Cephalosporins

Cephalosporins are a large and widely used class of antimicrobial medications that belong to the beta-lactam antibiotic family. They are commonly prescribed to treat a broad range of bacterial infections, from mild skin infections to serious, life-threatening illnesses such as meningitis and bloodstream infections. Cephalosporins are valued for their broad-spectrum activity, predictable effectiveness, and generally good safety profile.

Cephalosporins are closely related to penicillin and share a similar chemical structure. Over time, newer generations of cephalosporins have been developed to expand activity against gram-negative bacteria and improve resistance to bacterial enzymes called beta-lactamases. Because of this, cephalosporins remain an essential tool in infectious diseases for both adults and pediatric patients.

Cephalosporins are beta-lactam antibiotics that kill bacteria by interfering with bacterial cell wall synthesis. The cell wall is essential for bacterial survival, and damage to it causes the bacteria to break apart and die. Because of this action, cephalosporins are considered bactericidal antibiotics.

These drugs are effective against many gram-positive and gram-negative bacteria, including common pathogens such as streptococci, staphylococci, Escherichia coli, Enterobacter, and Klebsiella pneumoniae. Their exact spectrum of activity depends on the specific generation of cephalosporin used.

Cephalosporins work by binding to proteins involved in building the bacterial cell wall. This disrupts cell wall formation and leads to bacterial death. This mechanism is similar to how penicillin and other beta-lactam antibiotics work.

Some bacteria produce enzymes called beta-lactamases that can break down antibiotics. Later-generation cephalosporins are more resistant to these enzymes, giving them extended-spectrum activity against gram-negative bacilli and other resistant organisms. Differences in side chain structure help determine resistance patterns, the spectrum of activity, and cross-reactivity with penicillin.

Cephalosporins are grouped into generations based on their antibacterial spectrum, resistance to beta-lactamases, and typical clinical use. Each generation has different activities against gram-positive and gram-negative bacteria.

First-generation cephalosporins

These have strong activity against gram-positive bacteria and limited gram-negative coverage. They are commonly used for skin, soft tissue, and uncomplicated urinary tract infections.

• Cephalexin (Keflex).

• Cefadroxil (Duricef).

• Cefazolin (Ancef).

Second-generation cephalosporins

These provide improved gram-negative coverage while maintaining activity against gram-positive organisms. Some also have anaerobic activity.

• Cefuroxime (Ceftin, Zinacef).

• Cefaclor (Ceclor).

• Cefprozil (Cefzil).

• Cefoxitin (Mefoxin).

• Cefotetan (Cefotan).

Third-generation cephalosporins

These agents have extended-spectrum activity against gram-negative bacteria and improved central nervous system penetration, making them useful for serious infections.

Ceftriaxone (Rocefin).

Cefotaxime (Claforan).

Ceftazidime (Fortaz, Tazicef).

Cefixime (Suprax).

Cefpodoxime (Vantin).

Cefdinir (Omnicef).

Cefoperazone (Cefobid).

Ceftibuten (Cedax).

Fourth-generation cephalosporins

Fourth-generation cephalosporins combine strong gram-positive activity with enhanced gram-negative coverage, including resistant organisms.

• Cefepime (Maxipime).

Fifth-generation cephalosporins

These agents are notable for activity against methicillin-resistant Staphylococcus aureus.

• Ceftaroline (Teflaro).

Advanced and specialty cephalosporins

These newer agents are used primarily in hospital settings for resistant gram-negative infections.

Cefiderocol (Fetroja).

Ceftobiprole (Zevtera).

Ceftolozane/tazobactam (Zerbaxa).

Cephalosporins are used to treat a wide range of bacterial infections.

Common uses include:

• Skin and soft tissue infections.

• Respiratory tract infections.

• Urinary tract infections.

• Bone and joint infections.

• Meningitis and other central nervous system infections.

• Sexually transmitted infections such as gonorrhea.

Cephalosporins are also used for surgical prophylaxis to prevent infections and are frequently prescribed in children due to their safety profile.

Cephalosporins are also chosen based on which bacteria are causing the infection and how severe it is.

First- and second-generation cephalosporins are commonly used for aerobic infections caused by Streptococcus, Streptococcus pneumoniae, Proteus, and Escherichia coli (E. coli), especially in skin, respiratory, and urinary tract infections.

Oral cephalosporins are often used for mild to moderate infections caused by Haemophilus influenzae, Neisseria species, and other common Enterobacteriaceae.

Third-generation cephalosporins such as ceftriaxone are widely used for serious infections, including meningitis, bloodstream infections, and gonorrhea due to Neisseria.

Ceftazidime and cefepime are effective against Pseudomonas aeruginosa, a difficult-to-treat gram-negative organism often seen in hospital settings.

Cephamycins like cefoxitin and cefotetan provide added anaerobic coverage for abdominal infections.

While most cephalosporins do not treat MRSA, the fifth-generation agent ceftaroline is a β-lactam antibiotic with activity against methicillin-resistant Staphylococcus aureus.

Common side effects from the use of cephalosporins include:

• Nausea, vomiting, or diarrhea.

• Mild skin rash.

• Injection site reactions with parenteral use.

Less common but serious adverse effects include allergic reactions, hypersensitivity, and anaphylaxis. Changes in kidney function may occur, especially in people with underlying renal disease or when high doses are used.

These are not all of the possible side effects of cephalosporins. You should always seek medical advice from your healthcare provider for any questions or concerns about your medical condition or treatment. Read all patient information, medication guides, or drug information sheets that come with this medication. You can also report adverse effects to the Food and Drug Administration at www.fda.gov/medwatch or 1-800-FDA-1088.

Although these medications are generally well-tolerated and safe, there are certain warnings, precautions, and drug interactions you should be aware of.

Warnings

Before starting cephalosporins, it is crucial to discuss any existing health conditions with your healthcare provider. You should be sure that your healthcare provider is aware of all your medical conditions, including:

• A history of allergic reactions to penicillin or other beta-lactam antibiotics.

• Kidney or renal disease.

• Previous severe antibiotic reactions.

Cross-reactivity between penicillin and cephalosporins is low but possible.

Contraindications

Cephalosporins should not be used in people with a known severe hypersensitivity or anaphylaxis to cephalosporins. Caution is advised in those with severe penicillin allergy.

Drug interactions

When cephalosporins are taken with other prescription drugs, over-the-counter medications, vitamins, and supplements, it may change how they work or increase the frequency or severity of side effects. Make sure that you tell your healthcare professional about anything that you are taking to avoid any negative drug interactions, including:

Other nephrotoxic drugs, such as aminoglycosides, may increase kidney risk.

Certain anticoagulants, such as warfarin which may increase bleeding risk.

Alcohol use while taking a cephalosporin may increase the risk of adverse effects.