Cefprozil is a semi-synthetic broad-spectrum cephalosporin antibiotic.

Cefprozil is a cis and trans isomeric mixture (≥90% cis). The chemical name for the monohydrate is (6R,7R)-7-[(R)-2-amino-2-(p-hydroxyphenyl)acetamido]-8-oxo-3-propenyl-5-thia-1-azabicyclo [4.2.0]oct-2-ene-2- carboxylic acid monohydrate, and the structural formula is:

Cefprozil is a white to yellowish powder with a molecular formula for the monohydrate of C18H19N3O5S.H2O and a molecular weight of 407.45.

Cefprozil for oral suspension is intended for oral administration.

Cefprozil for oral suspension contains cefprozil equivalent to 125 mg or 250 mg of anhydrous cefprozil per 5 mL constituted suspension.  In addition, the oral suspension contains the following inactive ingredients: aspartame, bubble gum flavor, anhydrous citric acid, colloidal silicon dioxide, FD&C Red No. 40 Aluminum Lake, glycine, microcrystalline cellulose and sodium carboxymethylcellulose, sodium benzoate, sodium chloride and sucrose.

The pharmacokinetic data were derived from the capsule formulation; however, bioequivalence has been demonstrated for the oral solution, capsule, tablet, and suspension formulations under fasting conditions.

Following oral administration of cefprozil to fasting subjects, approximately 95% of the dose was absorbed. The average plasma half-life in normal subjects was 1.3 hours, while the steady-state volume of distribution was estimated to be 0.23 L/kg. The total body clearance and renal clearance rates were approximately 3 mL/min/kg and 2.3 mL/min/kg, respectively.

Average peak plasma concentrations after administration of 250 mg, 500 mg, or 1 g doses of cefprozil to fasting subjects were approximately 6.1, 10.5, and 18.3 mcg/mL, respectively, and were obtained within 1.5 hours after dosing. Urinary recovery accounted for approximately 60% of the administered dose. (See Table.)

During the first 4 hour period after drug administration, the average urine concentrations following 250 mg, 500 mg, and 1 g doses were approximately 700 mcg/mL, 1000 mcg/mL, and  2900 mcg/mL, respectively.

Administration of cefprozil with food did not affect the extent of absorption (AUC) or the peak plasma concentration (Cmax) of cefprozil. However, there was an increase of 0.25 to 0.75 hours in the time to maximum plasma concentration of cefprozil (Tmax).

The bioavailability of the capsule formulation of cefprozil was not affected when administered 5 minutes following an antacid.

Plasma protein binding is approximately 36% and is independent of concentration in the range of 2 mcg/mL to 20 mcg/mL.

There was no evidence of accumulation of cefprozil in the plasma in individuals with normal renal function following multiple oral doses of up to 1000 mg every 8 hours for 10 days.

In patients with reduced renal function, the plasma half-life may be prolonged up to 5.2 hours depending on the degree of the renal dysfunction. In patients with complete absence of renal function, the plasma half-life of cefprozil has been shown to be as long as 5.9 hours. The half-life is shortened during hemodialysis. Excretion pathways in patients with markedly impaired renal function have not been determined. (See PRECAUTIONS  and DOSAGE AND ADMINISTRATION.)

In patients with impaired hepatic function, the half-life increases to approximately 2 hours. The magnitude of the changes does not warrant a dosage adjustment for patients with impaired hepatic function.

Healthy geriatric volunteers (≥65years old) who received a single 1 g dose of cefprozil had 35% to 60% higher AUC and 40% lower renal clearance values compared with healthy adult volunteers 20 to 40 years of age. The average AUC in young and elderly female subjects was approximately 15% to 20% higher than in young and elderly male subjects. The magnitude of these age- and gender-related changes in the pharmacokinetics of cefprozil is not sufficient to necessitate dosage adjustments.

Adequate data on CSF levels of cefprozil are not available.

Comparable pharmacokinetic parameters of cefprozil are observed between pediatric patients                (6 months to 12 years) and adults following oral administration of selected matched doses. The maximum concentrations are achieved at 1to 2 hours after dosing. The plasma elimination half-life is approximately 1.5 hours. In general, the observed plasma concentrations of cefprozil in pediatric patients at the 7.5, 15, and 30 mg/kg doses are similar to those observed within the same time frame in normal adult subjects at the 250, 500, and 1000 mg doses, respectively. The comparative plasma concentrations of cefprozil in pediatric patients and adult subjects at the equivalent dose level are presented in the table below.

Microbiology:

Cefprozil has in vitro activity against a broad range of gram-positive and gram-negative bacteria. The bactericidal action of cefprozil results from inhibition of cell-wall synthesis. Cefprozil has been shown to be active against most strains of the following microorganisms both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.

Cefprozil for oral suspension is indicated for the treatment of patients with mild to moderate infections caused by susceptible strains of the designated microorganisms in the conditions listed below:

Upper Respiratory Tract:

Lower Respiratory Tract:

Skin And Skin Structure:

Cefprozil is contraindicated in patients with known allergy to the cephalosporin class of antibiotics.

BEFORE THERAPY WITH CEFPROZIL IS INSTITUTED, CAREFUL INQUIRY SHOULD BE MADE TO DETERMINE WHETHER THE PATIENT HAS HAD PREVIOUS HYPERSENSITIVITY REACTIONS TO CEFPROZIL, CEPHALOSPORINS, PENICILLINS, OR OTHER DRUGS. IF THIS PRODUCT IS TO BE GIVEN TO PENICILLIN-SENSITIVE PATIENTS, CAUTION SHOULD BE EXERCISED BECAUSE CROSS-SENSITIVITY AMONG ß-LACTAM ANTIBIOTICS HAS BEEN CLEARLY DOCUMENTED AND MAY OCCUR IN UP TO 10% OF PATIENTS WITH A HISTORY OF PENICILLIN ALLERGY. IF AN ALLERGIC REACTION TO CEFPROZIL OCCURS, DISCONTINUE THE DRUG. SERIOUS ACUTE HYPERSENSITIVITY REACTIONS MAY REQUIRE TREATMENT WITH EPINEPHRINE AND OTHER EMERGENCY MEASURES, INCLUDING OXYGEN, INTRAVENOUS FLUIDS, INTRAVENOUS ANTIHISTAMINES, CORTICOSTEROIDS, PRESSOR AMINES, AND AIRWAY MANAGEMENT, AS CLINICALLY INDICATED.

Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including cefprozil, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.

C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin-producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents.

If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated.

General:

Prescribing cefprozil for oral suspension in the absence of proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug resistant bacteria.

In patients with known or suspected renal impairment (see DOSAGE AND ADMINISTRATION), careful clinical observation and appropriate laboratory studies should be done prior to and during therapy. The total daily dose of cefprozil should be reduced in these patients because high and/or prolonged plasma antibiotic concentrations can occur in such individuals from usual doses. Cephalosporins, including cefprozil, should be given with caution to patients receiving concurrent treatment with potent diuretics since these agents are suspected of adversely affecting renal function.

Prolonged use of cefprozil may result in the overgrowth of nonsusceptible organisms. Careful observation of the patient is essential. If superinfection occurs during therapy, appropriate measures should be taken.

Cefprozil should be prescribed with caution in individuals with a history of gastrointestinal disease particularly colitis.

Positive direct Coombs’ tests have been reported during treatment with cephalosporin antibiotics.

Information for Patients:

Phenylketonurics: Cefprozil for oral suspension contains phenylalanine 28 mg per 5 mL                       (1 teaspoonful) constituted suspension for both the 125 mg/5 mL and 250 mg/5 mL dosage forms.

Patients should be counseled that antibacterial drugs including cefprozil for oral suspension should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When cefprozil for oral suspension 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 cefprozil for oral suspension or other antibacterial drugs in the future.

Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibiotic. If this occurs, patients should contact their physician as soon as possible.

Drug Interactions:

Nephrotoxicity has been reported following concomitant administration of aminoglycoside antibiotics and cephalosporin antibiotics. Concomitant administration of probenecid doubled the AUC for cefprozil.

The bioavailability of the capsule formulation of cefprozil was not affected when administered 5 minutes following an antacid.

Drug/Laboratory Test Interactions:

Cephalosporin antibiotics may produce a false positive reaction for glucose in the urine with copper reduction tests (Benedict’s or Fehling’s solution or with Clinitest® tablets), but not with enzyme-based tests for glycosuria (e.g., Clinistix®). A false negative reaction may occur in the ferricyanide test for blood glucose. The presence of cefprozil in the blood does not interfere with the assay of plasma or urine creatinine by the alkaline picrate method.

Carcinogenesis and Mutagenesis and Impairment of Fertility

Long term in vivo studies have not been performed to evaluate the carcinogenic potential of cefprozil.

Cefprozil was not found to be mutagenic in either the Ames Salmonella or E. coli WP2 urvA reversion assays or the Chinese hamster ovary cell HGPRT forward gene mutation assay and it did not induce chromosomal abnormalities in Chinese hamster ovary cells or unscheduled DNA synthesis in rat hepatocytes in vitro. Chromosomal aberrations were not observed in bone marrow cells from rats dosed orally with over 30 times the highest recommended human dose based upon mg/m2.

Impairment of fertility was not observed in male or female rats given oral doses of cefprozil up to 18.5 times the highest recommended human dose based upon mg/m2.

Pregnancy:

Labor and Delivery

Cefprozil has not been studied for use during labor and delivery. Treatment should only be given if clearly needed.

Nursing Mothers

Small amounts of cefprozil (<0.3% of dose) have been detected in human milk following administration of a single 1 gram dose to lactating women. The average levels over 24 hours ranged from 0.25 to 3.3 mcg/mL. Caution should be exercised when Cefprozil for oral suspension is administered to a nursing woman, since the effect of cefprozil on nursing infants is unknown.

Pediatric Use

(See INDICATIONS AND USAGE and DOSAGE AND ADMINISTRATION.)

The safety and effectiveness of cefprozil in the treatment of otitis media have been established in the age groups 6 months to 12 years. Use of cefprozil for the treatment of otitis media is supported by evidence from adequate and well-controlled studies of cefprozil in pediatric patients. (See CLINICAL STUDIES.)

The safety and effectiveness of cefprozil in the treatment of pharyngitis/tonsillitis or uncomplicated skin and skin-structure infections have been established in the age groups 2 to 12 years. Use of cefprozil for the treatment of these infections is supported by evidence from adequate and well-controlled studies of cefprozil in pediatric patients.

The safety and effectiveness of cefprozil in the treatment of acute sinusitis have been established in the age groups 6 months to 12 years. Use of cefprozil in these age groups is supported by evidence from adequate and well-controlled studies of cefprozil in adults.

Safety and effectiveness in pediatric patients below the age of 6 months have not been established for the treatment of otitis media or acute sinusitis, or below the age of 2 years for the treatment of pharyngitis/tonsillitis or uncomplicated skin and skin-structure infections. However, accumulation of other cephalosporin antibiotics in newborn infants (resulting from prolonged drug half-life in this age group) has been reported.

Geriatric Use

Of the more than 4500 adults treated with cefprozil in clinical studies, 14% were 65 years and older, while 5% were 75 years and older. When geriatric patients received the usual recommended adult doses, their clinical efficacy and safety were comparable to clinical efficacy and safety in nongeriatric adult patients. Other reported clinical experience has not identified differences in responses between elderly and younger patients, but greater sensitivity of some older individuals to the effects of cefprozil cannot be excluded (see CLINICAL PHARMACOLOGY).

Cefprozil is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection and it may be useful to monitor renal function. See DOSAGE AND ADMINISTRATIONfor dosing recommendations for patients with impaired renal function.

The adverse reactions to cefprozil are similar to those observed with other orally administered cephalosporins. Cefprozil was usually well tolerated in controlled clinical trials. Approximately 2% of patients discontinued cefprozil therapy due to adverse events.

The most common adverse effects observed in patients treated with cefprozil are:

Gastrointestinal:

Diarrhea (2.9%), nausea (3.5%), vomiting (1%), and abdominal pain (1%).

Hepatobiliary:

Elevations of AST (SGOT) (2%), ALT (SGPT) (2%), alkaline phosphatase (0.2%), and bilirubin values (<0.1%). As with some penicillins and some other cephalosporin antibiotics, cholestatic jaundice has been reported rarely.

Hypersensitivity:

Rash (0.9%), urticaria (0.1%). Such reactions have been reported more frequently in children than in adults. Signs and symptoms usually occur a few days after initiation of therapy and subside within a few days after cessation of therapy.

CNS:

Dizziness (1%). Hyperactivity, headache, nervousness, insomnia, confusion, and somnolence have been reported rarely (<1%). All were reversible.

Hematopoietic:

Decreased leukocyte count (0.2%), eosinophilia (2.3%).

Renal:

Elevated BUN (0.1%), serum creatinine (0.1%).

Other:

Diaper rash and superinfection (1.5%), genital pruritus and vaginitis (1.6%).

The following adverse events, regardless of established causal relationship to cefprozil, have been rarely reported during postmarketing surveillance: anaphylaxis, angioedema, colitis (including pseudomembranous colitis), erythema multiforme, fever, serum-sickness like reactions, Stevens-Johnson syndrome, and thrombocytopenia.

Cephalosporin Class Paragraph:

In addition to the adverse reactions listed above which have been observed in patients treated with cefprozil, the following adverse reactions and altered laboratory tests have been reported for cephalosporin-class antibiotics:

Aplastic anemia, hemolytic anemia, hemorrhage, renal dysfunction, toxic epidermal necrolysis, toxic nephropathy, prolonged prothrombin time, positive Coombs’ test, elevated LDH, pancytopenia, neutropenia, agranulocytosis.

Several cephalosporins have been implicated in triggering seizures, particularly in patients with renal impairment, when the dosage was not reduced. (See DOSAGE AND ADMINISTRATION  and OVERDOSAGE) If seizures associated with drug therapy occur, the drug should be discontinued. Anticonvulsant therapy can be given if clinically indicated.

Renal Impairment:

Cefprozil may be administered to patients with impaired renal function. The following dosage schedule should be used.

Hepatic Impairment:

No dosage adjustment is necessary for patients with impaired hepatic function.

Reconstitution Directions for Oral Suspension:

Prepare the suspension at the time of dispensing; for ease in preparation, add water in two portions and shake well after each aliquot.

Store dry powder at 20°-25°C (68°-77°F) [See USP Controlled Room Temperature].

Store constituted suspension in refrigerator. Discard after 14 days.

Preserve in tight containers.

Study One:

In a controlled clinical study of acute otitis media performed in the United States where significant rates of ßlactamase- producing organisms were found, cefprozil was compared to an oral antimicrobial agent that contained a specific ß-lactamase inhibitor. In this study, using very strict evaluability criteria and microbiologic and clinical response criteria at the 10-16 days post-therapy follow-up, the following presumptive bacterial eradication/clinical cure outcomes (i.e., clinical success) and safety results were obtained:

                                                                      U.S. Acute Otitis Media Study

                                             Cefprozil vs β-lactamase inhibitor-containing control drug

EFFICACY:

SAFETY:

The incidences of adverse events, primarily diarrhea and rash*, were clinically and statistically significantly higher in the control arm versus the cefprozil arm.

Study Two:

In a controlled clinical study of acute otitis media performed in Europe, cefprozil was compared to an oral antimicrobial agent that contained a specific ß-lactamase inhibitor. As expected in a European population, this study population had a lower incidence of ß-lactamase-producing organisms than usually seen in U.S. trials. In this study, using very strict evaluability criteria and microbiologic and clinical response criteria at the 10-16 days post-therapy follow-up, the following presumptive bacterial eradication/clinical cure outcomes (i.e., clinical success) were obtained:

                                                                            European Acute Otitis Media Study

                                                        Cefprozil vs β-lactamase inhibitor-containing control drug

EFFICACY:

SAFETY:

The incidence of adverse events in the cefprozil arm was comparable to the incidence of adverse events in the control arm (agent that contained a specific ß-lactamase inhibitor).