Risk Factor: D
Class: Central nervous system drugs/ Sedatives and hypnotics
Fetal Risk Summary
Oxazepam is an active metabolite of diazepam (see also Diazepam). It is a member of the benzodiazepine group. The drug, both free and conjugated forms, crosses the placenta achieving average cord:maternal serum ratios of 0.6 during the 2nd trimester and 1.1 at term (1). Large variations between patients for placental transfer have been observed (1,2 and 3). Passage of oxazepam is slower than diazepam, but the clinical significance of this is unknown (4). Two reports have suggested that the use of oxazepam in preeclampsia would be safer for the newborn infant than diazepam (5,6). However, it is doubtful whether either drug is indicated for this condition.
A 1989 report described characteristic dysmorphic features, growth retardation, and central nervous system defects in eight infants exposed either to oxazepam, 75 mg/day or more, or diazepam, 30 mg/day or more (7). See Diazepam for a detailed description of the infants. The authors concluded that the clinical characteristics observed in the infants probably represented a teratogenic syndrome related to benzodiazepines (7).
Breast Feeding Summary
Specific data relating to oxazepam usage in lactating women have not been located. Oxazepam, an active metabolite of diazepam, was detected in the urine of an infant exposed to high doses of diazepam during lactation (8). The infant was lethargic and demonstrated an electroencephalographic pattern compatible with sedative medication (see Diazepam).
- Kangas L, Erkkola R, Kanto J, Eronen M. Transfer of free and conjugated oxazepam across the human placenta. Eur J Clin Pharmacol 1980;17:3014.
- Kanto J, Erkkola R, Sellman R. Perinatal metabolism of diazepam. Br Med J 1974;1:6412.
- Mandelli M, Morselli PL, Nordio S, Pardi G, Principi N, Seveni F, Tognoni G. Placental transfer of diazepam and its disposition in the newborn. Clin Pharmacol Ther 1975;17:56472.
- Kanto JH. Use of benzodiazepines during pregnancy, labour and lactation, with particular Reference to pharmacokinetic considerations. Drugs 1982;23:35480.
- Gillberg C. Floppy infant syndrome and maternal diazepam. Lancet 1977;2:6123.
- Drury KAD, Spalding E, Donaldson D, Rutherford D. Floppy-infant syndrome: Is oxazepam the answer? Lancet 1977;2:11267.
- Laegreid L, Olegard R, Walstrom J, Conradi N. Teratogenic effects of benzodiazepine use during pregnancy. J Pediatr 1989;114:12631.
- Patrick MJ, Tilstone WJ, Reavey P. Diazepam and breast-feeding. Br Med J 1972;1:5423.