Concentrations of baclofen in serum and breast milk from a lactating woman.

A lactating woman with spastic paraplegia was given 94 mumol (20 mg) of baclofen orally to study the transport of the drug into breast milk. The concentration of baclofen in serum and milk was determined with a gas chromatographic--mass spectrometric method. The elimination curves in serum and milk showed a similar course, the elimination from milk being delayed about 3 h relative to serum. The total amount of baclofen excreted in the milk during 24 h was about one thousandth of the ingested dose.