Omnicef (cefdinir) is a third-generation oral cephalosporin antibiotic indicated for the treatment of susceptible bacterial infections. It demonstrates broad-spectrum activity against both Gram-positive and Gram-negative pathogens, offering a reliable option for clinicians managing community-acquired infections. Its once- or twice-daily dosing regimen supports patient adherence, while its well-established efficacy and safety profile make it a trusted choice in outpatient and inpatient settings. This comprehensive guide details the pharmacological characteristics, clinical applications, and practical considerations for healthcare providers prescribing Omnicef.

Features

• Active ingredient: Cefdinir 300 mg or 125 mg per capsule/5 mL suspension
• Pharmacologic class: Third-generation cephalosporin antibiotic
• Spectrum: Broad activity against Gram-positive (e.g., Staphylococcus aureus, Streptococcus pneumoniae) and Gram-negative bacteria (e.g., Haemophilus influenzae, Moraxella catarrhalis)
• Administration: Oral formulation (capsules and powder for oral suspension)
• Dosing frequency: Once or twice daily, depending on indication and renal function
• Bioavailability: Approximately 21–25%, unaffected by food
• Half-life: 1.7 hours in adults with normal renal function

Benefits

• Effective against common respiratory, skin, and soft tissue pathogens
• Convenient dosing schedule improves patient compliance
• Generally well-tolerated with a low incidence of serious adverse effects
• Suitable for pediatric and adult populations
• Low potential for drug interactions compared to other antibiotic classes
• Does not require refrigeration after reconstitution (suspension stable for 10 days at room temperature)

Common use

Omnicef is commonly prescribed for the treatment of mild to moderate infections caused by susceptible strains of bacteria. Typical indications include community-acquired pneumonia, acute exacerbations of chronic bronchitis, acute bacterial sinusitis, pharyngitis/tonsillitis, uncomplicated skin and skin structure infections, and acute otitis media. Its spectrum makes it particularly useful in outpatient settings where coverage for beta-lactamase-producing organisms is desired.

Dosage and direction

Adults and adolescents (≥13 years):

• Community-acquired pneumonia: 300 mg orally every 12 hours for 10 days
• Acute bacterial sinusitis: 300 mg every 12 hours or 600 mg once daily for 10 days
• Acute exacerbations of chronic bronchitis: 300 mg every 12 hours for 5–10 days
• Pharyngitis/tonsillitis: 300 mg every 12 hours for 5–10 days or 600 mg once daily for 10 days
• Skin and skin structure infections: 300 mg every 12 hours for 10 days

Pediatric patients (6 months–12 years):
Dosing based on 7 mg/kg orally every 12 hours or 14 mg/kg once daily, depending on indication. Maximum dose should not exceed 600 mg per day.

Dosage adjustment is required in patients with renal impairment (creatinine clearance <30 mL/min).

Precautions

• Use with caution in patients with a history of gastrointestinal disease, particularly colitis
• May cause false-positive reactions for glucose in urine with certain testing methods (e.g., Benedict’s solution)
• Prolonged use may result in overgrowth of nonsusceptible organisms
• Should be prescribed with care in patients with known hypersensitivity to beta-lactam antibiotics
• Not recommended for the treatment of meningitis due to inadequate cerebrospinal fluid penetration

Contraindications

• Known hypersensitivity to cefdinir, other cephalosporins, or any component of the formulation
• Patients with a history of severe immediate hypersensitivity reactions (e.g., anaphylaxis) to penicillins or other beta-lactam antibiotics

Possible side effect

Common adverse reactions (≥1%) include diarrhea, nausea, headache, vaginal moniliasis, abdominal pain, and rash. Less frequently reported effects include vomiting, dyspepsia, flatulence, dizziness, and elevated liver enzymes. As with other antibiotics, Clostridium difficile-associated diarrhea and pseudomembranous colitis have been reported. Allergic reactions ranging from mild skin eruptions to anaphylaxis may occur.

Drug interaction

• Antacids containing magnesium or aluminum: May decrease absorption of cefdinir; separate administration by at least 2 hours
• Iron supplements and iron-fortified foods: May reduce absorption and cause reddish stools (harmless discoloration)
• Probenecid: May increase and prolong cefdinir blood levels
• No clinically significant interactions with warfarin reported in clinical studies

Missed dose

If a dose is missed, it should be taken as soon as possible. However, if it is almost time for the next dose, the missed dose should be skipped and the regular dosing schedule resumed. Doubling the dose is not recommended.

Overdose

No specific antidote exists. Gastric lavage may be considered if ingestion was recent. Hemodialysis may remove cefdinir from the circulation. Supportive care and monitoring of renal function are recommended in cases of significant overdose.

Storage

• Store capsules at controlled room temperature (20–25°C) in a tightly closed container
• Reconstituted oral suspension may be stored at room temperature; discard after 10 days
• Keep out of reach of children and protected from light and moisture

Disclaimer

This information is intended for healthcare professionals and should not replace clinical judgment. Prescribing decisions should be based on the individual patient’s condition, susceptibility patterns, and local prescribing guidelines. Always verify the most current prescribing information before administration.

Reviews

Clinical studies and post-marketing surveillance indicate that Omnicef is generally effective and well-tolerated. In comparative trials, it demonstrated similar efficacy to other oral cephalosporins and macrolides for approved indications. Pediatric studies have shown acceptable tolerability, with diarrhea being the most frequently reported adverse event. Many clinicians appreciate its convenient dosing and reliable coverage for common community-acquired pathogens.