Action And Clinical Pharmacology: Cefadroxil is a cephalosporin with bactericidal activity. In vitro studies have shown that the antibacterial activity of the cephalosporins results from their ability to inhibit mucopeptide synthesis in the bacterial cell wall.
Pharmacokinetics: Cefadroxil is well absorbed following oral administration with 93% of a 500 mg dose being recovered unchanged in the urine after 24 hours. Absorption of cefadroxil from the gastrointestinal tract is not inhibited by the presence of food.
Approximately 20% of the dose of cefadroxil is bound to serum proteins. The apparent volume of distribution is 14 to 17% of body weight.
Lower Respiratory Tissue Levels: Cefadroxil was administered to 7 patients as a 500 mg single dose. At 12 hours, the pleural exudate contained cefadroxil at a level of 2.1 g/mL compared to 0.8 g/mL in the serum.
In another study the mean pleural exudate and mean serum levels following a single 1 g dose of cefadroxil exhibited a similar pattern 3 to 5 hours postadministration (i.e., the pleural fluid concentration is higher than the serum concentration).
Renal Impairment: Single 1 000 mg doses of cefadroxil were administered to 20 fasting patients with varying degrees of renal impairment as determined by creatinine clearance [from anuric to 1.76 mL/s/1.73 m(105.7 mL/min/1.73 m].
Blood and urinary concentrations of cefadroxil were monitored for up to 48 hours postadministration. The results of this study show that as creatinine clearance decreases the elimination rate constant also decreases but the half life increases.
In another study, single 1 000 mg doses of cefadroxil were administered to 8 fasting patients with varying degrees of severe renal impairment. Creatinine clearances varied from 0.004 to 0.54 mL/s/1.73 m (0.24 to 32.35 mL/min/1.73 m. Blood and urinary concentrations were monitored for up to 48 hours postadministration. A linear inverse correlation between the half-life of cefadroxil and creatinine clearance was observed.
Indications And Clinical Uses: The treatment of the following infections when caused by susceptible strains of the organisms indicated:
Acute uncomplicated urinary tract infections caused by E. coli, klebsiella species and some strains of P. mirabilis.
Skin and skin structure infections caused by S. aureus and/or group A beta-hemolytic streptococci.
Acute pharyngitis-tonsillitis when caused by group A beta-hemolytic streptococci.
Lower respiratory tract infections, including pneumonia, caused by S. pneumoniae, S. pyogenes (group A-beta hemolytic streptococci), K. pneumoniae and S. aureus.
Appropriate bacteriological studies should be performed prior to and during therapy in order to identify and determine the susceptibility of the causative organism(s).
Contra-Indications: Patients with a known hypersensitivity to the cephalosporin group of antibiotics.
Manufacturers’ Warnings In Clinical States: In patients with known hypersensitivity to the penicillins, cephalosporin antibiotics, including cefadroxil, should be administered with great caution. There is clinical and laboratory evidence of cross allergenicity between the penicillin and the cephalosporin groups of antibiotics. There are instances of patients who have had reactions to both classes of antibiotics (including fatal anaphylactoid reactions after parenteral administration).
Cefadroxil should be administered with caution and then only when absolutely necessary to any patient who has a history of some form of allergy, particularly to drugs.
If an allergic reaction to cefadroxil occurs, discontinue the drug. Serious acute hypersensitivity reactions may require emergency treatment measures.
Treatment with broad spectrum antibiotics alters normal flora of the colon and may permit overgrowth of clostridia. Studies indicate that a toxin produced by C. difficile is one primary cause of antibiotic-associated colitis.
Pseudomembranous colitis has been reported with the use of cephalosporins and other broad spectrum antibiotics. Therefore, it is important to consider its diagnosis in patients who develop diarrhea in association with antibiotic use.
Mild cases of colitis may respond to drug discontinuance alone. Moderate to severe cases should be managed with fluid, electrolyte and protein supplementation as indicated. When the colitis is not relieved by drug discontinuance or when it is severe, oral vancomycin is the treatment of choice for antibiotic-associated pseudomembranous colitis. Other causes of colitis should also be considered.
Precautions: A minimum of 10 days treatment is recommended for infections caused by group A beta-hemolytic streptococci.
Patients should be carefully monitored to detect the development of any adverse effect or other manifestations of drug idiosyncrasy. If an allergic reaction to cefadroxil occurs, its administration should be discontinued and the patient treated with the usual agents (e.g., epinephrine, other pressor amines or corticosteroids).
Prolonged use of cefadroxil can result in the overgrowth of nonsusceptible organisms. Careful observation of the patient is essential. If superinfection occurs during therapy, the administration of cefadroxil should be discontinued and appropriate measures taken. If an organism becomes resistant during treatment with cefadroxil alternate therapy should be instituted.
Cefadroxil should be used with caution in the presence of markedly impaired renal function (i.e., a creatinine clearance rate of less than 0.85 mL/s/1.73 m(50 mL/min/1.73 m – see Dosage. In patients with known or suspected renal impairment careful clinical evaluation and appropriate laboratory studies should be performed prior to and during therapy, since cefadroxil can accumulate in serum and tissues.
If cefadroxil is to be used for long-term therapy, hematologic, renal and hepatic functions should be monitored periodically.
Positive direct Coombs’ tests have been reported during treatment with the cephalosporin antibiotics. In hematologic studies or in transfusion cross matching procedures, when antiglobulin tests are performed on the minor side or in Coombs testing of newborns whose mothers have received cephalosporin antibiotics before parturition, it should be recognized that a positive Coombs’ test may be due to the drug.
During treatment with cefadroxil, a false positive reaction for glucose in the urine may occur with Benedict’s or Fehling’s solution or with Clinitest tablets, but not with enzyme based tests such as Clinistix or Tes-Tape.
Pregnancy: The safety of cefadroxil in the treatment of infections during pregnancy has not been established. The administration of cefadroxil is not recommended during pregnancy. If, in the opinion of the attending physician, the administration of cefadroxil is considered to be necessary, its use requires that the anticipated benefits be weighed against the possible hazards to the fetus.
Lactation: Cephalosporin antibiotics are excreted in human breast milk, and therefore, would be ingested by the neonate during breast-feeding. Nursing mothers receiving cefadroxil should discontinue breast-feeding.
Adverse Reactions: Adverse effects observed during the use of cefadroxil include: Gastrointestinal: The most frequently observed have been nausea and vomiting. The incidence and severity are dose dependent and the latter has been severe enough to warrant cessation of therapy.
Symptoms of pseudomembranous colitis can appear during or after antibiotic treatment. Other reactions reported were abdominal cramps, gastric upset, heartburn, gas and diarrhea. Rarely dyspesia has been reported.
Hypersensitivity: fever, pruritus, rash, swollen and running eyes, urticaria, eosinophilia, angioedema and positive direct Coombs’ test. These reactions usually subside upon discontinuation of the drug. Erythema multiforme, Stevens-Johnson syndrome, serum sickness and anaphylaxis have been reported rarely.
CNS: dizziness, weakness, drowsiness, vertigo, nervousness and headaches.
Miscellaneous: vaginitis, genital pruritus, genital candidiasis, cramps in side and legs, arthralgia, moderate transient neutropenia and elevations in BUN, alkaline phosphatase and AST.
In common with other cephalosporins, thrombocytopenia and agranulocytosis have been reported rarely.
Symptoms And Treatment Of Overdose: Symptoms and Treatment: Data from a study of children under 6 years of age who had ingested a maximum of 250 mg/kg of penicillin or a cephalosporin derivative suggested that ingestion of less than 250 mg/kg of cephalosporins (i.e., 5 to 10 times recommended dose) is not associated with significant outcomes. No treatment is required other than general support and observation. During the 72-hour evaluation period, most of the children remained asymptomatic. Gastrointestinal disturbances and rash were reported in some children. For amounts greater than 250 mg/kg, induce gastric emptying (emesis induction or gastric lavage).
For information on removal of drug by hemodialysis, see Dosage.
Dosage And Administration: Cefadroxil is administered orally and may be taken without regard to meals.
The incidence and severity of gastrointestinal complaints is dose dependent. Administration with food may be helpful to diminish potential intestinal complaints.
A minimum of 10 days treatment is recommended for infections caused by group A beta-hemolytic streptococci.
Adults: Normal Renal Function: The recommended dose is 1 to 2 g/day.
Urinary Tract Infections: The recommended daily dose is 1 or 2 g. This may be given as a single dose at bedtime or divided into 500 mg to 1 g doses for twice a day administration (every 12 hours). The usual duration of therapy is 10 days. While shorter or longer courses may be appropriate for some patients, cefadroxil should be administered for a sufficient period of time to render the urine sterile. The sterility of the urine should be re-evaluated 2 to 4 weeks after cessation of therapy.
Acute Pharyngitis and Tonsillitis: The recommended dose is 1 g/day in single (daily) or divided doses (b.i.d.). Treatment should be for a minimum of 10 days and continued for a minimum of 48 to 72 hours beyond the time that the patient becomes asymptomatic or evidence of bacterial eradication has been obtained.
Lower Respiratory Tract Infections: The recommended dose is 500 mg to 1 g twice daily (every 12 hours).
Skin and Skin Structure Infections: 1 g daily in a single dose.
Impaired Renal Function: The dosage of cefadroxil should be adjusted according to creatinine clearance rates to prevent drug accumulation.
Patients with creatinine clearance rates greater than 50 mL/min/1.73 mmay be dosed as for those patients with normal renal function.
In 5 adult anuric patients, it was demonstrated that an average of 63% of a 1 g oral dose is extracted from the body during a 6- to 8-hour hemodialysis session.
Children: There is clinical experience for the treatment of urinary tract, and integumentary infections and acute pharyngitis, tonsillitis in children 6 weeks of age and over.
Clinical studies for the treatment of lower respiratory tract infections have been carried out in children 1 year of age and over.
Recommended dose is 30 mg/kg/day in 2 equally divided doses given for 10 days.
Availability And Storage: Each maroon and white hard gelatin capsule contains: cefadroxil USP 500 mg as cefadroxil monohydrate. Nonmedicinal ingredients: magnesium stearate. May contain lactose and silicon dioxide; capsule shell: D&C yellow No. 10 and red No. 33, FD&C blue No. 1 and red No. 3, gelatin, printing ink and titanium dioxide. Bottles of 50 and 100. Store at controlled room temperature (15 to 30°C). (Shown in Product Recognition Section)
DURICEF Bristol Cefadroxil Antibiotic