General: Prescribing MEIACT in the absence of a 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.
MEIACT is not recommended when prolonged antibiotic treatment is necessary, since other pivalate-containing compounds have caused clinical manifestations of carnitine deficiency when used over a period of months. No clinical effects of carnitine decrease have been associated with short-term treatment. The effects on carnitine concentrations of repeat short-term courses of MEIACT are not known.
In community-acquired pneumonia patients (N=192, mean age 50.3 ± 17.2 years) given a 200 mg BID regimen for 14 days, the mean decrease in serum concentrations of total carnitine while on therapy was 13.8 ± 10.8 nmole/mL, representing a 30% decrease in serum carnitine concentrations. In community-acquired pneumonia patients (N=192, mean age 51.3 ± 17.8 years) given a 400 mg BID regimen for 14 days, the mean decrease in serum concentrations of total carnitine while on therapy was 21.5 ± 13.1 nmole/mL, representing a 46% decrease in serum carnitine concentrations. Plasma concentrations of carnitine returned to the normal control range within 7 days after discontinuation of cefditoren pivoxil. Comparable decreases in carnitine were observed in healthy volunteers (mean age 33.6 ± 7.4 years) following a 200 mg or 400 mg BID regimen. (See Pharmacology under Actions.) Community-acquired pneumonia clinical trials demonstrated no adverse events attributable to decreases in serum carnitine concentrations.
However, some sub-populations (eg, patients with renal impairment, patients with decreased muscle mass) may be at increased risk for reductions in serum carnitine concentrations during cefditoren pivoxil therapy. Furthermore, the appropriate dose in patients with end-stage renal disease has not been determined. (See Patients with Renal Insufficiency under Dosage & Administration).
As with other antibiotics, prolonged treatment may result in the possible emergence and overgrowth of resistant organisms. Careful observation of the patient is essential. If superinfection occurs during therapy, appropriate alternative therapy should be administered.
Cephalosporins may be associated with a fall in prothrombin activity. Those at risk include patients with renal or hepatic impairment, or poor nutritional state, as well as patients receiving a protracted course of antimicrobial therapy, and patients previously stabilized on anticoagulant therapy. Prothrombin time should be monitored in patients at risk and exogenous vitamin K administered as indicated. In clinical trials, there was no difference between cefditoren and comparator cephalosporins in the incidence of increased prothrombin time.
Information for Patients: Patients should be counseled that antibacterial drugs including MEIACT should only be used to treat bacterial infections. They do not treat viral infections (eg, the common cold). When MEIACT 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 MEIACT or other antibacterial drugs in the future.
MEIACT (cefditoren pivoxil) should be taken with meals to enhance absorption.
MEIACT may be taken concomitantly with oral contraceptives.
It is not recommended that MEIACT be taken concomitantly with antacids or other drugs taken to reduce stomach acids. (See Interactions.)
MEIACT tablets contain sodium caseinate, a milk protein. Patients with milk protein hypersensitivity (not lactose intolerance) should not be administered MEIACT.
Carcinogenesis, Mutagenesis, Impairment of Fertility: No long-term animal carcinogenicity studies have been conducted with cefditoren pivoxil. Cefditoren pivoxil was not mutagenic in the Ames bacterial reverse mutation assay, or in the mouse lymphoma mutation assay at the hypoxanthineguanine phosphoribosyltransferase locus. In Chinese hamster lung cells, chromosomal aberrations were produced by cefditoren pivoxil, but not by cefditoren. Subsequent studies showed that the chromosome aberrations were due to the release of formaldehyde from the pivoxil ester moiety in the in vitro assay system. Neither cefditoren nor cefditoren pivoxil produced chromosomal aberrations when tested in an in vitro human peripheral blood lymphocyte assay, or in the in vivo mouse micronucleus assay. Cefditoren pivoxil did not induce unscheduled DNA syntheses when tested. In rats, fertility and reproduction were not affected by cefditoren pivoxil at oral doses up to 1000 mg/kg/day, approximately 24 times a human dose of 200 mg BID based on mg/m2/day.
Use in Pregnancy: Pregnancy-Teratogenic Effects: Pregnancy Category B. Cefditoren pivoxil was not teratogenic up to the highest doses tested in rats and rabbits. In rats, this dose was 1000 mg/kg/day, which is approximately 24 times a human dose of 200 mg BID based on mg/m2/day. In rabbits, the highest dose tested was 90 mg/kg/day, which is approximately four times a human dose of 200 mg BID based on mg/m2/day. This dose produced severe maternal toxicity and resulted in fetal toxicity and abortions.
In a postnatal development study in rats, cefditoren pivoxil produced no adverse effects on postnatal survival, physical and behavioral development, learning abilities, and reproductive capability at sexual maturity when tested at doses of up to 750 mg/kg/day, the highest dose tested. This is approximately 18 times a human dose of 200 mg BID based on mg/m2/day.
There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Labor and Delivery: Cefditoren pivoxil has not been studied for use during labor and delivery.
Use in Lactation: Cefditoren was detected in the breast milk of lactating rats. Because many drugs are excreted in human breast milk, caution should be exercised when cefditoren pivoxil is administered to nursing women.
Use in Children: Use of cefditoren pivoxil is not recommended for pediatric patients less than 12 years of age. The safety and efficacy of cefditoren pivoxil tablets in this population, including any effects of altered carnitine concentration, have not been established. (See General under Precautions.)
Use in Elderly: Of the 2675 patients in clinical studies who received cefditoren pivoxil 200 mg BID, 308 (12%) were >65 years of age. Of the 2159 patients in clinical studies who received cefditoren pivoxil 400 mg BID, 307 (14%) were >65 years of age. No clinically significant differences in effectiveness or safety were observed between older and younger patients. No dose adjustments are necessary in geriatric patients with normal (for their age) renal function. This drug 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 & Administration.)