Description

Cefdinir is a third-generation cephalosporin antibiotic. It belongs to the beta-lactam class of antibiotics and is known for its broad-spectrum activity. It is a semi-synthetic drug that is administered orally. A key characteristic of third-generation cephalosporins like cefdinir is their enhanced activity against a wider range of Gram-negative bacteria compared to first- and second-generation cephalosporins, while still maintaining effectiveness against many Gram-positive bacteria.

Indications

Cefdinir is used to treat a variety of mild to moderate bacterial infections. Its main indications include:

• Community-acquired pneumonia (CAP): Caused by susceptible strains of bacteria, including Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis.
• Acute exacerbations of chronic bronchitis.
• Sinusitis.
• Pharyngitis/tonsillitis: Caused by susceptible strains of Streptococcus pyogenes.
• Skin and soft tissue infections: Caused by susceptible strains of Staphylococcus aureus and Streptococcus pyogenes.
• Otitis media (ear infections).

Mechanism of Action

Cefdinir, like other beta-lactam antibiotics, works by inhibiting bacterial cell wall synthesis. Its mechanism of action is as follows:

1. Bacterial Cell Wall Synthesis: Bacteria require a rigid cell wall, made of a polymer called peptidoglycan, for structural integrity and survival. The final stage of this synthesis involves a cross-linking process carried out by enzymes called penicillin-binding proteins (PBPs).
2. Beta-Lactam Ring: The key feature of cefdinir is its beta-lactam ring. This ring has a similar structure to the D-alanyl-D-alanine portion of the peptidoglycan precursor.
3. Inhibition of PBPs: Cefdinir acts by binding to and inhibiting these PBPs. By binding to the active site of the enzymes, it prevents them from cross-linking the peptidoglycan strands.
4. Resulting Effect: This inhibition leads to the formation of a weak and defective bacterial cell wall. The weakened wall cannot withstand the internal osmotic pressure of the bacterium, causing the cell to swell and burst, a process known as lysis. This leads to bacterial cell death, making cefdinir a bactericidal (bacteria-killing) antibiotic.