Cephalosporins

ByBrian J. Werth, PharmD, University of Washington School of Pharmacy
Reviewed/Revised May 2024
VIEW PROFESSIONAL VERSION

Cephalosporins are a subclass of antibiotics called beta-lactam antibiotics (antibiotics that have a chemical structure called a beta-lactam ring). Beta-lactam antibiotics also include carbapenems, monobactams, and penicillins.

There are several classifications or generations of cephalosporins. The different generations are effective against different types of bacteria.

Most bacteria have an outer covering (cell wall) that protects them. Like the other beta-lactam antibiotics, cephalosporins work by preventing bacteria from forming this cell wall, resulting in death of the bacteria.

Because cephalosporins are structurally similar to the penicillins, some people who have an allergic reaction to penicillins may have an allergic reaction to certain cephalosporins. A health care professional can help assess the risk of allergic cross-reactivity between specific antibiotics in people who believe they have had an allergic reaction.

Table

(See also Overview of Antibiotics.)

Use of Cephalosporins During Pregnancy and Breastfeeding

Cephalosporins are among the safest antibiotics to use during pregnancy but are not without risks. Each medication is slightly different and may have different side effects. (See also Safety of Medications During Pregnancy.)

Use of cephalosporins during breastfeeding is discouraged because these medications may affect the baby's digestive tract. (See also Medication and Substance Use During Breastfeeding.)

quizzes_lightbulb_red
Test your KnowledgeTake a Quiz!
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID