save My Child's Life?
Yes, antibiotics really are miracle drugs. Since the discovery of penicillin in the 1940s, millions of lives have been saved. Illnesses like strep infections and pneumonia, which used to be common causes of mortality, now rarely result in death, thanks to antibiotics.As pediatric health-care providers, our emphasis is on preventive health care. While penicillin and its descendants have saved millions, immunizations have saved many millions more. Smallpox has been completely eliminated; diseases like measles and whooping cough are being eradicated. Parents concerned with maintaining their children's health will not only want to seek prompt treatment for infections, but also to make sure their children get regular check ups and all their recommended immunizations.

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