CEDAX®

(ceftibuten capsules) and (ceftibuten for oral suspension)

FOR ORAL USE ONLY

PRODUCT INFORMATION

DESCRIPTION:

CEDAX (ceftibuten capsules) and (ceftibuten for oral suspension) contain the active ingredient ceftibuten as ceftibuten dihydrate. Ceftibuten dihydrate is a semisynthetic cephalosporin antibiotic for oral administration. Chemically, it is (+)-(6R,7R)-7-[(Z)-2-(2-Amino-4-thiazolyl)-4-carboxycrotonamido]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, dihydrate. Its molecular formula is C15H14N4O6S2•2H2O. Its molecular weight is 446.43 as the dihydrate.

Ceftibuten dihydrate has the following structural formula:

CEDAX Capsules contain ceftibuten dihydrate equivalent to 400 mg of ceftibuten. Inactive ingredients contained in the capsule formulation include: magnesium stearate, microcrystalline cellulose, and sodium starch glycolate. The capsule shell and/or band contains gelatin, sodium lauryl sulfate, titanium dioxide, and polysorbate 80. The capsule shell may also contain benzyl alcohol, sodium propionate, edetate calcium disodium, butylparaben, propylparaben, and methylparaben.

CEDAX Oral Suspension after reconstitution contains ceftibuten dihydrate equivalent to 90 mg of ceftibuten per 5 mL. CEDAX Oral Suspension is cherry flavored and contains the inactive ingredients: cherry flavoring, polysorbate 80, silicon dioxide, simethicone, sodium benzoate, sucrose (approximately 1 g/5 mL), titanium dioxide, and xanthan gum.

CLINICAL PHARMACOLOGY:

PHARMACOKINETICS

Absorption:

CEDAX CAPSULES

Ceftibuten is rapidly absorbed after oral administration of CEDAX Capsules. The plasma concentrations and pharmacokinetic parameters of ceftibuten after a single 400-mg dose of CEDAX Capsules to 12 healthy adult male volunteers (20 to 39 years of age) are displayed in the table below. When CEDAX Capsules were administered once daily for 7 days, the average Cmax was 17.9 µg/mL on day 7. Therefore, ceftibuten accumulation in plasma is about 20% at steady state.

CEDAX ORAL SUSPENSION

Ceftibuten is rapidly absorbed after oral administration of CEDAX Oral Suspension. The plasma concentrations and pharmacokinetic parameters of ceftibuten after a single 9-mg/kg dose of CEDAX Oral Suspension to 32 fasting pediatric patients (6 months to 12 years of age) are displayed in the following table:

The absolute bioavailability of CEDAX Oral Suspension has not been determined. The plasma concentrations of ceftibuten in pediatric patients are dose proportional following single doses of CEDAX Capsules of 200 mg and 400 mg and of CEDAX Oral Suspension between 4.5 mg/kg and 9 mg/kg.

Distribution:

CEDAX CAPSULES

The average apparent volume of distribution (V/F) of ceftibuten in 6 adult subjects is 0.21 L/kg (± 1 SD = 0.03 L/kg).

CEDAX ORAL SUSPENSION

The average apparent volume of distribution (V/F) of ceftibuten in 32 fasting pediatric patients is 0.5 L/kg (± 1 SD = 0.2 L/kg).

Protein Binding:

Ceftibuten is 65% bound to plasma proteins. The protein binding is independent of plasma ceftibuten concentration.

Tissue Penetration:

Bronchial secretions:

In a study of 15 adults administered a single 400-mg dose of ceftibuten and scheduled to undergo bronchoscopy, the mean concentrations in epithelial lining fluid and bronchial mucosa were 15% and 37%, respectively, of the plasma concentrations.

Sputum:

Ceftibuten sputum levels average approximately 7% of the concomitant plasma ceftibuten level. In a study of 24 adults administered ceftibuten 200 mg bid or 400 mg qd, the average Cmax in sputum (1.5 µg/mL) occurred at 2 hours postdose and the average Cmax in plasma (17 µg/mL) occurred at 2 hours postdose.

Middle-ear fluid (MEF):

In a study of 12 pediatric patients administered 9 mg/kg, ceftibuten MEF area under the curve (AUC) averaged approximately 70% of the plasma AUC. In the same study, Cmax values were 14.3 ± 2.7 µg/mL in MEF at 4 hours postdose and 14.5 ± 3.7 µg/mL in plasma at 2 hours postdose.

Tonsillar tissue:

Data on ceftibuten penetration into tonsillar tissue are not available.

Cerebrospinal fluid:

Data on ceftibuten penetration into cerebrospinal fluid are not available.

Metabolism and Excretion:

A study with radiolabeled ceftibuten administered to 6 healthy adult male volunteers demonstrated that cis-ceftibuten is the predominant component in both plasma and urine. About 10% of ceftibuten is converted to the trans-isomer. The trans-isomer is approximately ⅛ as antimicrobially potent as the cis-isomer.

Ceftibuten is excreted in the urine; 95% of the administered radioactivity was recovered either in urine or feces. In 6 healthy adult male volunteers, approximately 56% of the administered dose of ceftibuten was recovered from urine and 39% from the feces within 24 hours. Because renal excretion is a significant pathway of elimination, patients with renal dysfunction and patients undergoing hemodialysis require dosage adjustment (see DOSAGE AND ADMINISTRATION).

Food Effect on Absorption:

Food affects the bioavailability of ceftibuten from CEDAX Capsules and CEDAX Oral Suspension.

The effect of food on the bioavailability of CEDAX Capsules was eva luated in 26 healthy adult male volunteers who ingested 400-mg of CEDAX Capsules after an overnight fast or immediately after a standardized breakfast. Results showed that food delays the time of Cmax by 1.75 hours, decreases the Cmax by 18%, and decreases the extent of absorption (AUC) by 8%.

The effect of food on the bioavailability of CEDAX Oral Suspension was eva luated in 18 healthy adult male volunteers who ingested 400 mg of CEDAX Oral Suspension after an overnight fast or immediately after a standardized breakfast. Results obtained demonstrated a decrease in Cmax of 26% and an AUC of 17% when CEDAX Oral Suspension was administered with a high-fat breakfast, and a decrease in Cmax of 17% and an AUC of 12% when CEDAX Oral Suspension was administered with a low-calorie nonfat breakfast (see PRECAUTIONS).

Bioequivalence of Dosage Formulations:

A study in 18 healthy adult male volunteers demonstrated that a 400-mg dose of CEDAX Capsules produced equivalent concentrations to a 400-mg dose of CEDAX Oral Suspension. Average Cmax values were 15.6 (3.1) µg/mL for the capsule and 17.0 (3.2) µg/mL for the suspension. Average AUC values were 80.1 (14.4) µg∙hr/mL for the capsule and 87.0 (12.2) µg∙hr/mL for the suspension.

Special Populations:

Geriatric patients:

Ceftibuten pharmacokinetics have been investigated in elderly (65 years of age and older) men (n = 8) and women (n = 4). Each volunteer received ceftibuten 200-mg capsules twice daily for 3½ days. The average Cmax was 17.5 (3.7) µg/mL after 3½ days of dosing compared to 12.9 (2.1) µg/mL after the first dose; ceftibuten accumulation in plasma was 40% at steady state. Information regarding the renal function of these volunteers was not available; therefore, the significance of this finding for clinical use of CEDAX Capsules in elderly patients is not clear. Ceftibuten dosage adjustment in elderly patients may be necessary (see DOSAGE AND ADMINISTRATION).

Patients with renal insufficiency:

Ceftibuten pharmacokinetics have been investigated in adult patients with renal dysfunction. The ceftibuten plasma half-life increased and apparent total clearance (Cl/F) decreased proportionately with increasing degree of renal dysfunction. In 6 patients with moderate renal dysfunction (creatinine clearance 30 to 49 mL/min), the plasma half-life of ceftibuten increased to 7.1 hours and Cl/F decreased to 30 mL/min. In 6 patients with severe renal dysfunction (creatinine clearance 5 to 29 mL/min), the half-life increased to 13.4 hours and Cl/F decreased to 16 mL/min. In 6 functionally anephric patients (creatinine clearance <5 mL/min), the half-life increased to 22.3 hours and Cl/F decreased to 11 mL/min (a 7- to 8-fold change compared to healthy volunteers). Hemodialysis removed 65% of the drug from the blood in 2 to 4 hours. These changes serve as the basis for dosage adjustment recommendations in adult patients with mild to severe renal dysfunction (see DOSAGE AND ADMINISTRATION).

Microbiology:

Ceftibuten exerts its bactericidal action by binding to essential target proteins of the bacterial cell wall. This binding leads to inhibition of cell-wall synthesis.

Ceftibuten is stable in the presence of most plasmid-mediated beta-lactamases, but it is not stable in the presence of chromosomally-mediated cephalosporinases produced in organisms such as Bacteroides, Citrobacter, Enterobacter, Morganella, and Serratia. Like other beta-lactam agents, ceftibuten should not be used against strains resistant to beta-lactams due to general mechanisms such as permeability or penicillin-binding protein changes like penicillin-resistant S. pneumoniae.

Ceftibuten has been shown to be active against most strains of the following organisms both in vitro and in clinical infections (see INDICATIONS AND USAGE):

Gram-positive aerobes:  Streptococcus pneumoniae (penicillin-susceptible strains only) Streptococcus pyogenes

Gram-negative aerobes: Haemophilus influenzae (including β-lactamase-producing strains) Moraxella catarrhalis (including β-lactamase-producing strains)

There are no known organisms which are potential pathogens in the indications approved for ceftibuten for which ceftibuten exhibits in vitro activity but for which the safety and efficacy of ceftibuten in treating clinical infections due to these organisms, have not been established in adequate and well-controlled trials.

NOTE: Ceftibuten is INACTIVE in vitro against Acinetobacter, Bordetella, Campylobacter, Enterobacter, Enterococcus, Flavobacterium, Hafnia, Listeria, Pseudomonas, Staphylococcus, and Streptococcus (except pneumoniae and pyogenes) species. In addition, it shows little in vitro activity against most anaerobes, including most species of Bacte