Fetal Risk Summary
Cycloserine is a broad-spectrum antibiotic used primarily for active pulmonary and extrapulmonary tuberculosis. No teratogenic effects were observed in rats given doses up to 100 mg/kg/day through two generations (1).
The Collaborative Perinatal Project monitored 50,282 mother-child pairs, 3 of whom had 1st trimester exposure to cycloserine (2). No evidence of adverse fetal effects was suggested by the data.
The American Thoracic Society recommends avoidance of cycloserine during pregnancy, if possible, due to the lack of information on the fetal effects of the drug (3).
Breast Feeding Summary
Cycloserine is excreted into human breast milk. Milk concentrations in four lactating women taking 250-mg of the drug four times daily ranged from 6 to 19 g/mL, an average of 72% of serum levels (4). Approximately 0.6% of the mother’s daily dose was estimated to be in the milk (5). No adverse effects were observed in the nursing infants (4). The American Academy of Pediatrics considers cycloserine to be compatible with breast feeding (6).
- Product information. Seromycin. Dura Pharmaceuticals, 2000.
- Heinonen OP, Slone D, Shapiro S. Birth Defects and Drugs in Pregnancy. Littleton, MA:Publishing Sciences Group, 1977:297.
- American Thoracic Society. Medical Section of the American Lung Association: Treatment of tuberculosis and tuberculosis infection in adults and children. Am Rev Respir Dis 1986;134:35563.
- Morton RF, McKenna MH, Charles E. Studies on the absorption, diffusion, and excretion of cycloserine. Antibiot Annu 19551956;3:16972. As cited by Snider DE Jr, Powell KE. Should women taking antituberculosis drugs breast-feed? Arch Intern Med 1984;144:58990.
- Vorherr H. Drug excretion in breast milk. Postgrad Med 1974;56:97104. As cited by Snider DE Jr, Powell KE. Should women taking antituberculosis drugs breast-feed? Arch Intern Med 1984;144:58990.
- Committee on Drugs, American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 1994;93:13750.