Generic Name

Omnicef

Brand Names

for *cefdinir*, a third‑generation oral cephalosporin used to treat a variety of bacterial infections. It has a wide spectrum of activity against gram‑negative and gram‑positive organisms, including *Streptococcus pneumoniae*, *Streptococcus pyogenes*, and many anaerobes.

Mechanism

Cephalosporins inhibit bacterial cell wall synthesis by binding to *penicillin‑binding proteins* (PBPs).
• Cefdinir competes with native d‑alanine‑d‑alanine termini, preventing transpeptidation in peptidoglycan cross‑linking.
• This leads to osmotic instability and cell lysis, primarily affecting actively dividing bacteria.
• Its activity is unaffected by many β‑lactamases that deactivate earlier cephalosporins.

Pharmacokinetics

Indications

• Acute otitis media (children 6 months–12 y)
• Pharyngitis and cervical lymphadenitis caused by *S. pyogenes* (both adults and children)
• Community‑acquired bacterial pneumonia (≥ 45 y when *S. pneumoniae* suspected)
• Upper and lower respiratory tract infections (chronic sinusitis, bronchitis)
• Lung abscess, pleural empyema, and tuberculous pleuritis (adjunct to standard antituberculous therapy)
• Dental and maxillofacial infections
• Skin and skin‑structure infections (including cellulitis)

*Note:* In vitro activity against community‑acquired *Pseudomonas* and *Enterobacter* spp. is limited; not the first choice for hospital‑acquired infections.

Contraindications

• Allergy to cephalosporins, penicillins, or other β‑lactams.
• Severe renal impairment (CrCl < 30 mL/min) – therapy contraindicated.
• History of hypersensitivity reactions (e.g., Stevens–Johnson syndrome).
• Pregnancy – category B; uncertain benefit versus risk.
• Post‑menopausal osteoporosis – may exacerbate bone loss; monitor bone density if treated long‑term.

Dosing

• Take with meals to improve tolerability.
• Swallow tablets whole; do not crush or chew.
• Store at room temperature, protect from moisture.

Adverse Effects

Monitoring

• Renal function (CrCl) before initiation and every 2 weeks in CKD patients.
• Baseline and periodic CBC if treatment > 30 days to detect bicytopenia.
• Liver transaminases if prolonged therapy or concomitant hepatotoxic drugs.
• Clinical response to infection – resolution of fever, pain, and cultures if applicable.
• Adverse drug reactions: GI upset, rash, or signs of infection.

Clinical Pearls

• Bioavailability increases with dose – consider 600 mg for severe pneumonia or if high drug exposure is needed.
• Take with food to mitigate stomach upset and avoid “acid peptic disease” in patients with GERD.
• Avoid in patients with penicillin allergy: cross‑reactivity ~5 % – older risk estimates over‑estimated; still a precaution in severe allergic history.
• Use shorter courses (5 d) for uncomplicated otitis media if patient responds early– reduces super‑infection risk.
• Be vigilant in post‑menopausal women: chronic use can contribute to bone density loss; supplement calcium/vitamin D when long‑term.
• Drug interactions: minimal; however, cefuroxime may reduce activity of rabeprazole—not a concern with cefdinir.
• With renal impairment simply reduce dose—no need for extended interval dosing (e.g., q24 h) due to predictable half‑life.
• Keep patient education on recognizing signs of c. difficile (watery diarrhea) especially after prior antibiotic courses.

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• *This drug card is intended for educational purposes and should not replace comprehensive clinical guidelines or institutional protocols.*