Excretion of diazepam and its metabolites in human milk during withdrawal from combination high dose diazepam and oxazepam.

The excretion of diazepam, N-desmethyldiazepam, temazepam and oxazepam in breast milk was studied during withdrawal of a 22-year-old patient from combined high dose diazepam and oxazepam therapy. Concentrations of these benzodiazepines in plasma from both the woman and her nursing infant (1 year old) were also documented. Diazepam, N-desmethyldiazepam, temazepam and oxazepam were found in the maternal plasma and milk with mean milk: plasma ratios of 0.2, 0.13, 0.14 and 0.10 respectively. It was calculated on a mg kg-1 basis that the infant received some 4.7% of the maternal dose. Diazepam could not be detected in the infant's plasma, but low levels of N-desmethyldiazepam (20 and 21 micrograms l-1), temazepam (7 micrograms l-1) and oxazepam (7.5 and 9.6 micrograms l-1) were present. The infant showed no overt physical or mental symptoms of benzodiazepine intoxication.