Omnicef
Omnicef - General Information
Omnicef (marketed by Abbott Laboratories under the brand name Omnicef) is a semi-synthetic, broad-spectrum antibiotic in the third generation of the cephalosporin class, proven effective for common bacterial infections of the ear, sinus, throat, and skin. It was approved by the U.S. Food and Drug Administration (FDA) in December of 1997.
Pharmacology of Omnicef
Omnicef is a third generation cephalosporin with a broad spectrum of activity against enteric gram-negative rods. Omnicef is stable in the presence of some, but not all, b-lactamase enzymes. As a result, many organisms resistant to penicillins and some cephalosporins are susceptible to cefdinir. Cephalosporins work the same way as penicillins: they interfere with the peptidoglycan synthesis of the bacterial wall by inhibiting the final transpeptidation needed for the cross-links. This effect is bactericidal.
Omnicef for patients
Patients should be counseled that antibacterial drugs including OMNICEF should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When OMNICEF is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by OMNICEF or other antibacterial drugs in the future.
Antacids containing magnesium or aluminum interfere with the absorption of cefdinir. If this type of antacid is required during OMNICEF therapy, OMNICEF should be taken at least 2 hours before or after the antacid.
Iron supplements, including multivitamins that contain iron, interfere with the absorption of cefdinir. If iron supplements are required during OMNICEF therapy, OMNICEF should be taken at least 2 hours before or after the supplement.
Iron-fortified infant formula does not significantly interfere with the absorption of cefdinir. Therefore, OMNICEF for Oral Suspension can be administered with iron-fortified infant formula.
Diabetic patients and caregivers should be aware that the oral suspension contains 2.86 g of sucrose per teaspoon.
Omnicef Interactions
Antacids (aluminum- or magnesium-containing)
Concomitant administration of 300-mg cefdinir capsules with 30 mL Maalox TC suspension reduces the rate (Cmax) and extent (AUC) of absorption by approximately 40%. Time to reach Cmax is also prolonged by 1 hour. There are no significant effects on cefdinir pharmacokinetics if the antacid is administered 2 hours before or 2 hours after cefdinir. If antacids are required during OMNICEF therapy, OMNICEF should be taken at least 2 hours before or after the antacid.
Probenecid
As with other b-lactam antibiotics, probenecid inhibits the renal excretion of cefdinir, resulting in an approximate doubling in A.C. a 54% increase in peak cefdinir plasma levels, and a 50% prolongation in the apparent elimination half-life.
Iron Supplements and Foods Fortified With Iron
Concomitant administration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron (as FeSO4) or vitamins supplemented with 10 mg of elemental iron reduced extent of absorption by 80% and 31%, respectively. If iron supplements are required during OMNICEF therapy, OMNICEF should be taken at least 2 hours before or after the supplement.
The effect of foods highly fortified with elemental iron (primarily iron-fortified breakfast cereals) on cefdinir absorption has not been studied.
Concomitantly administered iron-fortified infant formula (2.2 mg elemental iron/6 oz) has no significant effect on cefdinir pharmacokinetics. Therefore, OMNICEF for Oral Suspension can be administered with iron-fortified infant formula.
There have been rare reports of reddish stools in patients who have received cefdinir in Japan. The reddish color is due to the formation of a nonabsorbable complex between cefdinir or its breakdown products and iron in the gastrointestinal tract.
Drug/Laboratory Test Interactions
A false-positive reaction for ketones in the urine may occur with tests using nitroprusside, but not with those using nitroferricyanide. The administration of cefdinir may result in a false-positive reaction for glucose in urine using Clinitest, Benedictís solution, or Fehling's solution. It is recommended that glucose tests based on enzymatic glucose oxidase reactions (such as Clinistix or Tes-Tape) be used. Cephalosporins are known to occasionally induce a positive direct Coombsí test.
Omnicef Contraindications
OMNICEF (cefdinir) is contraindicated in patients with known allergy to the cephalosporin class of antibiotics.
Additional information about Omnicef
Omnicef Indication: For the treatment of the respiratory, skin, soft tissue, and ENT infections caused by H. influenzae (including b-lactamase producing strains), H. parainfluenzae (including b-lactamase producing strains), S. pneumoniae (penicillin-susceptible strains), S. pyogenes, S. aureus (including b-lactamase producing strains), and M. catarrhalis.
Mechanism Of Action: As with other cephalosporins, bactericidal activity of cefdinir results from inhibition of cell wall synthesis by acting on penicillin binding proteins (PBPs).
Drug Interactions: Not Available
Food Interactions: Take without regard to meals.
Avoid taking antacids at same time (up to 2 hours before or after antibiotic).
Avoid taking iron preparations at same time (up to 2 hours before or after antibiotic).
Generic Name: Cefdinir
Synonyms: CFDN; Cefdirnir
Drug Category: Anti-Infectives; Anti-Bacterial Agents
Drug Type: Small Molecule; Approved
Other Brand Names containing Cefdinir: Cefzon; Omnicef;
Absorption: Maximal plasma cefdinir concentrations occur 2 to 4 hours postdose following capsule or suspension administration. Estimated bioavailability of cefdinir capsules is 21% following administration of a 300 mg capsule dose, and 16% following administration of a 600 mg capsule dose. Estimated absolute bioavailability of cefdinir suspension is 25%. Absorption is reduced by approximately 15% when administered with a high fat meal.
Toxicity (Overdose): Information on cefdinir overdosage in humans is not available. In acute rodent toxicity studies, a single oral 5600-mg/kg dose produced no adverse effects. Toxic signs and symptoms following overdosage with other b-lactam antibiotics have included nausea, vomiting, epigastric distress, diarrhea, and convulsions.
Protein Binding: 60%-70%, binding is independent of concentration.
Biotransformation: Cefdinir is not appreciably metabolized. Activity is primarily due to parent drug.
Half Life: 1.7 ± 0.6 hours
Dosage Forms of Omnicef: Capsule Oral
Powder, for suspension Oral
Chemical IUPAC Name: (6R,7R)-7-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-hydroxyiminoacetyl]amino]-3-ethenyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid
Chemical Formula: C14H13N5O5S2
Cefdinir on Wikipedia: https://en.wikipedia.org/wiki/Cefdinir
Organisms Affected: Enteric gram-negative rods