Macrolides are a class of antibiotics that are often used to treat infections in people who are allergic to penicillins.
Macrolides include the following:
Azithromycin
Clarithromycin
Erythromycin
Fidaxomicin
Macrolides work by preventing bacteria from producing proteins they need to grow and multiply.
Fidaxomicin is given only by mouth (orally) and is minimally absorbed into the bloodstream when taken orally. It is used to treat Clostridioides difficile–induced colitis but does not do much harm to the other bacteria that normally live in healthy intestines.
Macrolides interact with many other medications (called a drug-drug interaction). Often, the interaction increases the effects, including the side effects, of the other medications. When given with certain other medications, macrolides can increase the risk of sudden cardiac death in people who have long QT syndrome.
Macrolides
Medication | Common Uses | Some Potential Side Effects |
|---|---|---|
Azithromycin Clarithromycin Erythromycin Fidaxomicin | Respiratory infections For azithromycin: Chlamydial infections of the reproductive organs and urinary tract For fidaxomicin: Used only for Clostridioides difficile | Abdominal pain, nausea, vomiting, and diarrhea (especially at higher doses) Abnormal heart rhythms (arrhythmias)* |
* These side effects are not reported with fidaxomicin. | ||
(See also Overview of Antibiotics.)
Use of Macrolides During Pregnancy and Breastfeeding
Macrolides should be taken during pregnancy only when the benefits of treatment outweigh the risks.
With erythromycin and azithromycin, no harmful effects on the fetus have been observed in animal studies, but no well-designed studies have been done in pregnant women. Erythromycin is considered among the safest antibiotics to use during pregnancy. It is considered safer than azithromycin because it has been used more, and thus more is known about it.
With the macrolide clarithromycin, harmful effects on the fetus have been observed in animal studies. Therefore, pregnant women should not take clarithromycin except when there is no alternative medication.
Use of erythromycin during breastfeeding is generally considered acceptable. Whether other macrolides are safe to use during breastfeeding is unknown.
Drug Information for the Topic
