cefdinir
Omnicef

Pharmacologic classification: third-generation cephalosporin
Therapeutic classification: antibiotic
Pregnancy risk category B


Available forms
Available by prescription only
Capsules: 300 mg
Suspension: 125 mg/5 ml

Indications and dosages
 Mild to moderate infection caused by susceptible strains of microorganisms resulting in community-acquired pneumonia, acute exacerbations of chronic bronchitis, acute maxillary sinusitis, acute bacterial otitis media, and uncomplicated skin and skin-structure infections. Adults and adolescents age 13 and older: 300 mg P.O. q 12 hours or 600 mg P.O. q 24 hours for 10 days. (Use q-12-hour doses for pneumonia and skin infections.)
Children ages 6 months to 12 years: 7 mg/kg P.O. q 12 hours or 14 mg/kg P.O. q 24 hours for 10 days, up to maximum dose of 600 mg daily. (Use q-12-hour dosages for skin infections.)
 Pharyngitis, tonsillitis. Adults and adolescents age 13 and older: 300 mg P.O. q 12 hours for 5 to 10 days or 600 mg P.O. q 24 hours for 10 days.
Children ages 6 months to 12 years: 7 mg/kg P.O. q 12 hours for 5 to 10 days or 14 mg/kg P.O. q 24 hours for 10 days.
≡ Dosage adjustment. If creatinine clearance is less than 30 ml/minute, reduce dosage to 300 mg P.O. once daily for adults and 7 mg/kg P.O. (up to 300 mg) once daily for children. If patient undergoes long-term hemodialysis, give 300 mg or 7 mg/kg P.O. at end of each dialysis session and subsequently every other day.

Pharmacodynamics
Antibiotic action: The bactericidal activity of cefdinir results from inhibition of cell wall synthesis. Drug is stable in the presence of some beta-lactamase enzymes, causing some microorganisms resistant to penicillins and cephalosporins to be susceptible to cefdinir. Excluding Pseudomonas, Enterobacter, Enterococcus, and methicillin-resistant Staphylococcus species, the spectrum of activity of cefdinir includes a broad range of gram-positive and gram-negative aerobic microorganisms.

Pharmacokinetics
Absorption: Estimated bioavailability of drug is 21% following a 300-mg capsule dose, 16% following a 600-mg capsule dose, and 25% for the suspension.
Distribution: Mean volume of distribution for adults and children is 0.35 and 0.67 L/kg, respectively, and distribution to tonsil, sinus, lung, and middle ear tissue and fluid ranges from 15% to 35% of corresponding plasma levels. About 60% to 70% is bound to plasma proteins; binding is independent of concentration.
Metabolism: Not appreciably metabolized; its activity is caused mainly by parent drug.
Excretion: Excreted mainly by kidneys; mean plasma elimination half-life is 1.7 hours. Drug clearance is reduced in patients with renal dysfunction.

Route Onset Peak Duration
P.O. Unknown 2-4 hr Unknown


Contraindications and precautions
Contraindicated in patients allergic to cephalosporin class of antibiotics. Use cautiously in patients hypersensitive to penicillin because of possible cross-sensitivity with other beta-lactam antibiotics. Also use cautiously in patients with a history of colitis.

Interactions
Drug-drug. Antacids that contain aluminum or magnesium, iron supplements: Decreases absorption and bioavailability of cefdinir. Give these drugs 2 hours before or after cefdinir dose.
Probenecid: Inhibits renal secretion of cefdinir. Monitor patient.
Drug-food. Foods fortified with iron, such as infant formula: Decreases absorption and bioavailability of cefdinir. Monitor patient.

Adverse reactions
CNS: headache.
GI: abdominal pain, diarrhea, nausea, vomiting.
GU: vaginal candidiasis, vaginitis.
Skin: rash.

Effects on lab test results
• May increase GGT and alkaline phosphatase levels.

Overdose and treatment
No information available. Evidence of overdose with other beta-lactam antibiotics includes nausea, vomiting, epigastric distress, diarrhea, and seizures.
 Drug is removed by hemodialysis.

Special considerations
• Pseudomembranous colitis has been reported with many antibiotics, including cefdinir, and should be considered in patients whose symptoms include diarrhea subsequent to antibiotic therapy or in those with history of colitis.
• False-positive reactions for ketones (tests using nitroprusside only) and glucose (Clinitest, Benedict’s solution, Fehling’s solution) in the urine have been reported. Generally, cephalosporins can induce a positive direct Coombs’ test.
• In patient with renal impairment, monitor renal function before and during therapy.
• As with many antibiotics, prolonged drug treatment may result in possible emergence and overgrowth of resistant organisms. Monitor patient for superinfection and consider alternative therapy if it occurs.
Breast-feeding patients
• Drug isn’t detectable in breast milk after 600-mg doses.
Pediatric patients
• Safety and efficacy in infants younger than age 6 months haven’t been established. Pharmacokinetic data for children are comparable to data for adults.
Geriatric patients
• Cefdinir is well tolerated in all age-groups. Safety and efficacy are comparable in elderly and younger patients. Dosage adjustment isn’t needed unless patient has renal impairment.

Patient education
• Instruct patient to take antacids, iron supplements, and iron-fortified foods 2 hours before or after a cefdinir dose.
• Inform diabetic patient that each teaspoon of suspension contains 2.86 g of sucrose.
• Advise patient to report severe diarrhea or diarrhea accompanied by abdominal pain.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use