What Are the Side Effects of Taking Antibiotics Long-Term?

Last Editorial Review: 1/11/2018

Ask the experts

What are the complications and/or effects of taking antibiotics for a life-long disease such as rosacea? Do the antibiotics become ineffective and/or do you develop immunity to them?

Doctor's response

This is an important question that raises several issues. First of all, it should be noted that any potentially effective drug has possible side effects. In fact, no medication, whether it is by prescription or available over the counter, should be utilized without some consideration of the potential for toxic effects. Antibiotics, even used for short periods of time, let alone for life-long therapy, raise the issues of both toxicity and the emergence of bacterial antibiotic resistance. (Bacterial antibiotic resistance means that the bacteria do not respond to the antibiotic treatment.)

It is also important to note that antibiotics are frequently used in settings where they will not provide any benefits. An example of this sort of inappropriate use of antibiotics is for viral infections, such as the common cold. In fact, there is a tendency for patients to believe that if they are ill with an "infection", an antibiotic is the solution. Well, it's not always.

In reality, inappropriately used antibiotics will do nothing except place the patient at an unnecessary risk for potential side effects. In addition, too much use of an antibiotic can cause bacteria to become increasingly antibiotic resistant. Consequently, the resistant bacteria will not respond to the antibiotic in the future when this therapy may truly be needed. Thus, antibiotics should be used sparingly and with caution in all situations. If a physician tells a person that an antibiotic is unlikely to be helpful, it is in that person's best interest to not take the antibiotic.

With that said, there are clearly situations where antibiotics are necessary to treat bacterial infections, such as of the lung (pneumonia), skin, or urinary tract. In these settings, treatment should be initiated at the recommendation of a physician and taken for a fixed duration of time (rarely more than 7-10 days). If antibiotics are used with care, most individuals will not develop resistant bacteria and therapy should be highly effective.

Furthermore, there are select situations, including certain severe infections, where therapy must be given for prolonged periods of time. In these cases, it is clear that the risk of not treating the infection outweighs the potential for developing side effects and bacterial resistance. In very few situations, however, is antibiotic therapy used for months or years.

In the case of rosacea, most cases can be managed with topical (applied to the skin) antibiotics, such as topical metronidazole. (The pill form is much less commonly needed.) Similarly, a severe form of acne (acne vulgaris) occasionally requires oral tetracycline therapy, but most often can be controlled with topical antibiotics such as metronidazole, clindamycin, or erythromycin.

Whenever possible, topical therapies are preferred to pills, as they are less likely to result in side effects or antibiotic resistance. Sometimes, however, a condition is unresponsive (refractory) to topical treatment and responds to the pill form of an antibiotic. In such a situation, the patient must decide, along with her or his physician, whether the risks of ongoing therapy are outweighed by the severity of the condition.

Medical Author: Eric S. Daar, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.