CEPHALOTHIN

Fetal Risk Summary

Cephalothin is a parenteral, semisynthetic cephalosporin antibiotic. The drug has been used during all stages of gestation (1,2 and 3). Cephalosporins are usually considered safe to use during pregnancy.

No reports linking the use of cephalothin with congenital defects or toxicity in the newborn have been located. The drug crosses the placenta and distributes in fetal tissues (4,5,6,7,8,9 and 10). Following a 1-g dose, average peak cord serum levels were 2.8 µg/mL (16% of maternal peak) at 1–2 hours for the intramuscular route and 12.5 µmg/mL (41% of maternal peak) 10 minutes after IV administration (4,5 and 6). In amniotic fluid, cephalothin was slowly concentrated reaching an average level of 21 µmg/mL at 4–5 hours (5).

Breast Feeding Summary

Cephalothin is excreted into breast milk in low concentrations. A 1-g IV bolus dose given to six mothers produced peak milk levels at 1–2 hours averaging 0.51 µmg/mL (range 0.36–0.62 µmg/mL) (11). Mean milk:plasma ratios at 1, 2, and 3 hours were 0.073, 0.26, and 0.50, respectively. Even though 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. Although not specifically listing cephalothin, the American Academy of Pediatrics classifies other cephalosporin antibiotics as compatible with breast feeding (12).

References

1. Cunningham FG, Morris GB, Mickal A. Acute pyelonephritis of pregnancy: a clinical review. Obstet Gynecol 1973;42:112–7.
2. Harris RE, Gilstrap LC. Prevention of recurrent pyelonephritis during pregnancy. Obstet Gynecol 1974;44:637–41.
3. Moro M, Andrews M. Prophylactic antibiotics in cesarean section. Obstet Gynecol 1974;44:688–92.
4. MacAulay MA, Charles D. Placental transfer of cephalothin. Am J Obstet Gynecol 1968;100:940–5.
5. Sheng KT, Huang NN, Promadhattavedi V. Serum concentrations of cephalothin in infants and children and placental transmission of the antibiotic. Antimicrob Agents Chemother 1964:200–6.
6. Fukada M. Studies on chemotherapy during the perinatal period with special Reference to such derivatives of Cephalosporin C as cefazolin, cephaloridine and cephalothin. Jpn J Antibiot 1973;26:197–212.
7. Paterson L, Henderson A, Lunan CB, McGurk S. Transfer of cephalothin sodium to the fetus. J Obstet Gynaecol Br Commonw 1970;77:565–6.
8. Morrow S, Palmisano P, Cassady G. The placental transfer of cephalothin. J Pediatr 1968;73:262–4.
9. Stewart KS, Shafi M, Andrews J, Williams JD. Distribution of parenteral ampicillin and cephalosporins in late pregnancy. J Obstet Gynaecol Br Commonw 1973;80:902–8.
10. Corson SL, Bolognese RJ. The behavior of cephalothin in amniotic fluid. J Reprod Med 1970;4:105–8.
11. Kafetzis D, Siafas C, Georgakopoulos P, Papadatos CJ. Passage of cephalosporins and amoxicillin into the breast milk. Acta Paediatr Scand 1981;70:285–8.
12. Committee on Drugs, American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 1994;93:137–50.