If I have a sinus infection, how safe is it to take antibiotics while nursing? Are some antibiotics safer than others? What about Z-pack?

A.

For such a short question, there is quite a lot to consider. First, let me discuss sinusitis, which is, as the name suggests, an infection of the sinuses. The classic symptoms are fever, nasal stuffiness, facial pain and nasal discharge. There may also be a cough and foul breath. All of these symptoms are rarely present in the same person. Even if you have many of the symptoms, you may not need treatment with antibiotics. Antibiotics are required only for sinus infections caused by bacteria. However, viruses -- which are not killed by antibiotics -- cause many of the same symptoms. To definitively prove that a patient has a bacterial sinus infection, a physician needs to place a needle in the sinus and draw out fluid for culture (incubation to grow any bacteria present). This procedure is obviously not commonly done in general practice, though occasionally it is performed in very difficult cases. Since practitioners generally have little way of knowing which patients with sinus symptoms will benefit from antibiotics and which will not, we end up treating most of the cases.

Now, assuming you need antibiotics for your sinus infection, what about breastfeeding? As you no doubt know, certain drugs are safe in adults but can adversely affect the fetus and the nursing infant. Some drugs are dangerous in pregnancy, but they can be taken safely while breastfeeding. Some drugs may actually be safe but have not been studied very well in lactating mothers and so they should usually be avoided. The safest approach is to remind your doctor that you are breastfeeding and ask specifically whether any drug you plan to take will be safe for your child.

To treat sinusitis during lactation, there are not very many choices. Amoxicillin (trade name Amoxil) is considered safe, but it is not the most effective drug. Trimethoprim-sulfamethoxazole (Bactrim or Septra) can cause jaundice in the infant and should not be given. To my knowledge, there are inadequate studies to state one way or the other whether Z-pack (generic name azithromycin) is safe when breastfeeding, so I would not use it. Clarithromycin (Biaxin) carries no precautions for lactating mothers, but I am not sure that it has been adequately studied, either.

Discuss your concerns with your doctor. One option is to stop nursing and bottle-feed the baby until the course of antibiotics is completed. This can be a useful approach when the infection is serious and the only good choice is an antibiotic that could harm the nursing infant.