Macrolides are a class of antibiotics Overview of Antibiotics Antibiotics are drugs used to treat bacterial infections. They are not effective against viral infections and most other infections. Antibiotics either kill bacteria or stop them from reproducing... read more that are often used to treat infections in people who are allergic to penicillins.
Macrolides include the following:
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 Drug Absorption Drug absorption is the movement of a drug into the bloodstream after administration. (See also Introduction to Administration and Kinetics of Drugs.) Absorption affects bioavailability—how quickly... read more into the bloodstream when taken orally. It is used to treat Clostridioides difficile– induced colitis Clostridioides (formerly Clostridium) difficile-Induced Colitis Clostridioides difficile (C. difficile)–induced colitis is an inflammation of the large intestine (colon) that results in diarrhea. The inflammation is caused by toxin produced... read more but does not do much harm to the other bacteria that normally live in healthy intestines.
Macrolides interact with many other drugs (called a drug-drug interaction Drug-Drug Interactions The effect a drug has on a person may be different than expected because that drug interacts with Another drug the person is taking (drug-drug interaction) Food, beverages, or supplements the... read more ). Often, the interaction increases the effects, including the side effects, of the other drugs. When given with certain other drugs, macrolides can increase the risk of sudden cardiac death in people who have long QT syndrome Torsades de Pointes Ventricular Tachycardia Torsades de pointes ventricular tachycardia is a specific type of ventricular tachycardia that occurs in people who have a particular disorder of the heart's electrical activity called a long... read more .
(See also Overview of Antibiotics Overview of Antibiotics Antibiotics are drugs used to treat bacterial infections. They are not effective against viral infections and most other infections. Antibiotics either kill bacteria or stop them from reproducing... read more .)
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 drug. (See also Drug Use During Pregnancy Drug Use During Pregnancy More than 50% of pregnant women take prescription or nonprescription (over-the-counter) drugs or use social drugs (such as tobacco and alcohol) or illicit drugs at some time during pregnancy... read more .)
Use of erythromycin during breastfeeding is generally considered acceptable. Whether other macrolides are safe to use during breastfeeding is unknown. (See also Drug Use During Breastfeeding Drug Use During Breastfeeding When mothers who are breastfeeding have to take a drug, they wonder whether they should stop breastfeeding. The answer depends on the following: How much of the drug passes into the milk Whether... read more .)