CEFADROXIL

Fetal Risk Summary

Cefadroxil is an oral, semisynthetic cephalosporin antibiotic. Reproduction studies in mice and rats found no evidence of impaired fertility or fetal harm at doses up to 11 times the human dose (1). Cephalosporins are usually considered safe to use during pregnancy (see other cephalosporins for published human experience).

At term, a 500-mg oral dose produced an average peak cord serum level of 4.6 µg/mL at 2.5 hours (about 40% of maternal serum) (2). Amniotic fluid levels achieved a peak of 4.4 µg/mL at 10 hours. No infant data were given.

In a surveillance study of Michigan Medicaid recipients involving 229,101 completed pregnancies conducted between 1985 and 1992, 722 newborns had been exposed to cefadroxil during the 1st trimester (F. Rosa, personal communication, FDA, 1993). A total of 27 (3.7%) major birth defects were observed (30 expected). Specific data were available for six defect categories, including (observed/expected) 1/1 cardiovascular defects, 0/1 oral clefts, 0/0.5 spina bifida, 2/2 polydactyly, 2/1 limb reduction defects, and 1/2 hypospadias. These data do not support an association between the drug and congenital defects (see also Cefaclor, Cephalexin, and Cephradine for contrasting results).

Cefadroxil, 500 mg twice daily for 10 days following an IV dose of ceftazidime, was used in 12 women for the treatment of asymptomatic bacteruria during the 1st trimester (see also Ceftazidime) (3). No adverse effects of the treatment were observed.

Breast Feeding Summary

Cefadroxil is excreted into breast milk in low concentrations. Following a single 500-mg oral dose, peak milk levels of about 0.6–0.7 µg/mL occurred at 5–6 hours (2). A 1-g oral dose given to six mothers produced peak milk levels averaging 1.83 µg/mL (range 1.2–2.4 µg/mL) at 6–7 hours (4). In this latter group, milk:plasma ratios at 1, 2, and 3 hours were 0.009, 0.011, and 0.019, respectively. Although these levels are low, three potential problems exist for the nursing infant: modification of bowel flora, direct effects on the infant, and interference with the interpretation of culture results if a fever workup is required. The American Academy of Pediatrics considers cefadroxil to be compatible with breast feeding (5).

References

1. Product information. Duricef. Bristol-Myers Squibb Company, 1997.
2. Takase Z, Shirafuji H, Uchida M. Experimental and clinical studies of cefadroxil in the treatment of infections in the field of obstetrics and gynecology. Chemotherapy (Tokyo) 1980;28(Suppl 2):424–31.
3. Nathorst-Boos J, Philipson A, Hedman A, Arvisson A. Renal elimination of ceftazidime during pregnancy. Am J Obstet Gynecol 1995;172:163–6.
4. Kafetzi D, Siafas C, Georgakopoulos P, Papdatos C. Passage of cephalosporins and amoxicillin into the breast milk. Acta Paediatr Scand 1981;70:285–8.
5. Committee on Drugs, American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 1994;93:137–50.